A minerals research contract repon 

August 1981 

ALS 

.LI 

Contract J0308012 

Terry S. Cory, P.E. 

BUREAU OF MINES * UNITED STATES DEPARTMENT OF THE INTERIOR 

Minerals Heslth and Safety Technology 
The views and conclusions contained in this 

document are those of the authors and should not 

be interpreted as representing the official 

policies or recommendations of the Interior 

Department's Bureau of Mines or of the U. S. 

Government. 
This report describes the results of a measurement and analysis 

program to characterize wireless radio transmission in metal/non-metal 

mines over a wide frequency range from 0.2 - 1000 Mlz and over a 

variety of mine environments. Six mines were chosen based on the 

relative econmic significance of their product to the U.S. economy. 

1 ~r1d.r~. Mum NO. 

I.14aO.I. 

20 Auqust. 1981 L 

L hrtMnkl Orpmm R.W. )*. 

1L Fmhctfl~UIM Unlt M 

m-ml 

Terry S. Cory, P.E. 

2857 Mourt Vernon Rd. S.E. 

Cedar Rapids, Iowa 52403' 

L -rrOnn(uMm.ndldMu 

Office of the AssistantUredor of Mining 

Bureau of Mines 

Deoartment of the Interior. Washington D.C. 20241 

Mine types include oi l shale, uranium, potash, lead/zinc, copper, and 

silver. Particular mines were chosen so that the group would embody 

the most important mining techniques. 

WRT DOCUMEhTATlON '. "Emw *. 

PICE 

11. -0 or ~nnm m. 

(0 50308012 

(a 

1Lh~atWomILP"bd-nd 

Final Report 

8-80 to 8-81 I* 

The results show that transmission at medium frequencies are optimun 

for wireless mine cmmunications, in agreement with extensive testing 

previously performed by the authors in wal mines, and that mine-wide 

wireless systems are feasible with a minimun requirement for new 

dedicated wiring. At least one need for such a wireless system was 

identified in each mine visited. I. DOsu"".a M* r D.-emine ccmnunications,wireless radio transmission, MF-UHF frequencies 

electranagnetic waves, inductive coupling 

2. 

La"lk.4IUr References: Final Revort - Contract H036028 "Propagation of 

IM Signals in Underground Mines1'; and/Final Revort - Contract H0377053 

'E lectrmagnetl c Propagation in Low Coal MI nes at Medl urn Frequencies" 

LlbOrtIUnn;2m~, 

MI. .d .urn. 

Propagation of EM Signals in Underground 

MetaI/Non - Metal Mines 

lulpm) 

Terry S. Cory and Richard J. Mahany 

Mrmlq Orpni..1*n )(.m nd Mdr fOlln ~W~IO~PI~ 

21. NO. at P.W 

264 

L ~r.l~.u~m m- IS. -m UW.~ (mi. rnooltr 

Unclassified 

B him CUa (ml. hbl 

Unclassified We. 

- III.M.LD 1.. 0n-l on kru onlUwL mN 272 (4-7 

(~.-rh nn(us> ~.p."m of Corn-.+=. 
FOREUARD 

This report was prepared by Terry S. Cory, P.E., Cedar Rapids, Iowa 

under USBM Contract number J0308012. The contract was initiated under 

the Coal Mine Health and Safety Program. It was administered under the 

technical direction of PRC with Mr. James R. Means, Jr. acting 

Technical Project Officer. Mr. Alan G. Bolton. Jr. was the contract 

administrator for the Bureau of Mines. This report is a summary of the 

work recently completed as a part of this contract during the period 

August 1980 to August 1981. This report was submitted by the authors 

on August, 1981. 

References to specific brands, equipment, or trade names in 

this report are made to facilitate understanding and do not imply 

endorsement by the Bureau of Mines. 

No patentable concepts of items of technology have resulted from the 

work performed under this contract. 
Table of-antents 

Report Documentation Page ........................... Forward ............................................. Table of Contents ................................... List of Illustrations .............................. List of Tables ...................................... 1 .o Executive Summary-------------------------- 

1.1 Overview of Results------------------------ 

1.2 Application Possibilities------------------ 

1.3 Areas For Further Work-------------------- 

2.0 Introduction .............................. 2.1 Background - Statement of the Problem ---- 

2.2 Metal/Non-Metal Mining Operations Summary - 

2.2.1 Occidental Oil Shale, Inc. Logan Wash Mine2.2.2 United Nuclear/Homestake Partners Section 

23 Mine ----------------------------dm----- 

2.2.3 Kerr-McGee Chemical Corp. Hobbs Potash 

Facility Mine ............................. 2.2.4 Amax Lead Co. of Missouri Buick Mine ----- 

2.2.5 Magma Copper Co. San Manuel Mine --------- 

2.2.6 Hecla Mining Co. Con-Sil Mine ------------- 

2.3 Definition of Communications Requirements - 

2.3.1 Occidental Oil Shale Logan Wash Mine ----- 

2.3.2 United Nuclear/Homestake Partners Section 

23 Mine ................................... 2.3.3 Kerr-McGee Chemical Corp. Hobbs Potash 

Mine Facility ............................. 2.3.4 Amax Lead Co. of Missouri Buick Mine ----- 

2.3.5 Magma Copper Co. San Manuel Mine ---------- 

2.3.6 Hecla Mining Co. Con-Sil Mine ---------- 

2.4 Outline of Performed Work ---------------- 

2.5 Report Contents ........................... 2.6 Definitions of Report Terms, Conventions 

And Nomenclature--------------------------- 

2.6.1 Frequency Ranges--------------------------- 

2.6.2 Loop Antenna Orientations----------------- 

2.6.3 Monofilar Excitation----------------------- 

3.0 Technical Approach ....................... 3.1 Test System Characterization -------------- 

3.1.1 Test System Descriptions ------------------ 

3.1.2 Test and Practical System Characteristics - 

3.2 Categorization of Tests h Test Environments 

3.2.1 Occidental Oil Shale Logan Wash Mine ------ 

3.2.2 United Nuclear/Homestake Partners Section 

23 Mine ................................... 

Page 

1 

2 

3 

5 

19 

24 

24 

2 8 

3 1 

32 

32 

3 3 

3 7 

39 

4 1 

43 

4 5 

4 5 

4 6 

47 

4 7 

47 

48 

49 

5 0 

5 1 

5 2 

53 

53 

53 

54 

5 6 

5 6 

56 

66 

69 

6 9 

77 
Kerr-McGee Chemical Corp. Hobbs Potash 

Facility Mine ............................. 86 

Amax Lead Co. of Missouri Buick Mine ------ 89 

Magma Copper Co. San Manuel Mine ---------- 9 6 

Hecla Mining Co. Con-Sil Mine ------------- 100 

System Performance Considerations --------- 106 

Low-Frequency Coupling Models ------------- 109 

Intermediate Frequency Coupling h 

Attenuation ............................... 115 

Waveguide Transmission .................... 119 

Individual Mine Reduced Test Data --------- 121 

Reduced Data From Occidental Oil Shale 

Logan Wash Mine ........................... 121 

Reduced Data From United Nuclear/Homestake 

Partners Section 23 Mine ----------------- 121 

Reduced Data From Kerr-McGee Hobbs Potash 

Facility Mine ............................. 149 

Reduced Data From Amax Lead Co. Of Missouri 

Buick Mine ............................... 149 

Reduced Data From Magma Copper Co. San 

Manuel Mine ............................... 149 

Reduced Data From Hecla Mining Co. Con-Sil 

, -. 

Presentation of Raw Swept-Frequency .Data - 206 

Raw Data From Occidental Oil Shale Corp. 

Logan Wash Mine ......................... 206 

Raw Data From United Nuclear/Homestake 

Partners Section 23 Mine ----------------- 214 

Raw Data From Kerr-McGee Chemical Corp. 

Hobbs Potash Facility Mine --------------- 222 

Raw Data From Amax Lead Co. Of Missouri 

Buick Mine ................................ 231 

Raw Data From Magma Copper Co. San 

Manuel Mine ............................... 238 

Raw Data From Hecla Mining Co. Con-Sil Mine 254 
Figure 

List of Illustrations 

Page 

1 Mine Wireless Transmission Attenuation 

vs Frequency For Mines Visited @ 1000 

Foot Range - Monofilar Line Attenuation 

and Waveguide Refractive/Roughness Losses - 26 

2 Unattenuated Magnetic Field Strength At 

Drift Center Due to Drift Center 

Excitation of Mine Wiring in Monofilar 

Mode for 1-Watt Transmitter for Flat NIA 

of -2 DB ................................... 27 

Instantaneous Common Mode Noise Levels 

Interpreted as Phone Line Noise Currents 

and Electromagnetic Field Strength at 

2-Meter Spacing From Phone Line ------------ 29 

Medium-Frequency (MF) Swept-Frequency Test 

System Equipment Configuration ------------- 57 

High-Frequency (HF) Swept-Frequency Test 

System Equipment Configuration ------------ 5 8 

Very-High-Frequency (VHF) Swept-Frequency 

Test System Equipment Configuration ------- 5 9 

Ultra-High-Frequency (UHF) Swept-Frequency 

Test System Equipment Configuration ------- 60 

Microwave CW Test System Equipment Configuration .............................. 65 

Multi-Turn Loop Antenna NIA Characteristics 

vs Frequency for 1-Watt of Transmit Power 

Sized for Portable and/or Vehicular 

Operation .................................. 67 

10 Calculated Practical Ihe for VHF for Fixed 

Electric Whip Antenna Length of 0.375 

Meters and for 1-Watt of Transmitter Power - 68 

11 Test and Practical System Geometric 

Current Moments for Induction Field ------- 7 3 

12 Test and Practical System Radiation 

Current Moments for 1-Watt Transmitter ----- 74 
Test System Receive Sensitivity Levels 

Determined on a Computed Basis ------------ 

Occidental Oil Shale Logan Wash Mine 

Swept Frequency Measurement Locations ----- 

Occidental Oil Shale Logan Wash Mine VHF/UHF 

CW Field Strength Measurement Locations ---- 

Occidental Oil Shale Logan Wash Mine Medium 

Frequency CW Field Strength Measurement 

Locations .................................. Occidental Oil Shale Logan Wash Mine Loop 

Excited Monofilar Mode 650KHZ Field Strength 

Measurement Locations ---------------ad-e--- 

Occidental Oil Shale Logan Wash Mine Current 

Probe Excited Monofilar Mode 650KHZ Field 

Strength Measurement Locations ------------ 

United Nuclear/Homestake Partners Section 

23 Mine Map Showing Main Swept Measurement 

TX and RX Test Locations and MF Coupled 

Phone Line Receive Locations (MF Coupled 

Probe at TX Location in Wagner Drift) ------ 

United Nuclear/Homestake Partners Section 

23 Mine Hap Showing MF Coupled Phone Line RX 

Locations (MF Coupled Probe at TX Location 

in Wagner Drift) ........................... United Nuclear/Homestake Partners Section 

23 Mine Map of Wagner Area Showing Principal 

Swept Frequency TX & RX Locations. Plus RX 

Locations for CW VHF Tests & MF Coupled 

Power Line Tests ........................... United Nuclear/Homestake Partners Section 

23 Mine Map of Wagner Area Showing RX 

Locations for CW VHF Tests & MF Coupled 

Power Line Tests ........................... United Nuclear/Homestake Partners Section 

23 Mine Wagner Drift Cross-section Between 

Primary Swept Frequency TX and RX Locations. 

Floor Assumed to be Flat ------------------ 
Kerr-McGee Hobbs Potash Facility Area 

140Mine Map Showing Swept Frequency Field 

Strength Measurement Locations (100KHZ - 

1000MHZ) .................................. Kerr-McGee Hobbs Potash Facility Area 

140 Mine Map Showing Medium Frequency 

Continuous Wave Field Strength Measurement 

Location (250KHZ. 650KHZ and 950KHZ) ------- 

Kerr-McGee Hobbs Potash Facility Area 

140 Room 225 Mine Map Showing UHF Continuous 

Wave Field Strength Measurement Locations 

(600MHZ and 900MHZ) ........................ Kerr-McGee Hobbs Potash Facility Mine Map 

Showing Locations of Conductor-Enhanced 

650KHZ Field Strength Measurement Locations 

and lOGHZ Microwave Field Strength 

Measurement Locations ..................... Map of North Mine Leg of Amax Buick Mine 

Showing Transmit and Receive Locations Used 

During Measurements With Transmit Locations 

for CW & Swept Range Tests Shown ---------- 

Map of North Mine Leg of Amax Buick Mine 

Showing Transmit and Receive Locations Used 

During Measurements With Transmit Location 

for Swept-Frequency Tests Shown------------ 

Mine Map of 2375 Haulage Level of the Magma 

Copper Mine Showing Locations Employed on 

the Measurement Traverses for Evaluating the 

USA 1680*Carrier Phone Performance ------- 

Drift Cross-sectional Geometries Encountered 

During Swept-Frequency Measurements in the 

Magma Copper Co. San Manuel Mine Car-Cleaner 

Drift ...................................... Track Coupling Geometry for Swept-Frequency 

Measurements in Mag'ma Copper Co. San Manuel 

Mine ----------------------

* Reference to Saeclflc brands, equipment, or trade names In thls 

report Is made to racllltate understanding and does not Imply 

endorsement by the Bureau of Mlnes. 
Drift Cross-sectional Geometry Viewed in the 

Inby Direction Shbwing HMD Test Antenna 

Locations -,Hecla Con-Sil Mine ------------- 102 

Drift Cross-sectional Geometry Viewed in the 

Inby Direction Showing VMD Test Antenna 

Locations - Hecla Con-Sil Mine ------------ 

Mine Map of Hecla Mining Co. Con-Sil Mine 

Showing Swept-Frequency Test Locations ----- 

Mine Map of Hecla Mining Co. Con-Sil Mine 

Showing CW and Talk Test Locations --------- 

Summary of Wireless Transmission Magnetic 

Field Strength Characteristics Obtained in 

Mines #I, #2 and 13; 1 Watt Transmit PowerSummary Wireless Transmission Magnetic Field 

Strength Characteristics Obtained in Mines 

#4, #5 and 16; 1 Watt Transmit Power ------ 

Geometries of Cases for 1/R Magnetic Field 

Fall-Off ................................... 

Monofilar Track Coupling Model Geometry --- 

MF/HF Characterization of Track as a 

Monofilar Conductor Comparing Computed 

Currents Derived from Magnetic Field 

Strength Data - Magma Copper Co. San Manuel 

Mine - 1 Watt Transmit Power -------------- 

Geometry for Intermediate Frequency Coupling 

Swept-Frequency MF/HF Measurements in North 

Mine With Tx at Y and With Rx at 064 Ore 

Pass 390 Feet Away - Amax Lead Co.Buick Mine 

Illustration of Monofilar Coupling Effects 

Including Attenuation. Phase Cancellation 

and Impedance .............................. Occidental Oil Shale Logan Wash Mine Retort 

#6 Area - Medium Frequency Swept Field 

Strength Measurements at Two Fixed Ranges 

1 Watt Power into Practical Man-Pack Loop 

Antenna Characterization - Conductor-Free -- 
Occidental Oil Shale Logan Wash Mine Retort 

#6 Area - High Frequency Swept Field 

Strength Measurements at 120 Feet Ranges 

1 Watt Power into Practical Man-Pack Loop 

Antenna Characterization Conductor-Free --- 

Occidental Oil Shale Logan Wash Mine Retort 

$6 Area - VHF Swept Frequency Field Strength 

Measurements at Two Fixed Ranges - 1 Watt 

Power into Practical Man-Pack Whip Antenna 

Characterization Conductor-Free ------------ 

Occidental Oil Shale Logan Wash Mine Retort 

16 Area - UHF Swept Field Strength 

Measurements at 240 Feet Range - 1 Watt 

Power into Practical Man-Pack Whip Antenna 

Characterization Conductor-Free ------------ 

Occidental Oil Shale Logan Wash Mine Retort 

16 Area - VHF/UHF Vertical Wave Guide Mode 

(Horizontal Antennas) - 1 Watt Power into 

Practical Man-Pack Whip Antenna Characterization - CW Tests ......................... Loop-Excited MF Monofilar Mode Propagation 

Field Strength Measurements for 1 Watt 

Transmit Power into a Practical Man-Carried 

Loop Antenna Located Twenty Feet from the 

Local Conductors (650 KHz Signal) - Logan Wash Mine ................................ Current Probe Coupled MF Monofilar Mode 

Propagation Measurement Using a Pager Phone 

Cable and 1.2 Watts Transmit Power at 650 

KHz - Logan Wash Mine .................... Microwave Frequency Field Strength 

Measurements (10 GHZ) - Logan Wash Mine ---- 

Comparison of Computed and Measured Medium 

Frequency Swept-Frequency Data Taken in the 

Wagner Area of Section 23 Mine for Both 

Current Probe and Wireless Excited Modes of 

Transmission via Coupling into 480 VAC Line 

for 1 Watt Transmit Power and 180 Foot Range 
54 Comparison of Computed and Measured Medium 

Frequency Swept-Frequency Data Taken in the 

650 Track Area of Section 23 Mine for Both 

Current Probe and Wireless Excited Modes of 

Transmission via Coupling into a Conductor 

Ensemble. Probe Attached to the Phone Line 

for 1 Watt Transmit Power at 180 Foot Range - 134 

55 High-Frequency Swept-Frequency Data Taken 

in Wagner Area of Section 23 Mine for Both 

Current Probe and Wireless Excited Modes of 

Transmission via Coupling into 480 VAC Line 

for 1 Watt Transmit Power at 180 Foot Range -- 136 

56 VHF Swept-Frequency Data Taken in Wagner Area 

of United Nuclear Section 23 Mine for Several 

Polarization Orientations of Biconical Test 

Antennas - Normalized for 1-Watt into 

Practical Man-Pack Whip Antenna Characterization at 180 Foot Range ....................... 138 

57 VHF Swept-Frequency Data Taken in 650 Track 

Area of United Nuclear Section 23 Mine for 

Several Polarization Orientations of Biconical 

Test Antennas - Normalized for 1-Watt into 

Practical Man-Pack Whip Antenna Characterization at 180 Foot Range ...................... 139 

58 UHF Swept-Frequency Data Taken in Wagner Area 

of Section 23 Mine for Both Principal Polarizations of the Log-Periodic Test Antennas 

Normalized for 1 Watt into Practical Man-Pack 

Whip Antenna Characterization at 180 Foot 

Range ........................................ 142 

5 9 UHF Swept-Frequency Data Taken in 650 Track 

Area of Section 23 Mine for both Principal 

Polarizations of the Log-Periodic Test 

Antenna - Normalized for 1 Watt into Practical 

Man-Pack Whip Antenna Characterization at 180 

Foot Range .................................. 143 

6 0 Processed MF and HF Data From Wagner Area of 

United Nuclear Section 23 Mine at 180 Foot 

Test Range for Flat NIA of -2dB ------------- 150 
Kerr-McGee Hobbs Potash Facility Mine Area 

140 - BTX3 Medium Frequency Swept Field 

Strength Measurements at Two Fixed Ranges - 

1 Watt Power into Practical Man-Pack Loop 

Antenna Characterization with Conductors 

Present ...................................... 152 

Kerr-McGee Hobbs Potash Facility Mine Area 

140-BTX3 High Frequency Swept Field Strength 

Measurements at 300 Feet Range 1 Watt Power 

into Practical Man-Pack Loop Antenna Characterization with Conductors Present ---------- 153 

6 3 Kerr McGee Hobbs Potash Facility Mine Area 

140-BTC3 VHF Swept Field Strength Measurements at two Fixed Ranges - 1 Watt Transmit 

Power into Practical Man-Pack Whip Antenna 

Characterization with Conductors Present ----- 154 

6 4 Kerr-McGee Hobbs Potash Facility Mine Area 

140-BTX3 UHF Swept Field Strength Measurements into a Practical Man-Pack Whip Antenna 

150 Feet Range ............................... 155 

65 Current Probe Medium Frequency Field Strength 

Measurements at 300 Feet Range Kerr-McGee 

Hobbs Potash Facility Mine Area 140-BTC3 

Including Both Empirical and Theoretical Data- 156 

66 Kerr-Mcgee Hobbs Potash Facility Mine Area 

140-BTX3 Medium Frequency Continuous Wave 

Field Strength Measurements vs. Range 1 Watt 

Power into Practical Man-Pack Loop Antennas 

With Conductor Enhancement 250KHz. 650 KHz 

and 950 KHz .................................. 157 

67 Kerr-McGee Hobbs Potash Facility Mine 650 KHz 

Conductor Enhanced Field Strength Measurement 

Data 1 Watt Transmit Power into Practical 

Vehicular Antenna Characterization ----------- 159 

68 Kerr-McGee Hobbs Potash Facility Mine Room 

225/Area 140 UHF Continuous Wave Field 

Strength Measurements (600MHz and 950 MHz) 

For 1 Watt Transmit Power into Practical Whip 

Antennas ..................................... 161 
Processed MF and HF Data From Kerr-McGee 

Potash Mine on 150-Foot Test Range for Flat 

NIA of -2dB With and Without Attenuation ----- 163 

Magnetic Field Strength vs Range along North 

Mine Tracked Haulageway for 1 - Watt 

Transmitter Loop-Coupled Into Dedicated Wire 

at50-450 KHz - Amax Lead Co. Buick Mine ----- 164 

Magnetic Field Strength vs Range Along North 

Mine Tracked Haulageway for 1 - Watt 

Transmitter Loop-Coupled into Dedicated 

Wire at550-950 KHz Amax Lead Co. Buick Mine - 165 

Magnetic Field Strength VS Range Along North 

Mine Tracked Haulageway for 15 - Watt 

Transmitter Loop-Coupled into Dedicated 

Wire or Phone Line Using Collins Prototype 

Base Station in Foreman's Shack - 520 KHz 

Amax Lead Co. Buick Mine .................... 168 

Swept-Frequency MF/HF Measurements in North 

Mine with TX at Y and with RX at 064 Ore 

Pass 390 Feet Away RX Antenna 1 Meter Below 

Conductors Amax Lead Co. Buick Mine -------- 170 

Swept-Frequency MF/HF Measurements in North 

Mine with TX at Y and with FIX at 049 Ore 

Pass 1290 Feet Away - 1 Watt Transmit Power 

RX Antenna 1 Meter Below Conductors - Amax 

Lead Co. Buick Mine ......................... 173 

Swept-Frequency VHF/UHF Measurements in North 

Mine with TX at Y and with RX at 064 Ore Pass 

390 Feet Away - 1 Watt Transmit Power into 

Practical Whip Antennas -Amax Lead Co. Buick 

Mine ....................................... 176 

Processed MF and HF Data from Amax Lead Co. 

Buick Mine on 390-Foot Test Range for Flat 

NIA of -2 DB With and Without Attenuation --- 179 

MF/HF Characterization of Track as a 

Monofilar Conductor Comparing Computed 

Currents and Currents Derived From Magnetic 

Field Strength Data - Magma Copper Co. 

Sari Manuel Mine ............................. 180 
78 Computed MF/HF Monofilar Mode Track 

Coupling Corresponding to Car-Cleaner 

Drift Measurements - Magma Copper Co. San 

Manuel Mine ................................. Swept-Frequency VHF Reduced Data For 

Practical Whip Antennas Taken in Car-Cleaner 

Tracked Drift at a Range of 111 Feet from 

the Transmitter - 1 Watt Transmit Power 

Magma Copper Co. San Manuel Mine ------------ 

80 Swept-Frequency UHF Reduced Data Taken in 

Car-Cleaner Tracked Drift at a Range of 

243 Feet from the Transmitter For Practical 

Whip Antennas - Magma Copper Co. San Manuel 

Mine - 1 Watt Transmit Power ---------------- 

Test System Reduced MF Data Expressed as 

Monofilar Mode Current from Carrier Phone 

Testing on Base-Vehicles and Vehicle-Base 

Paths at 145KHz abd 520KHz Respectively - 

Magma Copper Co. San Manuel Mine - 1 Watt 

Transmit Power 

82 Reduced Data Expressed as Monofilar Mode 

Current Levels on Vehicle-Base Path at 520 

KHz Differentiating Between Current Received 

in Radio Shop and that Expected on the 

Trolley Conductor System - Magma Copper Co. 

Sari Manuel Mine ............................ 

8 3 Processed MF and HF Data from Magma San 

Manuel Mine on 243-Foot Test Range for 

Flat NIA of -2 DB for HMD and VMD Antenna 

Orientations - 1 Watt Transmit Power and Test 

System Antennas ............................ 84 Reduced Magnetic Field Strength Data at 

MF/HF Taken on 429 Foot Path in 3000- 

Level North Crosscut Hecla Con-Sil Mine ---- 

85 Reduced Data Expressed as Monofilar Line 

Current Normalized to NIA-Unity Taken on 

429 Foot Path in 3000-Level North 

Crosscut Hecla Con-Sil Mine ---------------- 
Reduced Electric Field Strength Data for 

VHF/UHF Horizontal Polarization Taken in 

3000-Level North Crosscut on a 195 Foot 

Path (Location 2) - 1 Watt Transmit - 

Practical Whip Antennas - Hecla Con-Sil 

Mine ...................................... 198 

Reduced Electric Field Strength Data for 

VHF/UHF Vertical Polarization Taken in 

3000-Level North Crosscut on a 195 Foot 

Path (Location 2) - 1 Watt Transmit Power 

Practical Whip Antennas - Hecla Con-Sil 

Mine ........................................ 199 

Reduced CW MF Magnetic Field Strength 

Data Taken in Direction of Sunshine 

Raise From Both Test Set and Collins 

1-Watt Radios - Hecla Con-Sil Mine ---------- 202 

Reduced Magnetic Field Strength Data 

Taken on 3000-Level Toward Con-Sil 

Winze Using Collins 520KHz FM Radio and 

650KHz Test Set - 1 Watt Transmitters - 

Hecla Con-Sil Mine .......................... 203 

Processed MF and HF Data from Hecla ConSil Mine on 429-Foot Test Range for Flat 

NIA of -2 DB With and Without 

Attenuation - Data Obtained Using Test System Equipment ................................... 205 

Medium Frequency Swept Field Strength 

Original Oscillographs - Logan Wash Mine ---- 207 

High Frequency Swept Field Strength 

Original Oscillographs - Logan Wash Mine ---- 208 

VHF Swept Frequency Field Strength 

Original Oscillographs - Logan Wash Mine --- 209 

VHF Swept Frequency Field Strength 

Original Oscillographs - Logan Wash Mine ---- 210 

VHF Swept Frequency Field Strength 

Original Oscillographs - Logan Wash Mine ---- 211 

UHF Swept Frequency Field Strength 

Original Oscillographs - Logan Wash Mine ---- 212 
UHF Swept Frequency Field Strength 

Original Oscillographs - Logan Wash Mine ---- 213 

Original Oscillographs of MF Swept 

Frequency Data Taken in Wagner Area 

of United Nuclear Section 23 Mine ----------- 215 

Original Oscillographs of MF Swept 

Frequency Data Taken in 650 Track 

Area of United Nuclear Section 23 Mine ------ 216 

Original Oscillographs of HF Swept 

Frequency Data Taken in Wagner Area 

of Section 23 Mine ......................... 217 

Original Oscillographs of VHF Swept 

Frequency Data Taken in Wagner Area 

of United Nuclear Section 23 Mine ----------- 218 

Original Oscillographs of VHF Swept 

Frequency Data Taken in 650 Track 

Area of United Nuclear Section 23 Mine ------ 219 

Original Oscillographs of UHF Swept 

Frequency Data Taken in Wagner Area 

of United Nuclear Section 23 Mine ----------- 220 

Original Oscillographs of UHF Swept 

Frequency Data Taken in 650 Track Area 

of United Nuclear Section 23 Mine ----------- 221 

Medium Frequency Swept Field Strength 

Original Oscillographs - Kerr McGee Hobbs 

Potash Facility - 150 Feet Range ------------ 223 

Medium Frequency Swept Field Strength 

Original Oscillographs - Kerr McGee Hobbs 

Potash Facility - 300 Feet Range ----------- 224 

High Frequency Swept Field Strength 

Original Oscillographs - Kerr McGee Hobbs 

Potash Facility - 150 Feet Range ------------ 225 

High Frequency Swept Field Strength 

Original Oscillographs - Kerr McGee Hobbs 

Potash Facility - 300 Feet Range ------------ 226 

VHF Swept Frequency Field Strength 

Original Oscillographs - Kerr McGee Hobbs 

Potash Facility - 150 Feet Range ------------ 227 
VHF Swept Frequency Field Strength 

Original Oscillographs - Kerr McGee Hobbs 

Potash Facility - 300 Feet Range ----------- 228 

UHF Swept Frequency Field Strength 

Original Oscillographs - Kerr McCee Hobbs 

Potash Facility - 150 Feet Range ------------ 229 

Medium Frequency Swept Field Strength 

Original Oscillographs - Kerr McGee Hobbs 

Potash Facility - 300 Feet Range - Current 

Probe Excitation ............................ 230 

Original Oscillographs of MF Swept 

Frequency Data at 064 Ore Pass: Tx @ 

North Mine Y - Amax Lead Co. Buick Mine ----- 232 

Original Oscillographs of HF Swept 

Frequency Data at 064 Ore Pass; Tx @ 

North Mine Y - Amax Lead Co. Buick Mine ----- 233 

Original Oscillographs of MF Swept 

Frequency Data at 049 Ore Pass; Tx at 

North Mine Y - Amax Lead Co. Buick Mine ----- 234 

Original Oscillographs of HF Swept 

Frequency Data at 049 Ore Pass; Tx at 

North Mine Y - Amax Lead Co. Buick Mine ----- 235 

Original Oscillographs of VHF Swept 

Frequency Data Taken in the North 

Mine Tracked Haulageway at the 064 

Ore Pass; Tx Located at Y - Amax Lead Co. 

Buick Mine .................................. 236 

Original Oscillographs of UHF Swept 

Frequency Data Taken in the North Mine 

Tracked Haulageway at the 064 Ore Pass; 

Tx Located at Y - Amax Lead Co. Buick Mine -- 237 

Original Oscillographs of MF Swept Frequency 

Data Taken on Car-Cleaner Track Drift 

Magma Copper Co. San Manuel Mine ------------ 239 

Original Oscillographs of HF Swept Frequency 

Data Taken on Car-Cleaner Track Drift 

Magma Copper Co. San Manuel Mine ------------- 240 
Original Oscillographs of VHF Swept Frequency 

Data Taken in the Car-Cleaner Tracked Drift 

Magma Copper Co. San Manuel Mine ------------- 241 

Original Oscillographs of UHF Swept Frequency 

Data Taken in the Car-Cleaner Tracked Drift 

Magma Copper Co. San Manuel Mine ------------- 242 

Original Oscillographs from 520 KHz Carrier 

Phone Testing, Vehicle-Base Locations A-C 

Magma Copper Co. San Manuel Mine ------------- 243 

Original Oscillographs from 520 KHz Carrier 

Phone Testing. Vehicle-Base Locations D-G 

Magma Copper Co. San Manuel Mine ------------- 244 

Original Oscillographs from 520 KHz Carrier 

Phone Testing, Vehicle-Base Locations G-J 

Magma Copper Co. San Manuel Mine ------------- 245 

Original Oscillographs from 520 KHz Carrier 

Phone Testing, Vehicle-Base Locations K-M 

Magma Copper Co. San Manuel Mine ------------- 246 

Original Oscillographs from 520 KHz Carrier 

Phone Testing. Vehicle-Base Locations N-Q 

Magma Copper Co. San Manuel Mine ------------- 247 

Original Oscillographs from 520 KHz Carrier 

Phone Testing, Vehicle-Base Locations R-S 

Magma Copper Co. San Manuel Mine ------------- 248 

Original Oscillographs from 520 Khz Carrier 

Phone Testing, Vehicle-Base Locations T-V 

Magma Copper Co. San Manuel Mine ------------- 249 

Original Oscillographs from 520 KHz Carrier 

Phone Testing, Vehicle-Base Locations W-X 

Magma Copper Co. San Manuel Mine ------------- 250 

Original Oscillographs from 145 KHz Carrier 

Phone Testing, Base-Vehicle Locations G-K 

Magma Copper Co. San Manuel Mine ------------- 25 1 

Original Oscillographs from 145 KHz Carrier 

Phone Testing, Base-Vehicle Locations M-Q 

Magma Copper Co. San Manuel Mine ------------ 252 
Original Oscillographs from 145 KHz Carrier 

Phone Testing, Base-Vehicle Locations 9-X 

Magma Copper Co. San Manuel Mine ------------- 253 

Original Oscillographs of MF Swept Frequency 

Data Taken Along 3000-Level North Crosscut HMD 

& Probe Configurations - Hecla Con-Sil Mine -- 255 

Original Oscillographs of MF Swept Frequency 

Data Taken Along 3000-Level North Crosscut 

VMD Configurations - Hecla Con-Sil Mine ----- 256 

Original Oscillographs of HF Swept Frequency 

Data Along 3000-Level North Crosscut - HMD 

and Probe Configurations w/o Frequency Index 

Reference - Hecla Con-Sil Mine --------------- 257 

Original Oscillographs of HF Swept Frequency 

Data Along 3000-Level North Crosscut - VMD 

Configurations w/o Frequency Index 

Reference - Hecla Con-Sil Mine --------------- 258 

Original Oscillographs of HF Swept Frequency 

Data Along 3000-Level North Crosscut - Probe 

and VMD Configurations with Frequency Index 

Reference - Hecla Con-Sil Mine --------------- 259 

Original Oscillographs of VHF Swept Frequency 

Data Along 3000-Level North Crosscut with 

Antennas at Drift Center at Location 1 - 

Hecla Con-Sil Mine ........................... 260 

Original Oscillographs of VHF Swept Frequency 

Data Along 3000-Level North Crosscut with 

Antennas at Drift,Center at Location 2 

Hecla Con-Sil Mine ........................... 261 

Original Oscillographs of UHF Swept Frequency 

Data Along 3000-Level North Crosscut with 

Antennas at Drift Center at Location 1 

Hecla Con-Sil Mine ........................... 262 

Original Oscillographs of UHF Swept Frequency 

Data Along 3000-Level North Crosscut with 

Antennas at Drift Center at Location 2 

Hecla Con-Sil Mine ........................... 263 
--------- List of Tables 

Table Page 

1 Estimated UHF Unattenuated Field Strengths 

for Selected Individual Mines for 1-watt 

Transmitter Power--------------------------- 28 

MF & HF Magnetic Field Strength Correction 

Factors--------------------------------- 70 

VHF & UHF Electric Field Strength Correction 

Factors------------------------------------ 71 

Magnetic Field Strength Data Correction 

Factors for Use with Stoddard Current Probe- 72 

Distances to Locations Along the Measurement 

Traverse on the 2375 Haulage Level---------- 101 

Distances to CW Locations on 3000-Level of 

Con-Sil Mine-------------------------------- 107 

VHF/UHF CW Field Strength Measurement Data 

- Logan Wash Mine--------------------------- 127 

Loop Excited Monofilar Mode 650 KHz Field 

Strength Measurement Data - Logan Wash 

Mine--------------------------------------- 129 

Microwave Field Strength Measurement' Data - 

Logan Wash Mine----------------------------- 132 

Reduced Swept-Frequency MF Data Taken in 

Wagner Area United Nuclear Section 23 Mine 

1 Watt Transmit Power at 180 Foot Range ---- 135 

Reduced Swept-Frequency MF Data Taken in 

650 Track Area United Nuclear Section 23 

Mine - 1 Watt Transmit Power at 180 Foot 

Range ...................................... 135 

Reduced Swept-Frequency HF Data Taken in 

Wagner Area United Nuclear Section 23 Mine 

1 Watt Transmit Power at 180 Foot Range ---- 137 

Reduced Swept-Frequency VHF Data Taken in 

Wagner Area United Nuclear Section 23 Mine 

1 Watt Transmit Power at 180 Foot Range ---- 140 
Reduced Swept-Frequency VHF Data Taken in 

650 Track Area of United Nuclear Section 23 

Mine - 1 Watt Transmit Power at 180 Foot 

Range ...................................... 

Reduced Swept-Frequency UHF Data Taken in 

Wagner Area United Nuclear Section 23 Mine 

1 Watt Transmit Power at 180 Foot Range --- 

Reduced Swept-Frequency UHF Data Taken in 

650 Track Area United Nuclear Section 23 

Mine - 1 Watt Transmit Power at 180 Foot 

CW Medium Frequency Data in Wagner Drift 

Area at 650 KHz United Nuclear Section 23 

Mine ....................................... CW Medium Frequency Data Over Large 

Area from TX Located in Principal 

Wagner Area Location of United Nuclear 

Section 23 Mine with Coupling to Phone Line 

via, Stoddard Current Probe at 650 KHz ----- 

CW VHF Data Taken in Wagner Drift Area 

United Nuclear Section 23 Mine ------------- 

X- Band Microwave Test Data Taken in 

Wagner Area United Nuclear Section 23 Mine 

1 Watt Transmit Power ...................... 

Summary of Conductor Ensemble Impedances 

Deduced from Measurements United Nuclear 

Section 23 Mine ........................... Medium Frequency Continuous Wave Field 

Strength Measurement Data Kerr-McGee 

Hobbs Potash Facility Mine Area 140-BT C3 

1 Watt Transmit Power ...................... Conductor-Enhanced Medium Frequency 

Continuous Wave Field Strength 

Measurements - Kerr McGee Hobbs Potash 

Facility - 650 KHz Test Frequency - 1 Watt 

Transmit Power ............................ 
UHF Continuous Wave Field Strength 

Measurement Data Kerr-McGee Hobbs Potash 

Facility Mine Room 225 (Horizontal 

Antenna Polarization)-1 Watt Transmit Power- 162 

Microwave Frequency Continuous Wave 

Field Strength Measurement Data KerrMcCee Hobbs Potash Facility Room 27 West 

( 1 Watt Transmit Power - 10 GHz) ---------- 162 

Reduced Magnetic Field Strength Data 

Taken on a Swept-Frequency Basis with 

Range Along the North Mine Tracked 

Haulage Drift Away From a. 1-Watt 

Transmitter Loop-Coupled into the 

Dedicated Wire in the Foreman's Shack 

Amax Lead Co. Buick Mine-------------------- 166 

Results of MF CW Demonstration Testing 

at 520 KHz using Collins Prototype Base 

Station as the Transmitter in the 

Foreman's Shack and using a Singer Field 

Strength Meter plus a Portable Collins 

Unit Along the North Mine Tracked 

Haulage Drift - Amax Lead Co. Buick Mine --- 169 

Reduced Magnetic Field Strength and 

Coupled Current Data Taken on a SweptFrequency Basis at 064 Ore Pass from a 1 

Watt Transmitter Located at the Northwest/ 

Northeast Y - Amax Lead Co. Buick Mine ----- 171 

Reduced Magnetic Field Strength and 

Coupled Current Data taken on a Swept 

-Frequency Basis at 064 Ore Pass from a 

1 Watt Transmitter Located at the Northwest/ 

Northeast Y - Amax Lead Co. Buick Mine ----- 172 

Reduced Magnetic Field Strength and 

Coupled Current Data taken on a SweptFrequency Basis at 049 Ore Pass from a 

1 Watt Transmitter Located at the Northwest/ 

Northeast Y - Amax Lead Co. Buick Mine ---- 174 

Reduced Magnetic Field Strength and 

Coupled Current HF Data Taken on a SweptFrequency Basis at 049 Ore Pass from a 

1 Watt Transmitter Located at the Northwest/ 

Northeast Y - Amax Lead Co. Buick Mine. ---- 175 
32 Reduced VHF Electric Field Strength Data 

taken on a Swept-Frequency Basis along 

the North Mine Tracked Haulage Drift at 

064 Ore Pass from a Transmitter Located 

at the Northwest/Northeast Y - 1 Watt 

Transmit Power for Practical Whip Antennas 

Amax Lead Co. Buick Mine ------------------- 177 

33 Reduced UHF Electric Field Strength Data 

taken on a Swept-Frequency Basis along the 

North Mine Tracked Haulage Drift at 064 Ore 

Pass from a Transmitter Located at the 

Northwest/Northeast Y - 1 Watt Transmit 

Power for Practical Whip Antennas - Amax 

Lead Co. Buick Mine 178 

34 Reduced Magnetic Field Strength and 

Coupled Current Data taken on a SweptFrequency Basis in the Car-Cleaner Track 

Drift Which Contained no other Significant 

Conductors at MF - 1 Watt Transmit Power 

Magma Copper Co. San Manuel Mine ---------- 181 

35 Reduced Magnetic Field Strength and Coupled 

Current Data taken on a Swept-Frequency 

Basis in the Car-Cleaner Track Drift 

Which Contained no other Significant 

Conductors at HF - 1 Watt Transmit Power 

Magma Copper Co. San Manuel Mine ----------- 182 

36 Reduced Data From 145 KHz Carrier phone 

Tests on the Base-Vehicle Linkage Along 

the Measurement Traverse - Magma Copper Co. 

San Manuel Mine - 1 Watt Transmit Power --- 188 

37 Reduced Data from 520 KHz Carrier phone 

Tests on the Vehicle-Base Linkage along 

the Measurement Traverse - Magma Copper Co. 

Sari Manuel Mine 190 

38 Reduced Magnetic Field Strength and 

Coupled Current Data taken on a SweptFrequency Basis in the 3000 Level North 

Crosscut on a 429 Foot Path at MF for VMD 

Antenna Orientations - 1 Watt Transmit Power 

for Test System Antennas - Hecla Con-Sil 

Mine ....................................... 793 
3 9 Reduced Magnetic Field Strength and 

Coupled Current Data taken on a SweptFrequency Basis in the 3000-Level North 

Crosscut on a 429 Foot Path at HF for 

HMD Antenna Orientations-1 Watt Transmit 

Power- Hecla Con-Sil Mine ------------------ 194 

40 Reduced Magnetic Field Strength and 

Coupled Current Data taken on a SweptFrequency Basis in the 3000-Level North 

Crosscut on a 429 Foot Path at HF for 

VMD Antenna Orientations - 1 Watt Transmit 

Power - Hecla Con-Sil Mine ----------------- 195 

4 1 Reduced Magnetic Field Strength and 

Coupled Current Data Taken on a SweptFrequency Basis in the 3000 Level North 

Crosscut on a 429 Foot Path a HF for 

HMD Antenna Orientations - 1 Watt Transmit 

Power - Hecla Con-Sil Mine ----------------- 196 

42 Reduced VHF Electric Field Strength Data 

Taken on a Swept-Frequency Basis on a 

195 Foot Path in the 3000-Level North 

Crosscut - 1 Watt Transmit Power - Practical 

Whip Antennas - Hecla Con-Sil Mine --------- 200 

43 Reduced UHF Electric Field Strength Data 

Taken on a Swept-Frequency Basis on a 

195 Foot Path in the 3000-Level North 

Crosscut - 1'Watt Transmit Power - Practical 

Whip Antennas - Hecla Con-Sil Mine -------- 201 

44 Reduced MF CW Magnetic Field Strength Data 

Taken on a Swept-Frequency Basis on a 195 

Foot Path in the 3000-Level North Crosscut 

of Hecla Con-Sil Mine using 1 Watt Test 

System Equipment 204 
1.0 EXECUTIVE SUMMARY 

Wireless radio communication possibilities were assessed in six 

metal/non-metal mines representing a var led cross section of 

mine types having major economic significance. The assessment 

comprised both the electrical measurement and analysis of transmission 

characteristics and characterization of the operational utility 

achievable through the use of wireless communications. The measurement 

of characteristics was conducted over the frequency range of 0.2-1000 

MHz using modern swept-frequency techniques. 

Prior to this program, the feasibility and utility of wireless 

communications at medium frequencies (MF) in coal mines and at 

ultra-high frequencies (UHF) in large rock mines was established. 

Additionally, UHF leaky feeder systems requiring a special cable were 

implemented commercially in a variety of mine types. The results of 

this program show that MF transmission is feasible and optimum in all 

metal/non-metal mine drifts having existing wiring regardless of the 

area of the drift cross section. This result is contrary to that 

observed for UHF signals. where communications are restricted to mines 

with large drift cross sections, due to excessive refractive and 

roughness (scattering) losses encurred in small drifts. 

As in coal mines, the use of MF frequencies provides the most viable 

basis for the implementation of mine-wide "wirelessn communications. In 

most metal/non-metal mines, MF communications can be effectively used 

to streamline haulage operations and locate key underground supervisory 

and maintenance personnel. MF systems can also provide advance 

warning of impending health and safety problems in mine working areas 

where permanent mine wiring 'and fixed communications are not 

economically feasible. 

Also. as in coal mines, the transmission of MF carrier current in 

existing mine wiring is observed to be minimally effected by details of 

the wireplant routing and terminations. 

These findings are timely in view of joint ongoing USBM and industry 

sponsored development activities to produce mine-worthy MF wireless 

communications equipment. 

1.1 OVERVIEW OF RESULTS 

Based on characteristics of attenuation versus range, useful wireless 

transmission is limited to frequencies in the MF and HF bands from 

approximately 200KHz to lMHz and in the UHF band above 200MHz to 

400MHz. VHF frequencies were unusable in all of the visited mines. 

The MF/HF attenuation was measured over all MF and HF frequencies in 
two of the mines and over limited regions at MF in three others. 

Generally, the attenuation in drifts varied directly with frequency, 

with 6 dB11000 feet at 1 MHz being representative of the observed 

attenuation in the visited mines. To achieve reasonable parity in UHF 

transmission in the mines, an operating frequency of at least 800 - 

1000 MHz must be used. At a range of 1000 feet at these frequencies, 

the UHF signal levels are within 20 db of their unattenuated values. 

Figure 1 shows the composite attenuation data for all visited mines. 

The UHF data has been computed using the ADL model for refractive and 

roughness losses and the individual mine drift cross-sectional 

geometries. The low-frequency attenuation data is a composite of 

measured and computed values. 

The use of MF frequencies has proven to be optimum for close-proximity 

inductive coupling. Previous data from coal mines has verified MF to be 

optimum for both direct through-the-seam and remote proximity coupling 

to mine wiring. Prior to this program, the coupling loss was thought to 

decrease monotonically with frequency through at least most of the HF 

region for close-proximity coupling. The results of this program have 

disproven this hypothesis and have confirmed that optimum coupling is 

restricted to the HF range. The models developed to account for these 

effects are equally applicable to coal and metalfnon-metal mines. The 

precise "round trip" coupling was determined to be a function of 

coupling geometry in the drift cross section ( where "round trip" is 

defined as the field strength incident on a receiving antenna in a 

drift due to an inductively coupled transmit antenna source). 

The unattenuated "round trip" coupling for a 1-watt transmitter with 

NIA of -2 dB (below unity) for transmit and receive antennas located 

at the drift centers is shown in Figure 2. This figure illustrates 

several of the variables related to coupling geometry. A curve of 

receive system sensitivity is also included so that estimates of 

system dynamic range and "allowable attenuation" can be made when 

combined with an estimate of the external noise environment of a 

particular mine. The low-frequency coupling (providing the 

monotonic coupling increase with frequency) varied over a range of 

about 20 dB due to: the separation of antennas from the conductors; 

the proximity of the conductors to nearby conducting surfaces; and, to 

variations in the conductor ensemble driving point impedance. The 

intermediate frequency performance is effected by the separation of 

the antennas from the conductors and the phase velocity and standing 

wave conditions on the monofilar or bifilar line(s) formed by the 

excited conductors. Generally, the coupling roll-off in the 

intermediate (largely HF) frequency region is due to phase shifts along 

the line(s) over the coupling region of the antenna. If the coupling 

region is large (as in a large drift crossection with attendent larger 

separation between antennas and conductors) the roll-off is extremely 

rapid with the coupling approaching a limit 20-30 dB below the optimal 
I 10 

FREQUENCY - HZ 
0. I I 

FREQUENCY - MHz 
MF coupling level. If the coupling range is short and/or the line 

phase velocity approaches free space values (due to back or ribs 

covered with metal mesh) the roll-off is more gradual. The data 

presented in the figure is normalized for an assumed flat NIA which is 

increasingly difficult to achieve above the MF band, for the fixed 

antenna size and transmit power limitations of practical systems. A 

practical NIA characterization (based on the forementioned 

limitations) given in Section 3.0 shows an approximate l/f NIA 

fall-off above about 2 MHz, which further optimizes the MF region for 

coupling. 

A chart of observed mine noise values is given in Figure 3. which may 

be used in conjunction with the preceding figures to enable estimates 

of signal margin for systems deployed in these mines. Additionally, 

estimates of the unattenuated UHF signal levels at about 1000 MHz are 

given below in Table 1. 

TABLE 1 

ESTIUATED UHF UNATTENDED FIELD STRENGTHS FOR 

SELECTED INDIVIDUAL MINES FOR ?-WATT TRANSMITTER POWER 

USING LOG PERIODIC ANTENNA 

ELECTRIC FIELD STRENGTH MAGNETIC FIELD STRENGTH 

MINE # dB ABOVE 1 MICRO-VOLT/M dB ABOVE 1 MICRO-AMP/M 

+lo4 

+I22 H-POL 

+I52 V-POL 

+I16 

+I01 

+122 

Detailed test data from each mine including continuous wave field 

strength measurements with range at or near optimum frquencies is 

given in Section 4.0. Some continuous wave microwave test data at 10 

GHz was also gathered during this program. This data. also included in 

Section 4.0. has little apparant significance and is not elaborated 

upon in this report. 

1.2 APPLICATION POSSIBILITIES 

The simplist application is the implementation of one-way voice or 

tone paging from a central dispatch location using existing mine 

wiring, with key supervisory and/or maintenance personnel carrying 

pocket pagers. Alternative "page" or "alertn applications might include 

an alarm system with alarm receivers at critical fixed locations within 

audible range of working areas. Such systems are faster and more 

accurate than existing power interruption or stench warning systems. 
10 100 

FREQUENCY (KHz) 
The most useful application is providing two-way voice communications 

from a fixed dispatch location to mobile haulage vehicles and/or 

maintenance/supervisory vehicles or personnel. Such a system may 

substantially improve the haulage efficiency of largely horizontally 

distributed mines with multiple muck handling operations. (This 

application was common to most of the mines visited.) For example, 

communication can be established between product and mining levels, in 

most of the visited mines without requiring any additional wiring. 

MF transmission is advantageous since it couples onto, follows and is 

radiated from existing mine wiring. It can be viewed in its simplest 

form as a higher frequency extention of carrier phone capability. The 

carrier phone equipment cannot directly operate on an inductively 

coupled basis because the lower frequency carrier phone signals suffer 

substantial coupling losses unless the antennas and conductors are 

very close. Further, most carrier phone transceivers have insufficient 

sensitivity to operate effectively in wireless applications. In 

certain instances, dedicated wire added to and simply interfaced with 

existing mine wiring can extend the signal propagation into remote 

mine areas or between mine power grids and ensure total mine-wide 

communications. Such wiring can consist of any common mine wire (such 

as pager phone or AC power wire and does not need to be a special 

cable. In the few mines experiencing high attenuation (the haualge 

level at AMAX being an example) the dedicated wiring can be configured 

as an MF leaky feeder. 

A base station can be inductively or directly coupled to existing mine 

wiring at a single location. Short lengths of dedicated wire can be 

used to reduce transmit coupling losses when direct feeding is not 

feasible. The inductive coupling of a fixed-located transmitter 

results in a 25-30 dB reduction in coupled current. This is not 

detrimental in many cases, because the mines are small enough and 

attenuation is low enough that mine-wide communication is still 

directly possible. For large or greatly attenuated mines, reducing 

this loss through special treatment of the fixed-located radio may be 

advantageous and may mimimize the requirements for a repeater. 

However, repeaters are expected to be required for mine-wide coverage 

of some mines. 

The greatest advantage of wireless MF communication is the ability to 

communicate between any locations in the mine (near existing wiring) 

without being restricted to fixed locations such as .phones. 

Communication with vehicles or personnel in motion is also possible 

and has potential desireability for some mines. In one mine (Con-Sil), 

communication with a cage in motion in a shaft was demonstrated. 
1.3 AREAS FOR FURTHER WORK 

The data base accrued during this program supports the applicability of 

MF wireless equipment for the communication needs of metal/non-metal 

mining operations. The results from this program augment the preceding 

6-7 years of testing in coal mines to establish an overwhelming level 

of confidence in the capabilities and usefulness of medium-frequency 

wireless communications in all underground mines. 

Areas for future work should focus on the results obtained from 

configuring and installing the first of several practical system 

embodiments with regard to the technical details of selecting optimum 

frequencies, repeater requirements and special line treatments. These 

activities will provide "levels of refinementN only and are not 

directly related to specific aspects of operational feasibility. 

More importantly, the economic benefits of improving productivity and 

the health and safety in mining operations due to improved wireless 

communications needs to be evaluated to provide a cost-basis incentive 

for mines to make use of the new communication equipment which is 

becoming available. 

Finally. the Bureau should act immediately to standardize wireless mine 

equipment operational specifications (similar to the standards for 

pager phones) to encourage the compatibility of system components from 

the multiple communication equipment supply sources that will appear 

as the mine MF communication market develops. 
2.0 INTRODUCTION 

This report presents the results of wide-frequency wireless radio 

propagation measurements performed under U.S. Bureau of Mines Contract 

50308012, "Propagation of EM Signals in Underground Metal/Non-Metal 

Minesw. This work, performed over a nominal 9-month period from 

September 1980 through May 1981, has entailed the characterization of 

wireless radio transmission in six metal/non-metal mines. This 

characterization was performed over a continuous frequency range from 

0.2 - 1000 MHz supplemented with limited testing at a spot frequency 

of 10 GHz. 

2.1 BACKGROUND - STATEMENT OF THE PROBLEM 

The research reported herein is an extension of previously performed 

wireless radio characterization studies in coal mines by Terry S. 

Cory, P.E. under two previous Contracts H0366028, "Propagation of EM 

Signals in Underground Mines", and H0377053, "Electromagnetic 

Propagation in Low Coal Mines at Medium Frequencies". These previous 

studies were limited in frequency range to 0.1 - 4 MHz using continuous 

wave (CW) instrumentation. The current work has employed modern 

swept-frequency techniques in addition to CW testing, thus enabling 

more efficient and comprehensive characterization of mines. 

The previous work. beginning in 1974-1975, was performed in 

conjunction with a U.S.B.M. sponsored prototype radio development by 

Rockwell/Collins under Contract H0346067 and a companion analytical 

study by Arthur D. Little under U.S.B.M. Contract H0346045. The 

previous work established the feasibility of local coal seam 

transmission at medium frequencies at ranges to 1600 feet in 

conductor-free areas and long range transmission via inductive 

coupling into existing mine wiring up to four miles. 

Within the last two years, the mine supply industry has become 

interested in extending carrier phone communication capabilities to 

vehicles and personnel on a wireless basis, and in providing 

equivalent carrier phone communications in mines without DC haulage. 

The current work is very timely as it roughly coincides with the first 

introduction of mature wireless communications hardware to the 

marketplace by the Mine Safety Appliance Company. This introduction 

has been greatly aided and expedited by the U.S.B.M. development 

sponsorship of a modern set of medium frequency wireless radio system 

elements by A.R.F. Products Co. under Contract H0308004. 

The potential of improving the health, safety and operational 

efficiency in coal mining operations through wireless communications 

with roving vehicles and personnel has long been recognized by the 
Bureau. But the efficacy of wireless communications in metal/non-metal 

mines in terms of either technical feasibility or operational 

significance has not been shown to the mine electronics community. 

This is because t h e w i d e v a r i a t i o n s in mining techniques, topologies 

and geological parameters which exist in these metal/non-metal mines 

have precluded the tacit extension of the previous work. Thus, a goal 

of this current work has been to attain an understanding of the varied 

operations in these mines and to seek out common needs and 

possibilities for improved communications. 

A compendium o f w i r e l e s s communication system design information has 

previously been prepared by the authors under U.S.B.M. Contracts 

50395072 and H0377013. "Wireless Communications for Trackless Haulage 

Vehiclesn. This work compiled the results of the foregoing referenced 

wireless work with all other pertinent work known by the authors at 

that time, circa 1979. This compendium provides the data base for the 

current program. Although an updating of this rather comprehensive 

compendium is beyond the scope of this contract, the current results 

compliment the compended data and extend its general applicability. 

To date, neither large scale developmental or operational wireless 

systems exist in mines, except for a few instances where carrier phone 

operation has been extended t o m o v i n g vehicles through the use of 

inductive vehicular antennas. Generally. the relatively poor 

sensitivity of carrier phone systems has precluded their proliferation 

in this application. UHF systems employing reflectors and repeaters 

have also been adapted to mines on a limited basis however their 

utility is largely limited to line of sight applications (such as 

along haulageways) and complete mine-wide coverage is untenably 

expensive for most mines (as evidenced by the limited number of 

operational systems in spite of the technological feasibility and 

product availability which now spans a decade). 

Wireless medium frequency technology is now at the threshold of 

operational realization and a proliferation of wireless implementations 

is expected to occur in the mining industry over the next few years. 

The authors hope that this work will provide a significant contribution 

to this growth in wireless mine communications. 

This report has been written as a practical document which may be used 

on an industry-wide basis by qualified system applications people in 

addition to scientific researchers. It is not a "stand-alonen document, 

however, and the design of complete systems is additionally referenced 

to reports from the foregoing contracts. 

2.2 METAL/NON-METAL MINING OPERATIONS SUMMARY 

Mines were selected (from information found in the 1980 ELMJ 
INTERNATIONAL DIRECTORY OF MINING AND MINERAL PROCESSING OPERATIONS 

and from 1980 MSHA comvuter ~rintouts vrovided bv the MSEA ~~~ ~ ~~ 

Health ---- ~- and ---- 

Safety Analysis ~entir in Denver, colorado) according to general 

criteria including the following: 

- significance of the product being mined 

- size of the mine 6 number of employees 

- type of ore, metal or non-metal 

- type of ore deposit 

- type of mining technique 

Mines considered as viable candidates for this program were comprised 

of non-metallnon-rock mines (of which there are 105 total) with 100 

employees or more (of which there are 26); and metal mines (more than 

800) with 100 employees or more (of which there are 73). Statistics on 

the non-metallnon-rock mines include: 

- total mines 105 

- fewer than 25 employees 6 3 

- w125-50 employees 6 

- wI50-100 employees 10 

- ~1100-200 employees 9 

- ~1200-400 employees 13 

- greater than 400 employees 5 

- 60% have fewer than 25 employees 

- 15% have 25-100 employees 

- 25% have greater than 100 employees 

Similar statistics for metal mines were not assessed for fewer than 100 

employees due to the large number of mines involved. However, for both 

non-metallnon-rock and metal mines, most are very small and there are 

only about 100 mines total in both categories with 100 employees or 

more. 

By ore type for metal mines, the top four in decending order of 

importance by number of employees are: 

- copper 

- uranium 

- leadlzinc 

- molybdenum, 
and by the number of mines are: 

- lead/zinc 

- uranium 

- copper 

- silver. 

There are only three molybdenum mines in the U.S. and there probably 

will not be more in the near future, so these mines were ruled out as 

being of primary importance for the purposes of this study. Copper, 

uranium and lead/zinc were left as the top three based on the number 

of employees. the number of mines and their continuing strategic and 

economic importance. 

Precious metal mines are not necessarily rankable in importance by 

mine size or number of employees because of the economic value of 

their product. A silver mine in the Cour d1Alene mining district, 

was added to the top three metals in lieu of other types of precious 

metal mines (measurements are also required there by the contract). 

Additionally, metal mines are probably of more economic importance 

than are non-metal mines. Four out of the six mines available for 

selection were chosen to be metal mines. 

By ore/product type for non-metal/non-rock mines, the top four in 

decending order both by number of mines and number of employees are: 

- salt 

- potash (potassium oxide) 

- sodium 

- oil shale. 

A potash mine was selected for testing because: 

- the mining operations and topologies are more like coal 

mines than for any other ore type 

- the overburden and underburden are salt: thus, 

constituitively, a potash mine is a salt mine except 

for topological details. Further, due to the extent of 

the salt layers, the strata presents a nearly homongenous 

(nearly theoretically ideal) medium for testing 

propagation. 

An oil shale mine was selected for testing in lieu of sodium because 

of the anticipated economic importance and the expected rapid 
proliferation of these mines in the near future. 

The top five states in terms of number of mines of both metal and 

non-metallnon-rock ores are: 

- New Mexico 

- Missouri 

- Colorado 

- Tennessee 

- Idaho. 

Five of the six selected mines were located in the above list and the 

sixth mine in Arizona. 

The mine types selected for testing during this program, in order of 

visitation, were as follows: 

- Oil Shale (Western Colorado) 

thick bedded deposit; multi-level 

in-situ retort 

- Uranium (Northwestern New Mexico) 

bedded deposit in sandstone; 

irregular room 6 pillar in stopes 

varying with grade of ore 

- Potash (Southern New Mexico) 

bedded deposit in massive salt 

deposit 

- LeadIZinc (Eastern Missouri) 

bedded deposit 

- Copper (Southern Arizona) 

massive deposit; block caving 

used 

- Silver (Northern Idaho) 

deep-vein metal 
The following subsections summarize the operations and other salient 

characteristics of the visited mines. 

2.2.1 OCCIDENTAL OIL SHALE, INC. LOGAN WASH MINE 

Occidental Oil Shale, Inc., in cooperation with the Department of 

Energy. has developed an "in-situ" process for the extraction of crude 

oil from oil shale in their experimental Logan Wash mlne outside of 

Grand Junction. Colorado. Oil shale is fragmented and heated in massive 

crucibles (called retorts) to vaporize the entrapped oil, which is 

then condensed, collected' and refined. The new process consists of 

the fabrication of retorts underground from the strata surrounding the 

ore to be processed. The retorts are ignited and result in a 

gasification of the oil with subsequent condensation and flow of oil 

from the retort base. The operation at Logans Wash involves 

development of three levels which are located at the top. middle and 

base of the retorts. with approximately 100 feet of separation between 

levels. Future operations may permit elimination of the middle level. 

The retorts are configured in rows along drifts that are twenty to 

thirty feet wide and ten to twenty feet in height. The drifts are 

connected by perpendicular crosscuts at regular intervals so that the 

mine topology has the appearance of a dense matrix of retorts, which 

share common oil pumping and off-gas lines. The technology developed 

at Logan Wash will be applied in a production facility at Occidental 

Oil Shale's Cathedral Bluff facility, which is being designed at this 

time and is expected to become operatonal in the mid 1980's. 

Oil shale is stratified, massively disseminated rock, which is normally 

bounded by other grades of shale. Typical strata may extend from 

several feet to several thousand feet in depth. Due to the vast 

deposits of oil shale in Colorado, Utah, and Wyoming (and the obvious 

economic factors). the largest and most homogeneous deposits will be 

initially mined. The mine development consists of sinking vertical 

shafts and driving drifts with conventional mining equipment. 

Trackless haulage vehicles are used to remove the excess shale, which 

is transported to conventional surface retorting operations. The 

proposed development at Cathedral Bluff will use a combination of 

belt and trackless haulage conveyance systems. The drifts are 

supported by roof bolts and wire mesh. The mining operation results in 

the release of methane gas, so that that monitoring and ventilation 

systems similar to those used in coal mines are required, when 

"high-density" ore is being mined. The consistent use of explosives 

and the gassy environment necessitate the use of intrinsically safe 

communication equipment for both vehicular and man-carried equipment. 

A retort is fabricated by sinking a shaft and placing rings of 

explosives along the shaft height to systematically rubblize the 

interior rock. The intact rock around the retort then acts as the 
retort casing. The retort is sealed, pressure tested, and the top 

surface of the fragmented rock is ignited. Steam and air are injected 

to heat the retort to 900-1000 degrees F. The heat and pressure cause 

gasification of .the oil near the flame front, which then diffuses 

downward, condenses, and flows out of a pipe at the retort base. 

Initially, an oil/water slurry drains from the base which is collected 

and separated. In addition to the fluid mixture, a substantial amount 

of exhaust gas ("off-gasw) is generated by the retort, which contains 

the characteristic products of raw hydro-carbon combustion (CO, CO . H S and some uncombusted hydrocarbons). The off-gas is piped to a 

surface processing plant which scrubs and neutralizes the gas before 

venting it to the atmosphere. The flame front is sustained by gasified 

oil and blown-in air and slowly progresses downward in the retort. The 

retort actively produces oil for approximately nine months and then 

slowly burns out over a period of another year. 

The oil production consists of two discrete phases which have separate 

communication requirements. The mining and fabrication of the retorts 

is the first phase and had operational communication requirements 

similar to multi-level, multi-working section coal mining operations. 

Communication links are required to hoists, within working sections 

(between all three levels), along haulageways and conveyor belts, and 

to the surface support plants: mine support (ventilation, dewatering. 

haulage); surface processing (surface shale transport operations); and 

utilities (electricity, water, fuel). The mining phase requires 

ventilation monitoring for LEL methane (the lowest explosive level at 

which methane/air mixtures will ignite) and air flow. 

The second operational phase is the process control phase which is 

conducted by a separate group of technical personnel. The process 

control group coordinates the plumbing, sealing. firing and monitoring 

operations associated with the oil extraction process. Process control 

activities include tracking the fire front in the retorts (and 

redirecting it if necessary), evaluating the off-gas composition (as 

an indication of retort performance), evaluating the air purification 

process and monitoring the gas and fluid lines for leakage. 

Communication links are required locally at the retorts (between the 

levels and along the drifts) and to the surface plants. including the 

off-gas processing plant. Monitoring is required at regular intervals 

along the off-gas lines and to track the flame front in the retorts. 

The fully operational system at Cathedral Bluff will contain 

ninety-six producing retorts. with equivalent numbers in fabrication 

and "cooling-downw. Substantial separation between mining and 

producing areas will be maintained to preserve the integrity of the 

active retort structures from the stress of blasting and the drift and 

shaft mining operations. 
The Logan Wash mine has been used to develop the production techniques 

and procedures for fabricating and operating the in-situ retorting 

system. The facility operates on three active levls underground and on 

the surface of a mesa which is approximately 2.500 feet above the local 

terrain. The propagation tests were conducted on the lowest or 

"productn level at the end of the L-700 drift near Retort C6. The rock 

along the drift was observed to be a stratified deposit of common and 

oil shale of varying composition. 

2.2.2 UNITED NUCLEAR/HOMESTAKE PARTNERS SECTION 23 MINE 

The United Nuclear/Homestake Partners uranium mines are located in the 

Ambrosia Lake district of Northwestern New Mexico. This district, 

together with contiguous areas in this part of New Mexico. contains 

approximately 50% of the known uranium deposits in the world. Mining 

in this overall region has been in progress for between 20 and 30 

years. 

Two distinctive types of ore bodies are encountered in the district, 

and are referred t o a s primary (trend) and secondary (redistributed) 

deposits. These deposits are located approximately 500-800 feet 

beneath the relatively flat Ambrosia Lake surface. 

The primary ore bodies vary from a few inches thick at the edges to 

typically seven feet at the nrolln near the center, and seldom exceed 

17 feet. The primary ore is a dark grey-to-black medium grained 

sandstone. The typical ore body lateral extent is approximately 200 

feet, but they occasionally reach as much as 1000 feet in length. The 

secondary ore bodies are larger and range in thickness between seven 

and 150 feet . The object of uranium mining is to take the ore with as little waste 

as possible. Once a particular body is located and mining begins, an 

effort is made to minimize the size of stope cross sections for the 

thin ores. The principal mining technique is the stope and raise 

method. Because of the discrete and physically variable nature of the 

ore bodies. a number of variations of the mining technique are often 

employed within a single mine. Normally within a local area two 

levels are employed, however, the depth of these levels will vary 

within the overall mine topology and the composite mine will likely 

embody a number of slightly offset levels. The stope areas are 

relatively small and are somewhat random, depending on what must be 

done to get the ore. In the rare cases where the ore bodies are thicker 

than the usual stope height of seven feet,, a "minin block caving 

("scramn) method is used by constructing several short raises within 

the stopes and pulling the ore until the upper ore body limit is 

reached. For larger ore bodies of relatively uniform lateral extent. 

the stope areas employ a limited room-and-pillar geometry with pillars 
on about 30 foot centers. 

The most common means of mining the smaller ore bodies employs 

slushers to "pull" the dynamited ore to a single muck pocket raise. 

The slusher is a small drag line with a winch on the head or drum end 

(operable from 480 VAC) with a pulley on the tail end. The pillars are 

eventually pulled with temporary timber support being provided. 

In developing an ore body. drifts are driven (30-50feet) beneath the 

deposit. Access and muck pocket raises are then extended vertically 

into the body. with subsequent horizontal stope development. Ore body 

probing. surveying and detailing are performed every shift to provide 

effective production control of the mining. 

Historically, the haulage was 100% tracked using diesel motors and a 

string of 8-ton (%yard) cars. This permitted the use of the narrowest 

haulage drifts (typically seven feet high and 10-feet wide). 

Currently, the haulage is a mixture of tracked and rubber tired (using 

diesel articulated dump trucks); although, the final haulage to the 

main portal shaft muck and waste pockets for skipping is tracked. The 

rubber tired haulage developed as a consequence of the second major 

variation in mining technique, called "Wagnertw mining. The name of 

this type is based on use of a brand name (Wagnert) small loader that 

is used in lieu of slushers for loading the ore for transport to the 

muck pocket raise grizzleys. Wagnert mining offers great flexibility 

in developing haulage topologies in the mine, but requires larger 

drifts for the trucks and larger stopes for the loaders. Hence, more 

potential waste per ton of ore mined. 

To illustrate the varied topology and haulage procedures involved, a 

small ore body may use a slusher to develop the stopes and fill the 

stope muck pocket. These pockets may be pulled either by a truck or a 

train. If the muck is pulled by a truck motorman, the muck is then 

hauled and dumped into another muck pocket for loading onto a train; 

which, in turn, hauls the muck (and/or waste) to the primary muck 

pocket at the main portal shaft for skipping to the surface. 

l Reference to specific brands, equipment, or trade names in this 

report is made to facilitate understanding and does not imply 

endorsement by the Bureau of Mines. 
The uranium oxide, U308, constituency of primary ore runs 10% or 

better. Dilution of the ore in the mined material occurs because the 

ore cross section per drift/stope is frequently smaller than the total 

cross section size required for the mine vehicles and equipment. The 

concentration per volume of material mined in the primary trend is 

roughly 0.3-0.45, which at $30 per pound (1981 value provided by mine 

personnel) has a net value of $180-$240 per ton. The secondary ore is 

,approximately 0.4% uranium oxide, but does not suffer as severe a 

dilution in volume of material mined because the larger ore deposits 

are more congruent with the standard drift/stope cross sections. The 

concentration per volume of material mined in a secondary ore body may 

average 0.15-0.2%. yielding $90-$120 per ton at current (1981) values 

of $30 per pound of *yellow caken. 

Contract rate determination is an important aspect of uranium mining 

management in this area. Typical tonnage output of section mines runs 

500 to 1000 tons per day. The actual mining in the stopes is performed 

by two-man crews working on a contract basis. A very active mine will 

employ up to 20 crews per shift. The crews are reimbursed on a 

percentage basis of production which exceeds a predetermined "break 

evenn level, in addition to a base wage. The IE process in these mines 

includes in-situ sampling of the ore. Samples are taken each shift to 

determine specifically how the stope development in each mined area 

should proceed during the following shift. The shifter on each level 

has the considerable responsibility of overseeing the planning 

details of mining each day on each level. The close and continuous 

inspection of the mine development by the mine management and the use 

of industrial engineering provides visibility to mine management which 

compensates in some respects for the limitations of the dilutely 

implemented communication system currently used in the mine. 

2.2.3 KERR-MCGEE CHEMICAL CORP. HOBBS POTASH FACILITY MINE 

The Kerr-McGee Hobbs Potash Facility is one of seven separately 

operated potash mines located along a thirty mile section of Route 82 

between Carlsbad and Hobbs, New Mexico. These mines employ 

approximately three thousand persons and produce 97% of the potash 

mined in the United States with a daily production of 56.000 tons of 

ore. (Canada is the world's leading producer with a production of 

99,000 tons per day.) Six of the mines (including the Kerr-McGee mine) 

operate on one level, while one mine, the Amax Chemical Corporation 

mine, operates on four levels. The potash ore is typically a bedded 

sedimentary deposit nominally ranging in depth from two to eight feet 

and bordered by "saltn (sodium chloride) deposits which are hundreds 

of feet in depth. "High-graden ore is a transparent crystalline solid 

characterized by a blue isotope which is randomly diffused through the 

ore body. Typical ore has a 15 to 30% yield and is observed to be 

rust-colored, flecked with transparent salt and translucent potash 
crystals. The potash ore has an extremely bitter taste, which is 

readily distinguished from the bordering salt deposits. Generally the 

potash ore is seperated from the salt bodies by a thin (nominally one 

inch) layer of gray "mudn, which permits simple visual differentiation 

of the salt and ore bodies. 

The crystalline structure of the ore and surrounding over-burden 

results in limited stress on the nbackn (roof). floor and walls, so 

that roof falls are rare and the nrock-burstn phenomenon of hard-rock 

mines is non-existent. Old sections of the mine are observed to show 

bulging and sheet cleavage of the room walls. The strata is 

homogenous except for small random pockets of gas or water which are 

opened during the mining process. Generally these pockets are 

regarded as more of a nusiance than a hazard, although MSHA is 

currently (1981) conducting gas sample analysis to determine if 

combustible gases are present. Roof bolts and/or guniting is used in 

permenant underground facilities, such as near lifts. power stations, 

inventory and maintenance areas and sporadically along haulage and 

intake air rooms where pocketed areas have been uncovered or potential 

roof cleavage is suspected. Timbers and headers are not required. 

The mining process closely parallels that of coal mining with 

continuous miners or long-wall miners and belt haulage used throughout 

the basin. The mining installations include surface processing 

plants. which refine and bag the processed potash. Surface inventory 

storage facilities stock the refined product until it is shipped by 

rail or by trucks. 

The Kerr-McGee Hobbs Potash Facility is located in the number 10 bore 

region of the Carlsbad basin approximately thirty miles due East of 

Carlsbad, New Mexico. The facility has 350 empoloyees and operates 

eight working sections in each of three shifts and produces about 

nine thousand tons of ore per day. 

The mining operation is approximately 1800 feet in depth and is 

conducted on one level over an area 6.25 X 5.1 miles. The mine has 

two separate centrally located lifts for muck and men/equipment 

respectively. The North/Northwest section of the mine has been mined 

out and abandoned. Current and future mine development 1s ~roceeding 

Southwest and Northeast of the lifts. The major mine development is 

expected to occur East of the lifts. The mine operates six continuous 

miners with belt haulage from the faces to the production lift. Men 

and equipment are transported with electric nscootersn (built and 

maintained by the mine) and diesel trackless vehicles. 

The mine advancement consists of three parallel entries: the intake air 

entry (also normally used for vehicular transportation of men and 

materials and occasionally used for routing power cables); the belt 
entry (also normally used for cable distribution). and; the return air 

entry. The entries are uniformly 25 feet wide (the width of two 

continuous miner cuts) and 58" tall. (The mining seams are also 

usually 58" tall, although some intake entries are cut to be six feet 

tall, if they are expected to be used for transportation for several 

years.) The entries are spaced at 120' centers and are linked by (60) 

diagonal drifts ("breakthroughsn, designated by "BTn on the mine maps) 

at 160' intervals. The breakthroughs are sequentially numbered along 

straight slopes and permit rapid identifiers for locationing positions 

in the mine. The mine is also divided into nareasn which developed 

chronologically and were sequentially numbered as they were 

developed, so that contiguous areas do not necessarily have 

sequential designators. The areas are marked on the mine maps. As 

the mine advances. the breakthroughs between the belt and exhaust 

rooms are sealed to provide positive ventilation along the belt and 

up into the working sections. 

Secondary sets of three parallel entries are driven perpendicular to 

the main entries to support the punch mining operation of the 

continuous miners. The mining process is estimated to extract 

approximately 84% of the available ore body. The stability of the 

crystalline rock results in clean cuts by the continuous miners when 

the rooms are formed, so that the floor. "backn and walls of the rooms 

are flat surfaces meeting in defined corners. The ore body slopes at 

approximately a 3% grade from West to East. so the three parallel main 

entries are gently sloping long straight drifts, with slightly 

undulating floors. but uniform topology and with numerous periodic 

CrOSSCUtS. 

The continuous miners feed ore onto the conveyor belts which have belt 

power and transfer stations every 1500 to 2500 feet up to the 

production lift. The ore is transported to the muck lift which 

transports it to the surface. The men/equipment lift (called the 

supply lift) is within several hundred feet of the production lift and 

both lifts are controlled by a single hoistman. Ore is processed by a 

hot dissolution operation called nleachingn followed by fractional 

crystalization, which seperates the potash from the salt and other 

contaminants. 

2.2.4 AMAX LEAD CO. OF MISSOURI BUICK MINE 

The Buick mine is the largest single operation along the Viburnum 

trend in the St. Francis mountains in eastern Missouri. This largely 

North/South 40-mile long ,trend is in what once was a barrier reef. The 

ore body is located 500-1300 feet beneath the surface and is of the 

massive disseminated fill-in layer type. It is nominally 300-400 feet 

wide and 13-16 feet thick. but exceeds 100 foot thickness in places. 

The Buick mine working level depth is 1200 feet. The mineralization 
consists largely of galena (lead sulfide; 80% lead and 20% sulphur) 

and sphalerite (zinc sulfide; 67% zinc and 33% sulphur) with grades of 

6-8s (lead) and 2-31 (zinc) per unit weight of product. The Buick 

operation. an AMAX/Homestake partnership. has a nominal daily muck 

product output of 7000 tons, resulting principally in 130,000 to 

140.000 tons of refined lead per year, 56.000 tons of sulphuric 

acid, and a nominal amount of refined concentrate and silver. 

Lead/zinc mining in the area consists mostly of room-and-pillar mining 

with rubber-tired haulage to the central muck raise which feeds the 

crusher. The mine topobgy follows the lenticular ore bodies and. 

thus. mines are long and slender; typically several miles in extent. 

Typical dimensions are 35 feet wide by 13-16 feet high drifts with 

pillars on 60-foot centers. Due to the size of the Buick mine. the 

rubber tired haulage is supplemented with tracked haulage in a drift 

approximately 90 feet below the working level. In the haulage drift 

at Buick, the drift width is roughly 20-24 feet. 

The Buick mine is approximately four miles long and is divided into 

"North mine" and "South mine" legs with access shafts and service areas 

near the center. Mining operations are primarily at the mine 

ends with a little "clean up" mining at other locations. This mine is 

eight years old with a useful remaining life in excess of 30 years. 

The ore is mined in a balanced manner, with an attempt made to keep 

the ore grade nearly constant and not to mine just the richest ore 

first. On either side of the mine, ventilation shafts are located 

about a mile from the mine center. The air is pulled in at the 

mine center . where it is split and routed to the faces 

and then pulled out the ventilation shafts. The mine backbone 

power is 4160 VAC supplied in 3 grids and stepped down to a working 

voltage of 480 VAC. All mine wiring is run along the lower tracked 

haulage drifts and is elevated to the working product level adjacent 

to the ore passes (muck raises between levels). Going North. the AC 

power cables are bundled together and run on the back either along the 

left-hand rib or near the back center. Pager phones are generally 

located at each ore pass and at other key locations along the haulage 

level. The phone lines are also elevated to the product level near the 

ore passes. The phone line (a shielded twisted pair) is generally run 

along the center of the back. Air lines and water pipe in this area 

are bundled together and are run along the right-hand rib near the 

back. The back is sound, unbolted, and without mesh on the haulage 

level. Along the north mine leg, the haulage level gradually 

approaches the ore body on a 1-25 grade beyond the Northeast/Northwest 

haulage "Y". 

On the product level, the pillars remain integral and no retreat 

"pillar pullingn has begun. This activity will probably not be started 

for another 6-7 years. 
2.2.5 MAGMA COPPER CO. SAN MANUEL MINE 

The San Manuel mine is the largest copper mine in the U.S., 

efficiently extracting copper and molybdenum sulfide from the 

low-grade San Manuel ore body. The San Manuel mine operation employs 

in excess of 1000 men/shift with gross ore production between 60.000 

and 70.000 tons per day. The mining operation employs the block caving 

technique which is actively implemented on three levels (2075, 2375. 

2675 feet for haulage and 2015, 2315, 2615 product/grizzly levels). 

The ore haulage is largely via D.C. trolley trains to four (3A. 38, 

3C, 3D) product shafts for skipping to the surface. An additional 

three shafts at two locations are used to convey men, materials, and 

developmental rock extractions into and out of the mine. On each 

haulage level, the trains carry ore an average of two miles one-way 

from the ore raises to the dump points. 

All haulage drift segments contain the D.C. trolley wire located 

just off the back center with the ground return wire bus also 

running with the "hotn trolley wire and separated by about 10 inches. 

The ground wire branches to the track at periodic intervals of several 

hundred feet. Track construction/condition is excellent with a 

well-laid bed of wooden ties in ballast. Partcicular attention is paid 

to track electrical bonding; which, on the long haulage runs, is very 

good (electrical bonding near the grizzly ore chutes load points is 

poorer). Also located in the typical haulage drift is the audio pager 

phone line (generally in one of the back/rib corners). a 2400 VAC 

power cable and the usual air-line/water-line large pipe bundle. The 

ribs and back did not have metallic mesh covering. In the timbered 

drifts. the timbers were on both the ribs and the back spaced 

longitudinally on about 5-foot centers. 

2.2.6 HECLA MINING CO. CON-SIL MINE 

The Con-Sil is a recently re-opened mine, sponsored by a consortium 

of mining companies in the Silver Valley with Hecla as the operating 

company. This relatively small mine, located adjacent to the Sunshine 

and Silver Dollar mines, delivers in excess of 100 tons/day to a small 

mill conveniently located near the Silver Summit portal. 

Typical of operations in the Valley, the mining occurs below the 3000 

foot level employing the "stope and raise with sand backfill methodn 

along drifts running laterally away from the primary shaft stations at 

nominally vertically spaced 200 foot levels. The Con-Sil is presently 

pulling muck from the 4000-level via the main Silver Summit shaft. The 

intermediate Winze shaft between the 3000 and 4000-levels, that will 

permit mining on intervening levels, is being repaired following 

damage sustained during an approximate three year shutdown of this 
mine. The muck haulage occurs via battery operated trains on the lower 

haulage levels to muck pockets adjoining the main shaft. It continues 

via D.C. trolley-operated trains from the top station through the one 

mile portal drift to the mill dump point several hundred feet from the 

portal. 

The typical haulage drift in the Con-Sil has cross-sectional dimensions 

of about seven-foot head clearance from the floor-to-back and about 

six-foot width between ribs. The narrow gauge track (18 inches 

center-center with about 40 pound rail) is centered in the drift and 

well bedded. The water return ditch is also along the left-hand side 

facing the inby direction. The portal drift contains both a single 

cable bundle suspended from a messenger cable and the D.C. trolley 

bus. The operating level drifts, looking in the inby direction. 

contain an air line and water line bundle along and roughly vertically 

centered on the left rib above the return ditch. The cable bundle 

containing the 2400 and 440 VAC lines and the phone line is to the 

left-center of the back immediately below a pair of openwire 110 VAC 

lighting lines. and a sand line along the right rib suspended about 

one foot from the back. The back is generally bare, unmeshed, and 

unbolted. 

2.3 DEFINITION OF COMMUNICATIONS REQUIREMENTS 

With the exception of deep vein mines, which have logistic transport 

problems, and oil shale mines, whioh have massive ongoing operation 

coordination problems, the primary need for communications in 

metal/non-metal mines is associated with improving haulage operations. 

There is no belt haulage in these mines (except for the potash mine) 

and no dedicated haulage from each section all the way to the main 

dump point. Many of these mines have separate haulage and product 

vertical levels. Haulage communication needs are readily recognized by 

mine management. 

There is no hierarchy of phones in these mines as there are in coal 

mines. with the deployment of phones being dilute and with no standard 

requirement for a phone being located within a specific minimum 

distance from a working stope/face/etc.. Currently, there is generally 

no means to communicate from a central location to individual mining 

crews. Communications to such crews are not considered essential by 

many mines. Metal/non-metal mines share with coal mines the common need 

to locate key (and roving) supervisory or maintenance personnel. 

The following subsections present a summary of communication 

requirements for each visited mine identifying aspects where wireless 

communications could be intrumental in satisfying these requirements. 
2.3.1 OCCIDENTAL OIL SHALE LOGAN WASH MINE 

Although the Logan Wash mine is a horizontal entry "punchn mine, the 

practical operational facility at Cathedral Bluffs will entail a 

vertical entry shaft. In the initial mining operation before 

construction of the first retorts, wireless communications could be 

used in the shaft and along the developing drifts to coordinate these 

mining operations. 

Operationally. communications are required as part of both the mining 

and the process control functions. During retort construction. 

multi-level communications could greatly facilitate the mining and 

rubblization operations. Once the retorts have been fired. the 

communications requirements mainly fall in the area of monitoring 

transmission linkages for observation of sensors. This communications 

requirement will be very dense for the active retorts in monitoring 

temperature and off-gas conditions. 

2.3.2 UNITED NUCLEAR/HOMESTAKE PARTNERS SECTION 23 MINE 

The ore in muck pocket raises is pulled by motormen operating either 

the rubber tired dump trucks or the trains with ore cars. Currently 

there is no systematic means to tell the motormen that a particular 

raise is full and should be pulled. As a consequence, the operation of 

ore handling can become nmuck-boundn, where haulage (and even mining) 

must cease until the muck pockets are pulled and there is again a 

place to dump the ore. 

In the authors' experience, this is the first type mine using tracked 

haulage where a dispatcher and carrier phones were not used to improve 

the efficiency of haulage operations. In addition to the muck-pull 

dispatch, a central dispatcher can provides functions of traffic 

regulation and in-transit or roving personnel location. A wireless 

communication system providing the equivalent of carrier phone 

communications would be immediately beneficial to the mining operation. 

While there are phones within walking distance of the mining crews in 

the stopes, the relatively remote access of these phones relative to 

the ease of communication is not as flexible as it is in coal mines. 

This is especially true considering the "multi-tieredn haulage process 

in this type of mine. As part of a centralized wireless system for 

"on-the-moven communications, an entry into this wireless system from 

the fixed located stope areas could also prove beneficial. 

2.3.3 KERR-MCGEE CHEMICAL CORP. HOBBS POTASH MINE FACILITY 

The Hobbs Potash Facility mine has an operational mine pager phone 

system. which provides the primary communication link in the mine. 

Phones are located at working sections, belt stations, shops and 
office areas. The mine management estimates that this system provides 

approximately 20% coverage of the mine area. However, while the 

electric scooters provide rapid mobile transportation for key 

personnel. they also make location of those people very difficult. 

Communication with trackless vehicles is therefore, the most 

significant problem in the mine. For several years the mine 

successfully used mine carrier phones, operating at 88KHZ with 20 

watts of power into loop antennas, for wireless communication to the 

trackless vehicles. (The performance of the system was augmented by 

the routing of a dedicated wire along the "pinch wiresn on the belt 

system. so that signals could be coupled onto the dedicated wire and 

pinch wire pair.) However, difficulties in maintaining the system led 

to its abandonment. The mine currently uses commercial VHF 

"walkie-talkies" for communication up the production shaft and has 

purchased 61KHZ carrier phones adapted with couplers for communication 

from the hoist cages to the surface during maintenance operations. 

In general, the mine management indicated that as the mine expands 

further from the ,shafts. the communications problems will increase, 

and the desireability of having an operational wireless communication 

system capable of communicating with trackless vehicles will also 

increase. The management indicated that approximately fifty vehicles 

would be served by such a system and that the system would be 

economically feasible if the transceiver cost did not exceed $1500. By 

contrast. the mine investigated a UHF "leaky feedern system which was 

estimated to require $200,000 in cable plant alone. Presently, the 

mine may be characterized as recognizing a need and willing to install 

a wireless communication system. if the product were economically 

available. 

The operational requirements for such a system consist of the units 

having self-contained power and being able to communicate from any of 

the primary rooms to the office areas near the shafts. The system is 

not limited by transmit power, but is limited by cost as indicated 

above. With the present power distribution plant, the transceiver will 

always be located within one room of a power cable as long as it is in 

one of the main rooms normally used for vehicular transportation. The 

mine has also indicated that dedicated lines to augment the existing 

conductors could be inexpensively added to the existing cable plant by 

using nramsetn mounting of cable to the room "backn or walls (two men 

can run several miles of light wire per day using this technique). 

2.3.4 AMAX LEAD CO. OF MISSOURI BUICK MINE 

Existing communications at Buick are dilute and consigt only of pager 

phones. This was sufficient when the mine was small and travel to the 

face areas was not time consuming. But, there is currently no means to 

communicate with vehicular traffic or with roving maintenance or 
supervisory personnel. The mine now is growing rapidly which is 

increasing the North/South range rerquired to go from the faces to the 

central portal area. Mine-wide communications are desirable to 

facilitate operations in the following ways: 

1) use of a ndispatchern to regulate the timing of haulage 

traffic to the crusher 

2) vehicular communications between rubber-tired trucks on the 

product level and trains on the haulage level to convey that 

particular ore passes are full and should be pulled (perhaps 

via a dispatcher or a shifter) 

3) location of key maintenence or supervisory personnel (perhaps 

via a dispatcher) 

4) quick notification of any haulage or maintenance problems 

occurring or observed enroute where pager phones are not 

available. 

The mine wide nares coveragew communication needs can only be served 

efficiently by a wireless system. At a minimum, this system will 

require a radio and an antenna for each haulage vehicle plus a "fixedw 

station at a central "dispatchn location in the mine. The transmission 

media for this system must consist of existing mine wiring,and/or 

dedicated wiring to serve as a path for coupled "carrier currentn from 

the radio antennas. This type of communication, appropriate for Buick, 

will be summarized in the next section together with implementation 

possibilities. 

2.3.5 MAGMA COPPER COMPANY SAN MANUEL MINE 

The existing communications eminate from a dispatch location on each 

level and consist of both pager phone and carrier phone service. A 

separate carrier phone frequency is used on each production level: 115 

KHz on the upper level; 145 KHz on the middle level: and 190 KHz on 

the new lower level. There is currently a substantial amount of signal 

cross coupling between the levels. The typical MF spectrum contains a 

raster of harmonics and rectified/mixed cross products of these 

fundamentals and harmonics. 

Audio and radio communications on the grizzly level are currently 

limited to locations near certain ore passes and are dilute. 

With this as a basis, several communication-related requirements exist. 

These include: 
-improving the conventional carrier phone mode of 

communications to provide improved performance near 

the extremities of each haulage level 

-wireless communications on the haulage level to serve batteryoperated service vehicles and small locomotives so that 

"stingers" (which require vehicle stopping) are not needed 

in order to reach the dispatcher 

-wireless communications on the grizzly levels to serve battery 

operated vehicles with an overlay of the existing carrier 

phone frequencies on these levels to provide haulage coordination 

and to keep product level operations from becoming muck-bound 

-portable communications for maintenance/supervisory personnel 

tied into either the carrier phone channel or into a 

separate ~command/location~ channel to facilitate efficient 

operation of these personnel and to service special or emergency 

situations. 

2.3.6 HECLA MINING COMPANY CON-SIL MINE 

Existing communications consist of single-channel partyline 

magnetophones at major shaft stations and in the hoistroom. This 

system is typical of all mines in the valley. No communication is 

extended beyond the shaft stations and hoistrooms except for a phone at 

the junction of the 4000-level north crosscut and the 4000-level 

haulage drift near the Winze shaft location. 

With this as a basis, several functional communications possibilities 

exist for extending the capability of the present system. These 

include: 

- wireless communications between a desired fixed location 

and roving maintenance or supervisory personnel 

The fixed location could be in a shaft hoistroom or on a 

given operatiag level shaft station staging area, or in 

the mine office 

communication could be implemented as two-way voice or 

one-way paging. 

- wireless "alarm" communications from a fixed location 
into stope areas to alert crews to an impending health 

or safety problem 

- wireless communication between a fixed central location 

and other fixed locations where crews may be repairing a 

shaft or to a muck loading location 

2.4 OUTLINE OF PERFORMED WORK 

The performance of the work consisted of making swept frequency 

measurements in four bands from 0.2 - 1000 MHz at a fixed distance to 

select optimum frequencies. The optimum frequencies were examined in 

detailed CW tests at or near these optimum frequencies with respect to 

range and coupling parameters for the purpose of characterizing 

specific details of the transmission modes. This format ensured 

identification of major propagational effects with expedient 

convergence to specific investigation of the primary effects. The 

testing was typically performed in 2 1/2 days at each mine with an 

additional half-day spent discussing the tests and selecting test sites 

with the mine managment the day before going underground, and a 

half-day spent reviewing the priliminary test results after the final 

test day. A typical trip format was as follows: 

First Day- - arrive at the mine in early afternoon, review 

mine maps and select test locations; plan the 

first day's testing in the evening 

Second Day- - perform swept-frequency tests at a fixed range of 

(1st Day Undergound) about 300 feet at MF (0.2-1 MHz), HE (2-20 MHz), 

VHF (20-200 MHz) and UHF (200-1000 MHz) in one 

or two locations; test variations included: 

antenna vs current probe transmit excitation 

for MF & HF 

antenna orientations/polarizations in the 

drift and with respect to conductors at MF 

& HF 

Evenings were devoted to selection of optimum 

frequencies for CW testing. 

Third Day- - perform CW tests with test system and/or 

(2nd Day Underground) prototype MF radios from one or more fixed 

transmit locations to variable receiving locations 
Fourth Day- - complete or repeat any tests from the first two 

(3rd Day Underground) days and, if appropriate, perform an X-band 

microwave test 

IN EVERY MINE, MF INDUCTIVELY COUPLED TRANSMISSION PROVED TO BE THE 

MOST SIGNIFICANT. 

As the program progressed, the authors became more facile in 

recognizing any unusual phenomena and in arranging the tests to permit 

their investigation. In large part, the MF/HF tests proved to be tests 

of particular coupling phenomena to mine wiring. Test parameters in 

each of the swept ranges began to fall into bounded groups that were 

consistent from mine-to-mine. 

2.5 REPORT CONTENTS 

Section 1.0, Executive Summary. is intended as a stand-alone section 

providing an overview of all the test results and their relationship to 

practice, scientific knowledge advancement and to technology business 

development. This section also includes recommendations for further 

work. 

Section 3.0. Technical Approach, presents the characterization of the 

test system and its relationship to near-optimum hypothetical practical 

system embodiments. This section also presents a description of the 

test environments in each individual mine. Tables of test data 

reduction factors are provided. 

Section 4.0, Individual Mine Reduced Test Data, presents the 

significant reduced data from each individual mine Summary Data Report 

together with annotations and amplifying comments. 

Section 5.0. Presentation of Raw Swept-Frequency Data, presents all the 

original oscillographs from which the reduced results were derived. 

Together with data reduction factors given in Section 3.0. the reader 

can reproduce the reduced results: except as noted. 
2.6 DEFINITION OF REPORT TERMS, CONVENTIONS AND NOMENCLATURE 

Because this measurement program is closely linked to previous studies 

sponsored by the Bureau of Mines, the authors have elected to retain 

elements of the previously adopted nomenclature. In order to 

aleviate confusion which may arise from a strict technical 

interpretation of the terms, succinct definitions of several of these 

terms, reporting conventions and nomenclature follow. 

2.6.1 FREQUENCY RANGES 

The frequency range from 0.2 MHz to 1000 MHz has been allocated into 

the following bands which conform to natural limitations of the test 

equipment used in the field measurements: 

Medium Frequency Band The "medium frequency" band encompasses 

frequencies from 0.2 MHz to 1.0 MHz inclusive. The medium frequency 

band is designated by the abreviation "MF" for the sake of brevity in 

the report text and in the presentation of the data. 

High Frequency Band The "high frequency" band encompasses 

frequencies from 2.0~~z to 20.0 MHz inclusive. The high frequency 

band is designated by the abreviation "HF". 

Very High Frequency Band The "very high frequency" band, designated 

in the report as "VHF", encompasses frequencies from 20.0 MHz to 100 

MHz inclusive. 

Ultra High Frequency Band -- The "ultra-high frequency" band, 

designated in the report as "UHF", encompasses frequencies from 100 

2.6.2 LOOP ANTENNA ORIENTATIONS 

The MF and HF data was accumulated through the use of calibrated loop 

transmitting and receiving antennas. The antennas exhibit both a 

physical and an electrical planar geometry, which is used in this 

program to investigate distinct orthogonal propagational modes. 

Following are a list of orientation terms and abreviations adopted 

for the sake of brevity in the preparation of the text and data of 

this report. 

Coplanar Horizontal Magnetic Dipole The "coplanar horizontal magnetic 

dipole" antenna orientation consists of aligning an antenna in a 

vertical plane which intersects the geometric center of the other 

antenna. When only one antenna is used, such as in exciting adjacent 

conductors running along a drift, the antenna is aligned in a vertical 

plane which is parallel with the centerline of the drift. This 
orientation is designated as the "Coplanar HMD" orientation in this 

report. 

Axial Horizontal Magnetic Dipole The "axial horizontal magnetic 

dipole" antenna orientation (designated the "Axial HMD" orientation) 

consists of aligning an antenna in a vertical plane which is 

perpendicular to the line which intersects the geometric center of the 

other antenna. When only one antenna is used, the antenna is aligned 

in a vertical plane perpendicular to the drift centerline. 

Vertical Magnetic Dipole The "vertical magnetic dipole" antenna 

orientation (designated as the VMD orientation) consists of aligning 

the antenna in a horizontal plane, which intersects the geometric 

center of the other antenna, or is related to the height of the drift, 

if the other antenna is not present. 

2.6.3 MONOFILAR EXCITATION 

Previous studies in coal mines have resulted in an extensive body of 

knowledge relating to signal coupling onto and propagating along 

conductors in those types of mines. Unlike transmission lines, which 

have charterized parameters that sustain distinctive propagation modes 

for substantial distances, mine wiring is extremely variable and 

generally must be characterized empirically. The primary means of 

characterization which has evolved in the preceding studies, depends 

on the excitation of individual conductors or conductor ensembles by 

strong localized magnetic fields. Because the transmission properties 

of the conductor is unknown, and the return current path may be 

indeterminate, such excitation has been characterized as "monofilar". 

The usage of "monofilar" in this context relates only to the 

excitation of common phase currents in one or more conductors, which 

does preclude the existance of or mode conversion to differential 

propagation modes in other conductors. Indeed, with the widely 

varying topology of conductor types and cable plant configuratlons, a 

single mode would not be expected to exist without converting to other 

modes. "Monofilar" currents, therefore are used to describe currents 

which are generated in response to a particular excitation phenomena, 

with indeterminate return currents in other conductors or through the 

earth. 

In some isolated instances, "balanced" parallel conductors are 

encountered in which equal and opposite currents may be excited, in 

such symmetrical cases where differential currents are excited, the 

excitation mode is called "Bif ilar". The authors have attempted 

"Bifilar" excitation of such configurations as trolley power and 

ground (track) ensembles, but have found that the conductors were too 

unbalanced to generate significant differential mode currents. 
In general, most current excitation appears to be "monofilar", as used. 

in the context of this report, for both localized excitation currents 

and as the surviving transmission mode of MF signal propagation over 

long distances. 
3.0 TECHNICAL APPROACH 

Measurements were conducted in this program using a unique broadband 

swept-frequency test system. The use of this system permitted a 

spectral analysis of t r a n s m i s s i o n m o d e s in each mine from MF (0.2 MHz 

lower limit) through UHF (1000 MHz high limit) from which optimum 

frequencies were chosen for more detailed measurements/analysis. The 

test system is described in this section. 

Originally, all reduced test data was to have been normalized to sets 

of near-optimum practical system parameters so that actual system 

performance could be directly assessed. Following testing in the first 

mine, the MF and HF data was found to be so closely linked to 

particular coupling mechanisms that all further reduced data in these 

ranges was normalized to the test system parameters to facilitate 

understanding of these mechanisms. The VHF and UHF data continued to 

be normalized on a practical system basis. 

During the course of the program, particular MF/HF coupling phenomena 

were investigated via measurements and analysis. Additionally, 

theoretical and practical upper limits on MF/HF transmit performance 

were determined for practically-sized systems, which are described in 

this section. 

The results obtained in particular mines have been primarily attributed 

to the physical test environments encountered: electrical parameters 

of the geological strata, drift topology, drift cross-sectional 

parameters and details of mine wiring. Individual test system 

environments of the visited mines are fully described in this section. 

Significant transmission characteristics found in the individual mines 

during the swept-frequency tests were examined in detail using 

conventional continuous wave (CW) field strength meter techniques. 

Both swept-frequency and CW test system elements were calibrated prior 

to the first mine visit. The field strength calibration standard was 

a Fairchild EMC-25; which was calibrated by the Rockwell/Collins 

metrology lab test facility in Cedar Rapids prior to the first mine 

visit. 

3.1 TEST SYSTEM CHARACTERIZATION 

3.1.1 TEST SYSTEM DESCRIPTIONS 

The swept-frequency test system implementations are illustrated in the 

block diagrams of Figures 4 through 7. The system was generally 

deployed in a "typical" drift segment with a fixed transmit location 

and one or more fixed receiving locations at ranges between 150 and 

1000 feet; typically, 300-400 feet. 
FIGURE 4 

MEDIUM-FREQUENCYCMF) SWEPT-FREQUENCY TEST 

SYSTEM EQUIPMENT CONFIGURATIU4 

A/ 

SERIES RESONATING CAPACITOR 

A .-~D~FIEDsINGERANTENNA* 

RECE 1 VE 

- SYSTEM A 

t 

I 1 INVERTER^ 

124 VDC 1 12 VDC 

I 

OR 24 -----L"i_l VDC CELLS 

AC SUPPLY 

TEKTRON I x * 

--..- 7L5 OR 7L12 

PLASTIC 

TRIPUI A 1p&p@ 7- 5; ANN 

124 VDC 

1 s I-.J 

1 NVERTE 

BATTERY 

*Reference to soecific brands, eouiprnent, or trade names in this rt?Dort 

1s made to fact litate understandlnp and does not im~ly endorsement bv 

the Bureau of Mines 
FIGURE 5 

HIGH-FREQUENCY(HF1 SWEPT-FREQUENCY TEST 

SYSTEM EQUIPMENT CONFIGURATION 

MOD1 F I ED S l NGER ANTENNA * 

WAVETEK 

200 1 

AC 

POWER 

METAL TRl WD l NVERTER 

I 

(24 VM: 1 12 VM: 

I ----- 

OR 24 VCC 

Ac SUPPLY 

\I/- Inn 

I 1 SPECTRUM ANALYZER 

BATTER 1 ES 

l NVERTEF 

*Reference to specific brands, eauiament, or trade names in this reaort 

is made to facllttate understandtna and does not imoly endorsenent by 

the Bureau of Mines 

- 58 - 
FIGURE 6 

VERY-HIGH-FREQUENCY(VHF1 SWEPi-FREQUENCY TEST 

SYSTEM EQUIPMENT CONFIGURATION 

EMX) 3104 BlCONE ANTENNA* 

TRANSMIT 

L --- 

24 VCC 

AC SUPPLY 

F7 ' - CELLS 

/ EX0 3104 Bl CONE ANTENNA * 

RECE I VE 

ERW ANALYZER 

I ""/\ WLEIN 

SPECTRUM 

ANALYZER I NVERTE 

*Reference to Soecific brands, eauipment, or trade names in this reoort 

is nade to facilitate understandino and does not imolv endorsement by 

the Bureau of Mlnes 

- 59 - 
FIGURE 7 

ULTRA-HIGH-FREQUENCY(UHF1 SWEPT-FREQUENCY TEST 

SYSTEM EQUIPMENT CONFIGURATION 

/ DORNE 6 MARGOLI N AR- 122' LOGPERIODIC ANTENNA 

- RECE I VE 

- SYSTEM 

J 

PLAST l C 

I AC 

TRlWO 

I 

I P3WER 

1 NVERTEF 

I 

---- 

OR 24 VM: CELLS 

AC SUPPLY 

DWJJE L MARGOL I N AR- 122' / LOGPERI'ODIC ANTENNA 

TEK-RONI X* 

PREAMP ANALYZER 

AC 

MOWLE' IN 

ANALYZER 

'Reference to soecffic brands, eaulonent, or trade names in this repor? 

is made to facllrtate~nderstandlnn and does not imly endorsement bv 

the Bureau of t8ines 
The key elements in the swept-frequency system were Tektronix* 7L5 or 

7L12 spectrum analyzer modules used as receivers in a Tektronix* 7603 

storage oscilloscope mainframe. The analyzers operated asynchronously 

with respect to the swept frequency output of one of two Wavetek* sweep 

generators in MF, HF, VHF and UHF bands. Data was recorded on 

oscillographs. Particular lists of equipment and test system 

parameters follow: 

Medium Frequency (MF) Tests (nominally 0.2-1 MHz) 

Transmit System: 

- Wavetek* Model 114 sweep signal generator 

switch 'ffw, X3, XI set to XI 

frequency. Hz set to lOOK 

sweep mode set to cont. w/sweep 

(align red k black lines) 

slope/level set to -1, red line "upn 

sweep rate: black on 0.1 

red on 1 

frequency dial set to 0.5 

amplitude set to minimum value 

- ENI* 300P power amplifier 

1-watt output into 50 ohms 

- modified Singer* shielded loop antenna broadly series 

resonated to 0.65 MHz, area = 0.73 square 

meters 

or 

Stoddard* current probe 

- batteries and inverter as shown in Figure 4. 

Receive System: 

- Singer* NU-25 loop antenna set to band-1 

- Hewlett Packard* 08640-060506 low noise preamp 

(33 dB gain in MF band) 

Reference to specific brands, equipment, or trade names in this 

report is made to facilitate understanding and does not imply 

endorsement by the Bureau of Mines. 
- Tektronix* 7L5 spectrum analyzer 

500 KHz dot frequency 

100 KHz/division 

30 KHz resolution 

10 dB/division log amplitude 

or 

Tektronix* 7L12 spectrum analyzer 

100 KHz/division 

30 KHz resolution 

10 dB/division log amplitude 

trace start marker at left graticule line 

High Frequency(HF1 Tests (nominally 2-20 MHz) 

Transmit System: 

- Wavetek* Model 2001 sweep signal generator 

output set to -10 dBm 

mode switch on S/S 

band-1 

sweep time set to 1:l 

carefully adjust frequency limits 

- ENI* 300P power amplifier 

1-watt output into 50 ohms 

- modified Singer* shielded loop antenna with 100 feet of 

RG-8 cable serving as a delay line with resonant peaks 

at 2.0, 4.4. 7.9. 14.4, 18.0 MHz 

0 r 

Stoddard* current probe 

- batteries and inverter per Figure 5. 

Receive System: 

- Singer* NM-25 loop antenna set to band 4 

- Hewlett Packard* 08640-060506 low noise preamp with 

gain as shown in Figure 5. 

Reference to specific brands, equipment, or trade names in this 

report is made to facilitate understanding and does not imply 

endorsement by the Bureau of Mines. 
- Tektronix* 7L12 spectrum analyzer 

2 MHz/division 

300 KHz resolution 

10 dB/division log amplitude 

trace start marker at left graticule line 

Very High Frequency (VHF) tests (nominally 20-200 MHz) 

Transmit System: 

- Wavetek* Model 2001 sweep signal generator 

output set to -10 dBm 

mode switch set to S/S 

band 1 

sweep time set to 1:l 

carefully adjust frequency limits 

- ENI* 600L or 600P power amplifier 

1-watt into 50 ohms 

- EMCO* 3104 biconical antenna 

broadband 

- batteries and inverter as shown in Figure 6. 

Receive System: 

- EMCO* 3104 biconical antenna 

broadband 

' - Tektronix* 7Kll CATV preamp 

set to 0 dBmV 

- Tektronix* 7L12 spectrum analyzer 

20 MHz/division 

3 MHz resolution 

10 dB/division log amplitude 

trace start marker at left graticule line 

Reference to specific brands, equipment. or trade names in this 

report is made to facilitate understanding and does not imply 

endorsement by the Bureau of Mines. 
Ultra High Frequency (UHF) Tests (nominally 200-1000 MHz) 

Transmit System: 

- Wavetek* Model 2001 sweep signal generator 

output set to -10 dBm 

mode switch set to S/S 

band 1, band 2 (500 MHz crossover) 

(2 oscillographs required) 

sweep time set to 1:l 

wide-open band limits 

- ENI* 600L or 600P power amplifier 

1-watt into 50 ohms 

- Dorne & Margolin* ARl22 log periodic antenna 

broadband 

- batteries and inverter as shown in Figure 7. 

Receive System: 

- Dorne & Margolin* AR122 log periodic antenna 

broadband 

- Tektronix* 7Kll CATV preamp 

set to 0 dBmV 

- Tektronix* 7L12 spectrum analyzer 

100 MHz/division 

3 MHz resolution 

10 dB/division log amplitude 

trace start marker at left graticule line. 

Continuous wave tests used the same transmit system as the 

swept-frequency tests with frequency generators operated on a CW basis 

or. alternatively, Collins* MF 520 KHz 1-watt portable radios and tuned 

loops. The CU receiving equipment consisted of the Singer* NM-25 field 

strength meter for MF/HF tests and the Fairchild* EMC-25 field strength 

meter for VHF/UHF tests. The MF/HF receiving antenna was a standard 

Singer* calibrated loop. The VHF/UHF receiving antennas were biconical 

or log perio'dic antennas. The X-band microwave test set-up, 

illustrated in Figure 8, used a .Microwave Associates* 86656CM source 

and a Singer* NM-65 field strength meter each operating with Narda* 

horn antennas. 

Reference to specific brands, equipment, or trade names in this 

report is made to facilitate understanding and does not imply 

endorsement by the Bureau of Mines 
FIGURE 8 

MICROWAVE CW TEST SYSTEM EQUIPMENT CONFIGURATION 

MICROWAVE ASSOCIATES* 

86656CM X-BAND SOURCE 

RECE I VE 

SYSfEM 

PLAST I C 

'Reference to s~eclflc brands, eoulpnent, or trade names in this re~ort 

Is made to facllltate understanding and does not lm~ly endorsement by 

the Bureaa of Mlnes 

- 65 - 
3.1.2 TEST AND PRACTICAL SYSTEM CHARACTERISTICS 

The characteristic test system parameters are the transmit current 

moment and conversion factors relating received signal levels to 

incident magnetic and electric field strengths. Transmit moment and 

receive signal sensitivity parameters are used to perform data 

normalization for practical operating systems. A modified set of 

correction factors can be used for normalization of the test system 

measured data to practical systems. 

The most appropriate representation of current moment is the 

quasi-static purely geometric limit of INA (product of current, number 

of loop turns and the loop area in square meters) for loop antennas, 

and Ihe (product of base current and effective height, he) for 

dipole/monopole electric antennas. For the quasi-static induction 

field case, these representations are equivalent. These quasi-static 

terms must be modified to represent the radiation field moments at 

substantial distances from the antennas where, to achielve equivalence 

with I&. the magnetic current moment must be multiplied by 2 times pi 

times the inverse of the signal wavelength in meters. 

For the test system, the geometric current moments have been measured 

as part of the system calibration process. For practical systems, the 

current moments have been calculated for man-carried and/or vehicular 

applications involving a nominal 0.2 square meter loop and a 0.375 

meter high VHF or a quarterwave UHF whip assuming 1-watt of available 

power equivalent to that from the test system. 

Loop transmit moments (INAS) were computed as a composite of multi-turn 

(2-10 turn) loop parametric data derived from a proven multi-turn loop 

design algorithm previously presented by the author in the final report 

of Contract 50395072, Wireless Communications for Trackless Haulage 

Vehicles. Computed data for a 50 ohm 1 watt source 

exciting the antennas through a single-pole matching network is 

presented in Figure 9. Readily available impedance data was used for 

the whip antennas with computations for 1 watt from an impedance 

matched 50-ohm source shown in Figure 10. The loop data does not 

reflect either the practical upper limit for single-pole-tuned 

operation or the theoretical upper limit derived on a stored energy 

basij. 

The receiving system correction factors (added directly to the dBm 

signals shown on the spectrum analyzer to determine the magnetic or 

electric field strength) are the composite sum of: 

(1) the calibrated receiving antenna factor in dB. 

(2) the measured receiving system preamplifier gain in dB 

(3) 107 dB dBm-dB V conversion, 

(4) and. for determination of the magnetic fields. -51.15 dB 

uVolt/m-uAmp/m conversion factor for the intrinsic free 

space impedance. 

em 2 s 

a 

LOW 

I3 

>LO 

aoa 

- 

W- U) 

4 2 

a -I2 3 <ZS - OW+ 

L -C 

t z % 

SLIP-+ 

I a 

033 

WI toa22 

OW4 
Correction factors for MF/HF test and practical swept and CW systems 

are given in Table 2. Corresponding VHF/UHF correction factors are 

given in Table 3. In the individual reduced mine data of Logan Wash 

Mine, United Nuclear Section 23 Mine, and Kerr- McGee Hobbs Potash 

Mine, some of the correction factors varied from those given in these 

tables due to replacement of the transmit test power amplifier and due 

to the erroneous assumption that the gain of the preamps was 

independent of frequency. Correction factors and transmit coupled 

current values appropriate for use with the Stoddard current probes 

-are given in Table 4. 

Geometric current moments for the practical and test systems are given 

in Figure 11. This data may be compared with values for comparable 

radiation current moments given in Figure 12. For evaluating the 

predicted performance of npractical systemsn, computed receiving 

system sensitivity levels (based on the thermal noise limits of the 

loops) are given in Figure 13. 

3.2 CATEGORIZATION OF TESTS & TEST ENVIRONMENTS 

3.2.1 OCCIDENTAL OIL SHALE LOGAN WASH MINE 

First Day Tests 9-25-80 

The first day of testing was comprised soley of swept-frequency 

measurements. The transmitting signal sources were located at the end 

of the L-700 drift (South) under a non-roof-bolted section of the mine 

that was free of conductors for a distance of 50 or 60 feet in front of 

the transmitter. The transmitter was placed at the drift center and the 

receiving antenna was also placed in the drift center at a distance of 

240 feet (nearly opposite the entry to Retort 16). Following these 

tests, the receiving location was moved closer to the transmitter to a 

range of 120 feet where the measurements were repeated. Beyond the 

50-60 foot range (entrance to inventory storage area), conductors in 

the drift extended in the inby direction. Over the test range, the 

roof height varied between 10 and 20 feet and the drift width varied 

between 30-40 feet. The geometry of these tests is illustrated on the 

mine map of Figure 14. 

Second Day Tests 9-26-80 

On the second day, CW VHF and UHF tests with range along the L-700 

drift were performed at test frequencies of 80, 150, 500. and 800 MHz. 

The transmiter location was the same as that used the first day for the 

swept-frequency tests. 
TABLE 2 

MF d HF MAGNETIC FIELD STRENGTH CORRECTION FACTORS 

FREQUENCY (Mi21 

0.2 

0.25 

0.35 

0.45 

0.55 

0.65 

0.75 

0.85 

0.95 

2.0 

4.4 

7.9 

11.2 

14.4 

18.0 

TEST SYSTEM 

SWEPT (DB) CW(DB) 

PRACTICAL SYSTEM 

SWEPT(DB) CW(DB) 

TABLE 4 

MAGNETIC FIELD STRENGM DATA CORRECTI3N FACTORS 

FOR USE WITH STODOARO CURRENT PROBE 

FREQUENCY (MHz) FACTOR( DB) 
a 

80 NI 1II = VNI lN3WOW lN3tltlfl3 NQI13naNI 31tJUW03E) 



Additionally, as the transmit location was in a conductor-free area. MF 

CW tests were performed at frequencies of 250. 650, and 1000 KHz. The 

test geometries for the second day of testing are shown in the mine 

maps of Figures 15 and 16. 

Third Day Tests 9-27-80 

MF CW tests of loop-excited and current-probe-excited monofilar 

transmission modes were performed during the third day. For the 

antenna excitation test, the transmit loop was placed in the drift 

center in the coplanar HMD orientation. The probe-excited 'tests were 

conducted with the probe coupled to the phone line near Retort X6 where 

the access to the middle level was located. 

Additionally, a CW microwave test was conducted in the conductor-free 

area of the L-700 drift. This test was conducted along a straight line 

and also around a corner employing the 4-foot plane reflector. 

Geometries of the third day tests are given in the mine maps of 

Figures 17 and 18. 

3.2.2 UNITED NUCLEAR/HOMESTAKE PARTNERS SECTION 23 MINE 

All testing, except for the MF CW measurements on the phone line, was 

conducted in two areas of the mine. The primary test area was along the 

Wagner 650 level drifts. The secondary test area was on the 650 tracked 

level near the portal shaft. The MF CW tests were conducted using a 

current probe on the phone line at the primary Wagner area transmit 

location with the receiving NM-25 field strength meter being removed as 

far as the 726 level 58 East track and the 780 drift track. The 

specific test locations are depicted on the mine maps of Figures 19 

and 20. The CW test locations are designated by letters A through I. 

The primary and secondary transmitting and receiving locations are 

designated by T and R respectively. 

Data taken in the primary Wagner test area for VHF CW tests and MF CW 

tests coupled to the 480 VAC line at test locations 0 through 8 are 

shown in Figures 21 and 22. The microwave range tests were conducted 

between sites 0 and 1; the microwave depolarization tests were 

conducted between T and R, with the reflector placed at R and the 

measured signal being received after reflection in the short drift to 

the mining level raise. 

First Day Tests 11-28-80 

The first day of testing consisted of conducting all swept-frequency 

tests. 



FIGURE 18 

OCCIOENTAL OIL SHALE LOGAN WASH MINE 

CURRENT PROBE EXCITED MNOFILAR EODE 

650KHZ FIELD STRENGTH MEASUREFENT LOCATIONS 

. . 

FIGURE 20 

UNITED NuCLEAR/HOMESTAKE PARTNERS SECTION 23 

MINE MAP SHOWING MF COUPLED PHONE LINE RX 

LOCATIONS ( MF COUPLED PROBE AT TX LOCATION 

IN WAGNER DRIFT 

SCALE: I INCH = 200 FEET 
UNITED NUCLEAR/HOMESTAKE PARTNERS SECTION 23 

MINE MAP OF WAGNER AREA SHOWING PRINCIPAL 

SWEPT FREQUENCY TX 6 RX LOCATIONS, PUS RX 

, LOCATIONS FOR CW VHF TESTS 6 MF COUPLED 

*"' POWER LINE TESTS 

SCALE: I INCH = 40 FEET 

! 

- 84 - 

-- Second Day Testq _-1.?29-8_0_ 

Testing the second day consisted of conducting all CU tests, with the 

exception of the microwave tests. 

Third Day Tests 11-30-80 

The third day of testing consisted of conducting the microwave tests. 

The swept-frequency tests were conducted along an approximate 180-foot 

throw in the presence of a 480 VAC line and a water line strapped to a 

lathe fence which was on the roof and extended down the sides of 

each rib comprising three overlapping sections in cross section 

running along the drift. Detailed profiles of the swept-frequency 

range geometry, drift cross sectional geometries and conductor 

topologies are illustrated in Figure 23. 

3.2.3 KERR-MCGEE CHEMICAL CORP. HOBBS POTASH FACILITY MINE 

First Day Tests 12-9-80 

The first day of testing consisted solely of swept frequency 

measurements. The transmitting signal sources were located in Area 140 

at breakthrough 3 of Room 245 (see Figure 24). Breakthrough 3 has 

been extended 800' and will be an active mining section when the 

mining operation retreats back to that point in several years. The 

"back" was approximately seven feet at the breakthrough intersection. 

but reduced to about 65" after the second breakthrough. Room 245 was 

observed to be free of conductors except for a low voltage (110 VAC) 

power cable and a pair of conveyor belt pinch wires which ran along 

the Northern wall and center of breakthrough 13. The pinch wires were 

approximately 20AWG bare steel wires seperated by about four inches 

and mounted on insulated standoffs from the room "backn. The pinch 

wires were observed to have open-ended terminations and ended before 

the fourth breakthrough of the room. The small power cable was 

observed to leave the room at the second breakthrough (between the 

first and second measurement sites) and its termination is unknown to 

the author. The first test site was selected mid-room and about 150' 

feet from the transmitting site. 

The swept-frequency tests were all antenna-excited except for one MF 

test where the Stoddard current probe was placed around the low voltage 

power cable at the transmit site in breakthrough 63. 

Second Day Tests 12-10-80 

The second day of testing began with a measurement of continuous 
UNITED NUCLEARMOMESTAKE PARTNERS SECTION 25 

MINE WAGNER DRIFT CROSS-SECTION RFTWFFN . . -- ...--.. 

PRIMARY SWEPT FREQUENCY TX AND RX LOCATIONS, 

FLOOR ASSllMD TO BE FLAT 
AREA 140 
wave signal propagation at medium frequencies in the same location of 

Area 140 as the first day tests (see Figure 25). Signals were 

transmitted at 250KHZ. 650KHZ and 950KHZ and measured as a function of 

distance and antenna orientation to the end of breakthrough #3. Next, 

a test to evaluate the UHF waveguide propagation mode was conducted in 

room 225 along the conveyor belt route as shown in Figure 26). The 

transmitter was set up near the center of the room with the antenna 

oriented to excite the horizontally polarized propagation mode. Field 

strength measurements (with a horizontally polarized receivig antenna) 

were then conducted at two freqencies (650MHZ and 900MHZ) as a 

function of distance from the transmitter site along room 225. 

Later in the day, due to the generous cooperation of the mine in 

providing a "scootern to the measurement team, a test to determine the 

extent of carrier coupled signals along the mine's primary conductors 

was conducted. The test consisted of locating a transmitting loop 

antenna at breakthrough t3 of room 225 (the conveyor belt room) in 

close proximity to conductors located along the West wall of the room, 

and conducting field strength measurements of the transmitted signal 

along the conductor routes in both directions from breakthrough #3. 

The transmitter was excited with a 650KHZ signal, which had been found 

to be in the optimal coupling frequency range in the previous tests. 

The test sites are shown in Figure 27. Test measurements were 

conducted with the receiving antenna in close proximity to any 

conductors within reach (approximately 0.6 meters). Conductors were 

in close proximity in all measurements except at points 14, 15. 16. 

18, 19 and 20. 

Third Day Tests 12-1 1-80 

A 10 GHZ transmitter was placed in room 126 West near breakthrough 112 

(see Figure 27). Line of sight field strength measurements were made 

as a function of distance along the room (in a Westernly direction). 

The measurement area consisted of a low (58") back with smooth room 

surfaces and a West to East grade of 3%. A depolarization test was 

also conducted to measure the ability of a reflector to achieve its 

theoretical cross-sectional gain in the beam collimation region when 

acting as a 45 degree reflector. The tests were concluded at 

breakthrough 614, because no detectable signal was located at 

breakthrough t15. The grade of the floor apparantly resulted in 

enough offset in the beam projection so that a line of sight 

transmission path did not exist. 

3.2.4 AMAX LEAD CO. OF MISSOURI BUICK MINE 

The mine testing was all performed in the lower level tracked haulage 

drift in the North mine. A summary of the testing follows: 
AREA 140 

FIGURE 25 

KERR-MCGEE HOBBS POTASH FAC I L I TY 

AREA 140 MINE MAP SHOWING MEDIUM 

FREQUENCY CONTINUOUS WAVE FIELD 

STRENGTH MEASUREMNT LOCATIONS 

(250KHZ, 650KHZ AND 950 KHz) 

SCALE 
FI GURE 26 

KERR-FKGEE HOBBS POTASH FAC I L I TY AREA 140 

ROOM 225 MINE tdAP SHOWING UHF COHTINUOUS WAVE 

F l ELD STRENGTH LlEASUREtlENT LOCAT l ONS (6OOlnHZ 

AYD 900WZ) 

First Day fests 2-3-81 

Swept frequency tests over the MF.HF,VHF and UHF bands were performed 

with the transmitter located at the North mine Northeast/Northwest Y. 

All of the tests were performed with the receiving location at the 064 

ore pass, 390 feet away from the transmitter. MF and HF tests were 

repeated at the 049 ore pass 1290 feet away from the transmitter. 

These test locations are illustrated on the mine maps of Figures 28 

and 29. 

Second Day Tests 2-4-81 

Demonstration Cbl tests were performed using the Collins USBM prototype 

MF radios with the received field strength measured at each location 

using the Singer NM-25 field strength meter. The base station was 

located in the foreman's shack near the mine center. The base station 

transmitter was loop coupled successively into the pager phone line 

and into the dedicated wire which had previously been installed for 

adapted carrier phone tests. Voice communication and measurable field 

strengths were determined at a sequence of locations corresponding to 

the ore passes and the Y out as far as station 141. The test locations 

are depicted on the mine maps of Figures 28 and 29. 

Third Day Tests 2-5-81 

Swept frequency tests were performed over the MF band only using the 

low frequency 7L5 spectrum analyzer. The transmitter was set up in the 

foreman's shack near the mine center and was loop-coupled into the 

dedicated wire. Receive signal oscillographs were taken at the same ore 

pass stations used for the previous days testing. 

The first days' MF/HF testing was found to be unrepresentative of the 

the general mine characteristics determined in later tests due to 

anomolies in the phoneline/dedicated wire and in the AC power cables, 

taken as monofilar conductors, in the region of the Y. The rapid signal 

attenuation with increasing frequency in the MF band was first 

correctly observed during this testing, which initially indicated that 

the lower MF frequencies were optimum. The swept frequency data was 

too dilute to permit impedance characterization of the monofilar line 

structure near the Y. 

During the Thursday swept frequency tests, a spectrum analyzer 

malfunction made the oscillographs unusable for reproduction in this 

report; consequently, they are not shown. The data redu.ced from these 

oscillographs is given in total. 

In the vicinity of the Y, the principal return path for the phone line 
4/0 5KV CABLE 

SCALE: I INCH = 500 FEET 

.. .-, - 

go~~ ~mTtiAND SOUTH CAB1 Fs 

~€40 END AT THIS JUNCTW 

ARE NOT INTERCONNECT^ - 

MAP OF NORTH MINE OF AMAX BUlCK MINE 

SHOWING TRANSMIT RECElVf LOCATIONS 

USED DURING Wlm TRANSMIT 

RANGE TESTS SHOWN 
STA 129 

LP 4588 

PMPC B 

(122-N) 

HVSW GE 

SCALE: 1 INCH = 500 FEET 

'ENT DRIFT 

23 24 

FIGURE 29 

MAP OF NORTH MINE LEG OF AMAX BUlCK MINE 

SHOWING TRANSMIT AND RECEIVE LOCATIONS 

USED WRING MEASUREMENTS WITH TRANSMIT 

LOCATION FOR SWEPT-FREOUENCY TESTS SHOWN 

049 ORE PASS 
and dedicated wire (ostensibly acting as a common conductor) was the 

power cable bundle some four feet away. The field fall-off law was 

determined in this region (illustrated in Figure 6) with the range 

exponent determined to be 1.26. 

3.2.5 MAGMA COPPER COMPANY SAN MANUEL MINE 

All testing was conducted on the 2375 level, which is illustrated in 

Figure 30 with all the test locations on the Measurement Traverse. The 

drift cross section in the long haulage runs is a combination of 

timber ladder drift and concrete drift construction (both shown in 

Figure 31). 

First Day Tests 3-31-81 

Swept-frequency tests over the MF.HF,VHF and UHF bands were performed 

on the car-cleaner track. This drift contained essentially no 

conductors other than the track. The transmit location was set up in a 

timbered section of the drift. The receive location was set up 243 

feet away in a concrete drift section. HF and HF data was taken for 

all three principal polarizations of the loop antennas. The horizontal 

magnetic dipole (HMD) orientations were set up in the drift center with 

the antenna 1.1 meters above the track. The transmit vertical magnetic 

dipole (VMD) orientation loop plane was positioned 1 foot (0.3 meters) 

above the rails. This geometry is illustrated in Figure 32 . The 

received VMD was alternately positioned 1 foot, 4 feet and 8 feet 

above the rails. 

The normal deployment of the VHF and UHF antennas in both vertical and 

horizontal polarizations was made in the drift center. No signal was 

received at VHF in the first location, so the receiving location was 

repositioned in a timbered drift section 111 feet from the transmitter. 

A prototype MF radio was installed on a trolley-operated locomotive 

for long-term qualitative testing by mine personnel in comparison with 

existing carrier phone equipment. This radio employed a 145 KHz 

passband filter to minimize receiver desensitization. 

Second Day Tests 4-1-81 

A prototype base station MF radio was set up in the locomotive machine 

shop radio shack and another prototype radio with a 1 uV sensitivity 

and a 145 KHz passband filter was set up on a battery powered 

locomotive with a prototype vehicular antenna. The spectrum analyzer 

was set up in a man car behind the locomotive to permit quantitative 

signal and noise measurements on the base-vehicle linkage. A retuned 

Collins portable antenna was used with the spectrum analyzer. Talking 

tests were conducted around the loop traverse via panel 17, as 
I 

i 

! 

! 

.,. .-,,.-L- - .~ ~ ~ ~~~ ~ ~~. ..~ ~ 

I > -: .. --- --- 

U3 

.I 

I 

5-SHAFT TllRFJO ~ .. 

SCALE: 

Fl GURE 30 

THE MEASUREMENT TRAVERSES FOR EVALUA

THE MSA 1680' CARRIER :PHONE PER~~RM

, LOCOMOTIVE MACHINE SHOP 6 

RADIO SHOP TX LOCATION 

*Reference to speciflc brands, equipment, o

repnr+ 1s Mde to facllltate understanding 

endorsement by the Bureau cf Mlnas 
FIGURE /31 

DRIFT CROSS-SECTIONAL GEOMETRIES ENCOUNTERED DURING SWEPT-FREQUENCY 

MASUREMENTS IN ME MAGMA COP b ER CO. SAN MANUEL MINE CAR-CLEANER DRIFT 

. . Standard 

Grade Line e 

Dedpt. Track I \ Compl. Track 4 'BauaatbPlowtlo 

TRANSMIT LOCATION CROSS-SECT1 N FOR ALL FREQUENCY RANGES AND 

RECEIVE LOCATION CROSS-s e cTloN FOR vHF MEASUREMENTS 

I4' Ballast blow tie 

RECE l VE LOCAT l ON CROSS-SECT1 CN FO~ ALL FREQUENCY RANGES EXCEPT VHF 
FIGURE 32 

TRACK COUPLING GEOMETRY FOR SWEPT-FREQUENCY 

MEASUREMENTS IN MAGMA COPPER CO. SAN MANUEL 

\!IN€ 

COPLANAR HM) LOOP ORIENTATION 

I/ 

VMO LOOP ORIENTATION 
illustrated on the mine map of Figure 30. Quantitative tests were 

performed at the test locations listed in Table5. 

Third Day Tests 4-2-81 

The Collins 0.2 uV-front-end prototype base transceiver and the 

vehicular radio were set to 520 KHz, similar to the preceding day, 

except that a vehicular radio with a 90 uV sensitivity was used 

without a passband filter. The vehicular antenna tuning was changed 

with an interchangable 520 KHz head replacing the 145 KHz head used on 

Wednesday. This time, the spectrum analyzer was set up in the radio 

shack to permit quantitative testing on the vehicle-base linkage. The 

spectrum analyzer was coupled with a current probe to one of the 

coaxial leads feeding the Collins base station transceiver. The fixed 

location of the spectrum analyzer permitted a more detailed assessment 

of signal levels than did its usage on the man car the previous day. 

Voice tests were again performed around the panel 17 loop traverse, 

and quantitative tests were performed at the test locations given in 

Table 5. 

3.2.6 HECLA MINING CO. CON-SIL MINE 

The in mine testing was performed on the 3000-level except for radio 

nvoicen tests in the cage and near the 2500 and 4000-level shaft 

stations. Due to substantial cooperation from the mine, 5-6 hours were 

available Oon stationn each day for tests, and all of the tests were 

completed in 2 days rather than the alloted 3 days. A chronological 

summary of the testing follows. 

First Day Tests 6-2-81 

Swept-frequency tests on the' MF, HF, UHF and VHF bands were conducted 

in the 3000-level North Crosscut with the transmit set up near the 

shaft station in the pipe shop toward the South side of the mine. All 

data was taken on a 429 foot path with the receiving locations just in 

front of the first active set of air doors. The VHF and UHF data was 

repeated at a closer range of 195 feet with the receiving location at 

the first cut to the left in the outby direction. The antenna 

orientations and locations employed in the drift cross section 

geometry are given in Figures 33 and 34. The swept-frequency test 

locations are shown in Figure 35. 

Second Day Tests 6-3-81 

All range tests at MF frequencies and the X-band test were conducted 

on the second day. The locations for the MF range tests are 

illustrated in the mine map of Figure 36. Specific ranges from the 

fixed transmitting location to these test locations are given in Table 
TABLE 5 

DISTANCES TO LOCATIONS ALONG THE PEASUREMENT TRAVE.RSE 

ON THE 2375 HAULAGE LEVEL 

LOOP DISTANCES STARTING LOOP DISTANCES STARTING 

LOCAT I ON ON SOUTH HALILACX ( FEET) ON NORTH HAULACE( FEET) 
/ llOVAC OPEN WIRE 

LIGHTING LlNE 

WATER 

/' CABLE BUNDLE 

2400 VAC 

440 VAC 

PHONE LlNE 

WATER LlNE 6 AIR LlNE 

24-IN. SAND LlNE 

1-FOOT FROM BACK 

BEWED !&IN C-C 

TRACK 

FIGURE 33 

DRIFT CROSS-SECTIONAL GEOMETRY VIEWED IN THE IUBY 

DIRECTION SHOWING HMD TEST ANTENNA LOCATIONS 

HECLA CON-SIL MINE 

MIDDLE H(C8) = I(DB) - 26.6 DB 

BOTTOM H(DB) = I(C81 - 39.0 DB 
1 1 OVAC OPEN W 1 RE 

LIGHTING LINE 

CABLE BUNDLE 

PHONE LI IE 

WATER LlNE 6 AIR LlNE 

2f-IN. SAND LlNE 

1-FOOT FROM BACK 

1.70 METERS 

BOTTOM - 

BEDDED I&IN C-C 

I 

* WATER RETUFfN Dl TCH 

F~~ -i 

FIGURE 34 

DRIFT CROSS-SECTIONAL GEOMETRY VIEWED IN ME INBY 

DIRECTION SHOWING VMD ANTENNA WCATIONS 

HECLA CON-S I L MINE 

TOP H(MD = I(DB) - 13.7 DB 

FIGURE 36 

MINE MAP OF HECLA MINING CO. CON-SIL MINE 

SHOWING a AND TALK TEST LOCAT IONS 
6. MF range tests were performed using the 1 Watt transmit test 

equipment and the prototype Collins mine wireless FM portable 

transceivers. 

The microwave test data was very inconclusive in this mine and was 

obtained with the transmitter located at drift center adjacent to the 

pipe shop with the receiver moving along the drift in the South 

direction. A range of only 50 feet was achieved with signal levels 

being insufficient for the corner reflector tests. 

3.3 SYSTEM PERFORMANCE CONSIDERATIONS 

Wireless transmission in a nclosedn conducting drift is possible if 

one of the drift dimensions exceeds a half wavelength (waveguide 

mode) or if the radio system antennas couple in close proximity to 

one or more conductors (monofilar mode for a single active conductor 

or common-mode-excited conductor ensemble, bifilar mode for 

differential excitation of "pairsn of conductors in the differential 

mode). Above the guide cut-off frequency transmission approaches the 

free-space propagation constrained by the guide geometry and topology 

as the refractive and scattering losses diminish and as the guide 

wavelength decreases. At low VLF and MF frequencies. the transmission 

is characterized by quasi-static coupling of the loop antennas 

(presumed small) to conductors and/or conducting surfaces in the 

geometry of the drift crossection. These low-frequency fields conform 

to the Laplace equation solution for this geometry and are excited by 

currents presumed flowing in the antennas or in the conductors by 

Ampere's law. The actual current coupling ratio between the antenna 

and these conductors is a function only of these geometric 

non-frequency-varying fields and the impedance of the antenna or 

conductors in which the nsecondaryn current is being induced (with 

performance analogous to a transformer). 

Once coupled, the signal transmission along the conductors at these low 

frequencies is governed by the physical parameters of the transverse 

electromotive mode (TEM) line, monofilar or bifilar, formed by these 

conductors. The transmission system is analogous to any TEM 

transmission line with regard to the propagation constant (attenuation 

and phase) and the superposition of traveling TEM waves. 

The transmission loss between wireless transmitting and receiving 

antennas is least at MF frequencies and the upper UHF frequencies with 

the minimum loss signal levels being nearly the same for practical 

portable systems. At intermediate HF, VHF and low-UHF frequencies, the 

transmission loss is greater because: 

- the low-frequency attenuation loss of the TEM lines 
TABLE 6 

DISTANCES TO CW LOCATI CNS ON 3000-LEVEL OF CON-SI L MINE 

100 FEET A 195 FEET 

259 8 429 

450 C 564 

630 D 1104 

783 E 1150 

963 F 1050 

1134 

1530 

2358 

1000 FT. GOWN ON 4000-LEVEL 

500 FT. UP ON 2500-LEVEL 
increases approximately linearly with frequency with 

this loss becoming very great at frequencies below the 

waveguide cut-off frequency 

- the high-frequency waveguide attenuation loss due to 

refraction and scattering is very great at frequencies 

well above the upper usable TEM frequency, this loss 

decreases rapidly with increasing frequency 

- the low-frequency coupling is reduced with increasing 

frequency into the HF band because of phase cancellation 

in the excitation region 

- the median driving point impedance levels of the TEM lines 

generally increases with frequency beyond the MF band 

which reduced the low-frequency coupling 

These intermediate frequencies are of no practical utility in 

metal/non-metal mines. The UHF frequencies are of marginal utility in 

many non-rock mines having small drift cross-sections because of 

line-of-sight limitations, with substantial attenuation encurred at 

corners, unless signals are coupled via special leaky-feeder cables. 

During the program. UHF transmission conformed to gentle bends in the 

drifts, so the transmission is not strictly limited to line-of-sight 

applications. Microwave frequency usage is strictly line-of-sight 

limited, with especially large scattering losses characterizing even 

gentle bends due to statistical roughness of the rib and back/floor 

surfaces. 

The above macroscopic effects were observed in all mines visited. 

Particularly noteworthy results of the testing include: 

- the classic waveguide cut-off frequency is of no 

practical consequence in wireless transmission at UHF 

frequencies with the transmission optimizing in the 

800 MHz region and above regardless of drift size 

- the upper practical MF frequency is about 1 MHz with 

a rapid increase in transmission losses above this 

frequency 

- the incident received field strength (or monofilar line 

current) due to excitation with a transmitting antenna 

falls off at a rate of at least 40 dB/decade for 

frequencies above approximately 1 MHz 
- a quasi-static coupling model for MF frequencies has 

been verified which accounts for conductors close to 

a conducting surface, and for the size and spacing of 

the conductors relative to the surface 

The remainder of this section will be devoted to examining the 

mechanisms which are the most probable candidates for producing these 

results. As the low frequency (MF and HF) coupling into wiring is of 

the greatest practical importance, most of the analytical effort 

involves defining the coupling phenomena. The above noteworthy results 

are apparent in the summary MF/ UHF spectral magnetic field strength 

curves (equivalent magnetic field strength for the electric data) for 

the test system shown in Figures 37 and 38. 

3.3.1 LOW-FREQUENCY COUPLING MODELS 

At VLF and low-MF frequencies, the coupling fields are largely 

quasi-static and are definable in geometrically varying terms only. 

That is, given a current flowing in an exciting source loop (transmit 

case with respect to a radio system) or in a conductor ensemble 

(receive case with respect to a radio system), the forms of the 

electromagnetic fields are independent of frequency. The induced 

current in the nreceivingw conductor ensemble or loop antenna increases 

linearly with frequency for constant exciting current and consant loop 

or line impedance. The form of the fields is controlled by the 

potential monofilar or bifilar line geometries in the drift 

cross-section as opposed to those associated with the loop antenna and 

its relative location in the drift. This effect is best visualized by 

considering the line (conductor ensemble) to be transmjtting. The 

geometric dependance of the coupled current for the transmitting loop 

antenna can then be shown to be the same by reciprocity. 

In free space. the magnetic field strength extending radially away 

from a line source carrying current is, by Ampere's law: 

L line 

H = 

2vr 

r is the range to the antenna center 

in meters 

with the open circuit voltage in a receiving loop being: 

"plline (NA) 

N, A are the number of turns and Imp 

area respect1 vel y. 
FREQUENCY - HZ 
FIGURE 38 

SUMMARY OF WIRELESS TRANSMISSION MAGNETIC FIELD 

STRENGTH CHARACTERISICS OBTAINED IN MINES #4. 

I 10 

FREQUENCY - WZ 
For a tuned matched loop, the current transfer ratio is then: 

- 

'line 2 RTTF-FT 

R is the series loop circuit 

resistance. 

For a flat matched line with a surge impedance 2 with a transmitting 

loop. the current transfer ratio by reciprocity is? 

This simple rather idealized quasi-static model is also a practical one 

for it is also appropriate for a drift of circular crossection with a 

conductor ensemble at the drift center (coaxial line). and also for 

antenna locations near the center of a wide-spaced bifilar line formed. 

by a conductor near the back and a track or ground conductor near the 

floor. These models are illustrated in Figure 39. Note for this case 

that the radial distance wfall-offw law is l/r as oppo ed to the free J space induction field fall-off away from a loop of l/r . Generally, the conductor ensemble is eccentrically located in the 

cross-section of a non-circular drift; often with the conductors in 

close proximity to one of the conducting walls. In this limit, the 

magnetic field strength away from an assumed transmitting line source 

is given by: 

where r.d.R are as defined in Figure 40. 

Corresponding expressions for current coupling ratios are readily 

obtained by replacing "r" in the previous derivations with the 
FIGURE 39 

GEOMETRIES OF CASES FOR 1/R MAGNETIC FIELD FALL-OFF 

ISOLATED LlNE SOURCE IN FREE SPACE 

CONDUCTING OUTER WALL 

LINE SOURCE 

1-/ 

CONSTRAINED COAXIAL LlNE GEOMETRY 

I 

OUT-OF-WAS 

LlNE SOURCE 

\ 

CENTER OF BIFILAR-LINE 
FIGURE 40 

M)NOFI LAR TRACK COUPL l NG MODEL GEOMTRY 

r 

I 

M)NOFI LAR R 

CONDUCTOR 

FOR CAR-CLEANER TRACK DRIFT RECEPTION: 

FOR VMJ I-FOOT = 0.3 M SPACING 

H (DB) = I (DB) - 17.0 

Y 

4-FOOT 1.22 M SPACING 

H (00) = I (DB) - 32.5 

v 

8-FOOT = 2.44 M SPACING 

H (DB) = I COB)-.- 43.8 

Y 

FOR HMD 1.1 M SPACING 
geometric quantity in brackets. Note that the field strength diminishes 

for both large and small conductors at the same center spacing from the 

surface; a phenomenon always observed in drifts containing water, sand 

and air lines. This above model was validated in the Magma Copper San 

Manuel mine test data shown in Figure 41. Monofilar line (track) 

current is plotted for various test ranges away from the line and 

compared with computed results. 

3.3.2 INTERMEDIATE FREQUENCY COUPLING & ATTENUATION 

The quasi-static coupling of a loop antenna to a monofilar conductor 

clearly occurs over a range of distances along the conductor, as the, 

range dependence for the coaxial line bound is l/r instead of l/r 

when the loop is transmitting. This oupling may be visualized as the 

integral along the conductor of l/r9 range dependencies to discrete 

current elements. The geometry for this is illustrated in Figure 42. 

As the frequency increases the phase difference between the symmetric 

coupling nzonesn as measured along the monofilar line (phase velocity 

of a traveling wave along the line) increases. Assuming that each zone 

individually couples to the line at a discrete ncentroidn location, 

the two traveling waves have a cosine relationship. As the phase 

difference between centroid locations approach9s 180 degrees, the 

coupling decreases approximately as l/f (l/f for a point field 

impinging on a receive antenna due to inductively coupled transmit 

excitation via the line). As the frequency is further increased, 

additional halfwave segments of line fall within the coupling range 

nwindown within each zone. As these segments occupy less than the 

total length of the zone, the periodic coupling amplitude recovery for 

even numbers of segments never reaches the low frequency limit with 

the zonal coupling approaching a finite bound similar to a Fresnel 

zone diffraction effect. As a result, the approximate l/f coupling 

fall-off occurs over a relatively wide frequency range. This coupling 

mechanism was verified by data taken in the AMAX mine which is given 

in Figure 43. This effect begins at a lower frequency for greater 

distances between antennas and the conductors; so, for mines with 

larger drift cross-sections, the fall-off appears to be more severe. 

The coupling is also a function of the loop and line matched 

impedances. For inductive coupling appropriate for MF and low-HF 

frequencies, optimum performance is obtained with the minimum 

impedance. The driving point impedance is a function of the surge 

impedance Zo, the line termination conditions, and line losses. At 

intermediate frequencies and above, the driving point impedance may be 

considered to be essentially equal to the surge impedance of the line. 

At lower frequencies, the driving point impedance will vary greatly 

with termination conditions. In mines, the terminations are usually 

low impedances, so that generally the driving point impedance levels 

- 

\ CEN@ID\ / CENTROID / 

\ ', / 

MAGNETIC3FIEUI LINES 

W l TH 1 /R DEPENDANC I ES 

FIGURE 42 

GEOMTRY FOR INTEFIMEDIATE FREQUENCY COUPLING 

will increase with frequency. 

Originally, the coupling decrease in the HF band was thought to be due 

to the retarded frequency-variable field term which, in a constrained 

environment, becomes the waveguide mode excitation means. This 

"radiation" term with frequency-variable current moment represents 

stored evanescent energy below the waveguide cut-off frequency. While 

this mechanism occurs, it is a relatively narrowband effect, thus 

having minimal spectral impact in the highly attenuated HF region. 

This effect will not be specifically addressed further in this report. 

The low-intermediate frequency coupling mechanisms to mine wiring show 

medium frequencies in the 200- 1000 KHz range to be optimum for 

wireless transmission. A summary of these computed coupling effects on 

transmission for the test system is illustrated in Figure 44. 

Additionally, even over particular short test ranges used for 

swept-frequency measurements, the monofilar line attenurtion increases 

approximately linearly with frequency and predominates in the overall 

transmission loss toward the high end of the HF band and above. For 

the test system operating in the 1-10 MHz spectrum over a typical test 

range of about 300-400 feet. the average attenuation rate is about 

l/f. For practical operating ranges, the attenuation in the HI band 

becomes prohibitive. The average attenuation in drifts appears to be 

about 6 dB/1000 feet at 1 MHz varying linearly with frequency. 

3.3.3 WAVEGUIDE TRANSMISSION 

UHF transmission in coal mine tunnels has been carefully analyzed by 

Arthur D. Little. Inc. under Task Order It. Task F on U.S.B.M. Contract 

H 346045. The transmission loss due to refraction and roughness have a 9 f frequency dependence which is in good agreement with measured 

data. The ADL data shows that for narrow drift widths (8-12 feet) 

these losses are substantial up to a frequency of about 1000MHz, which 

is in good agreement with the 800 MHz assessment determined during 

this program. The lower frequency losses (450 MHz or below) were also 

substantiated for low drifts. The data obtained during this program 

showed that regardless of cross-sectional drift size, there was a 

substantial signal enhancement in the high 800-1000 MHz range. For 

mines with larger drifts the fully developed waveguide mode was not 

reached until 10-20 times cut-off. The concept of cut-off frequency. 

thus, has little meaning when the refractive and roughness losses 

govern over wcopperw losses. 
0 LA Z 

z a W- - PILL > 

-I PI tn 0 Z 

m o 
4.0 INDIVIDUAL MINE REDUCED TEST DATA 

This section presents the reduced test data from the individual mines. 

This test data, both in graphic and tabular form, is representative 

data and does not necessarily include reductions of all test data 

gathered in each mine. Original test data is presented in the 

next section. 

4.1 REDUCED DATA FROM OCCIDENTAL LOGAN WASH MINE 

Swept-frequency data is given in Figure 45 (MF). Figure 46 (HF). 

Figure 47 (VHF) and Figure 48 (UHF) for two test locations. 

Figure 49 shows VHF/UHF CW test data at several frequencies taken along 

an approximate 1000-foot segment of drift including a corner; this data 

is also given in Table 7. 

Figure 50 shows CW MF test data loop-excited at 650 KHz for several 

test conditions within the drift cross-section over an approximate 

600-foottest range; this data is also listed in Table 8. Figure 51 

gives additional CW MF test data current-probe-coupled into a pager 

phone line at 650 KHz as measured over a test range of 1600 feet. 

Figure 52 gives reduced 10 CHz CW test data taken over a test range of 

approximately 160 feet; this data is also listed in Table 9. 

4.2 REDUCED DATA FROH UNITED NUCLEAR/HOMESTAKE PARTNERS SECTION 23 MINE 

Swept-frequency data is given in Figures 53 and 54 and Tables 10 and 

11 respectively for the Wagner and 650 track test areas for MF; Figure 

55 and Table 12 for HF in the Wagner area; Figures 56 and 57 and 

Tables 13 and 14 respectively for the Wagner and 650 track test areas 

at VHF; Figures 58 and 59 plus Tables 15 and 16 respectively for the 

Wagner and 650 track areas at UHF. 

MF CW test data at 650 KHz curent-probe-coupled into the phone line for 

480 VAC line cross-coupling in the Wagner drift area on a 812-foot 

range are given in Table 17. Mine-wide MF CW test data at 650 KHz over 

a 3360-foot range current-probe-coupled into the phone line are given 

in Table 18. 

VHF/UHF CW test data taken in the Wagner drift area at several 

frequencies over a 512-foot test range are given in Table 19. 

Microwave 10 GHz CW test data taken over a 97-foot range are given in 

Table 20. 

Processed MF swept-frequency data for flat -2 dB NIA over a 180-foot 
FIGURE 45 

OCCIDENTAL OIL SHALE LOGAN WASH. MINE 

RETORT #6 AREA - NEDlUM FREQUENCY SWEPT 

FIELD STRENGTH MEASUREENTS AT TWO FIXED 

RANGES - I, WA?~ HOWER INTO PRACTICAL 

WN-PACK LOOP ANTENNA CHARACTERIZATION 

CONDUCTOR-FREE 

400 600 

FREQUENCY (KHz) 
FIGURE 46 

OCCIDENTAL OIL SHALE LOGAN WASH MINE 

RETORT Y6 AFEA - HIM FREQUENCY SWEPT 

Fl ELD STRENGTH CEASUREMNTS AT I20 FEET 

RANGE - I WA~ POWER INTO PRACTICAL 

MAtJ-PACK LOOP ANTENNA CHARACTERIZATION 

CONDUCTOR- FREE 

i- I CIII(F 48 

OCCl DENTAL 01 L SIIALE LOC,A:I WASII lllNE 

RETORT /I6 AREA - UIiF S\.IEPT FIELD STRENCTbI 

IKASUREIIEHTS AT 240 FEET RAIJGE - 1 WATT 

I'OIIEl< I EJTO PI?ACT I CAL ! IAII-C'ACK ill-I I P AI4TEPINA 

250 500 750 

FREQUENCY - IWZ 

TABLE 7 

VHF/UHF CW FIELD STRENGTH EASUREMENT DATA 

LOGAN WASH MINE 

FREQUENCY (READINGS IN dB) 

LOCAT l CEI - 80M - 150FHZ 

94 

90 

9 1 

89 

ao 

80 

84 

46 

45.5 

39 

43.5 

43 

43 

33 

NOISE 

TABLE 8 

LOOP EXCITED M)NOFI LAR lvlODE 650KU Fl ELD 

STRENGTH MEASUREMENT DATA - LOGAN WASH MINE 

ANTENNA PO5 ITION 

(READINGS IN dB) 

LOCAT I ON MPT ICAL/MID-DRI FT MAX I KIM s I GNAL/'V( a-DRI FT NEAR CONDUCTORS 
FIGURE 51 

CURRENT PROBE COUPLED MF MONOFl LAR M)DE 

PROPAGATION MEASUREMENT USIHG A PAGER PHONE 

RANGE - FEET 

LOCAT I ON 

TABLE 9 

MICROWAVE FIELD STRENGTH MEASUREMENT 

DATA - LOGAN NASH MINE 
FIGURE 53 

COWARISON OF COWUTED AND MEASURED MEDIUMFREQUENCY SWEPT-FREQUENCY DATA TAKEN IN THE 

WAGNER AREA OF SECTION 23 MINE FOR BOTH 

CURRENT PF43BE AND WIRELESS EXCITED MODES OF 

TRANSMISSION VIA COWLING INTO 480 VAC LINE 

FOR 1 WATT TRANSMIT POWER AT 180 FOOT RANGE 

400 600 

FREOUENCY - KHz 
hon 

FREOIIENCY - KHz 
REDUCED SWEPT-FREOUENCY MF DATA TAKEN IN WAGNER AREA 

UNITED NUCLEAR SECT ION 23 'dl YE 

I \JATT TRANSMIT POWER AT 180 FOOT RANGE 

TX CURRENT PROBE TX ANTENNA 

MAG FIELD STRENGTH MAG FIELD STRENGTH 

FREO(WZ) DB ABOVE I uA/M DB ABOVE I uA/M 

TABLE I I 

REOlJCED SWEPT-FREQUENCY MF DATA TAKEN IN 650 TRACK AREA 

UNITED NUCLEAR SECTION 23 MINE 

I WATT TRANSMIT POWER AT 180 FOOT RANGE 

FREQ ( WZ ) 

TX CURRENT PROBE TX ANTENNA 

rrAG FIELD STRENGTH MAG FIELD STRENGTH 

DB ABOVE I uA/M DB ABOVE I uA/M 

TABLE 12 

REDUCED SWEPT-FREOUEFICY HF DATA TAKEN 1El WAGNER AREA 

UNITED IllKLEAR SECTIOX 23 MINE 

I WATT TRANSM l T POWER AT 1 80 FOOT RANGE 

TX CURRENT PROBE TX ANTENNA 

MAG FIELD STRENGTH M4G FIELD STRENGTH 

FREO ( WZ) DB ABOVE I uA/M DB ABOVE I uA/M 
FIGURE 56 

VHF SWEPT-FREQLENCY DATA TAKEN 

OF lJNlTED NUCLEAR SECTION 23 M

POLARIZATION ORIENTATIONS OF B

ANTENNAS - NOlU-iALIZED FOR I-WAT

PRACTICAL MAN-PACK WHIP ANTENNA 
FIGURE 57 

VHF SWEPT-FREQUENCY DATA TAKEN IN 650 TRACK 

AREA OF UNITED NUCLEAR SECTION 23 MINE FOR 

SEVERAL POLARIZATION ORIENTATIONS OF 

BlCONlCAL TEST ANTENNAS - NORMALIZED FOR 

I-WATT INTO PRACTICAL MAN-PACK WHIP ANTENNA 

CHARACTERIZATION AT 180 FOOT RANGE 

100 

FREQUENCY - FWZ 
REDUCED SWEPT-FREOUENCY VHF DATA TAKEN IN WAGNER AREA 

OF lJNlTED NUCLEAR SECTION 23 VINE 

I-WATT TRAVSMIT POWER AT 180 FOOT PAN'3-E 

H-W L BROADS I DE V-WL H-POL COLLINEAR 

DB ABOVE 1 uV/M C8 ABOVE I uV/M DB ABOVE I uV/M 
TABLE 14 

REDUCED SWEPT-FREOUEYCY VHF DATA TAKEN IY 650 TQACK AREA 

OF UNITED F.IUCLEAR SECTION 23 MI YE 

I WATT TRANSMIT WWER 4T 1 80 FOOT PAIIGE 

FREO ( WZ 

H-POL BROADSIDE 

DB ABOVE I uV/M 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

44.4 

48.8 

- 

v-POL 

DB ABOVE I uV/M 
< 

Z a5 z 

a ,wag 

$FEU 

=Lon 

owZ N -m-3 

z 2 

ZZPt: 

XI-=< <<on 

I-NZ I 

z 2pg 

<Am # 0 0 < --I 

nz< 

Z 0 z ggr- = wnzt 

3.G a s k'_Zga 

UCCWO 

tat+ 

!i Z = 0 - 

W)-=t ZBgG 

LLCCCLZ 

OW l 3ua- 
no0 600 

FREQIIENCY - !HZ 
TABLE 15 

REDUCED SWEPT-FRE13UEFICY UHF DATA TAKEN 1b1 WAG'IER AREA 

UYITED NUCLEAR SECTIOY 23 MlNE 

I WATT TRANSMIT POWER AT 180 F30T RANGE 

H-POL BROADS1 M V-POL 

FREO ( HZ) DB ABOVE I uV/M DB ABOVE I uV/M 

TABLE 16 

REDUCED SWEPT-FREQUENCY UHF DATA TAKEN IN 650 TRACK AREA 

UNITED NUCLEAR SECTION 23 MINE 

I WATTTRANSMIT POWER AT 180 FOOT RANGE 

+POL BROADSIDE V-POL 

FEO(MHZ) DB ABOVE I uV/M DB ABOVE I uV/M 
CW MEDIUM FREQUENCY DATA IN WAG'IER DRIFT AREA 

AT 650 KHz 

( Readings taken in the center of the drift ) 

MAGNET I C FIELD STRENGTH RAW SINGER 0 l STANCE 

LOCAT I ON DB ABOVE I UAMP/METER NM-25 DATA FROM TX n 

0 

I 

2 

heater feed 

4 

5 

heater feed 

I heater feed 

8 

+24 on +40 

+20 on +40 

+12fon +40 

+I2 on +40 

+I3 en +20 

+l2fon +20 

+I0 on +20 

+I 1 on 0 

lost signal 

14 

114 

206 

302 

394 corner 

512 

626 

716 

812 

NOTES : 1. TRANSMITTER CONNECTED TO PHONE LINE VIA STODOARO 

CURRENT PROBE AT PRINCIPAL WAGNER AREA TX LOCATION 

2. DATA NOFMALIZED TO I-WATT OF TX POWER ( NI A = 0.89 ) 
TABLE 18 

CW MEDIUM FREOUENCY OATA OVER LPRGE 'JIME AREA FRON 

TX LOCATED IN PRINCIPAL WAGNER AREA LOCATION OF 

UNITED NUCLEAR SECTION 23 MINE WITH COUPLING TO 

PHONE LINE VIA STODDARD CURRENT PROBE 

AT 650 KHz 

( Readings taken in drift center unless otherwise noted 1 

MAGNETIC FIELD STRENGTH RAW SINGER DISTANCE 

LOCAT I ON NOTES DB ABOVE I uAW/METER N&25 DATA FROM TX FT 

WAGNER SHOP 

NEAR PHONE 

MIN LEVEL 

MAX LEVEL 

650 LEVEL PORTAL SHAFT 

726 LEVEL PORTAL SHAFT 

58 EAST TRACK BRANCH 

MAIN 726 LEVEL TRACK 

DR l FT CENTER 

ANT ON RA I LS 

NOTE: RECEIVE SENSITIVITY LEVEL APPROX. -34 DB ABOVE I uAW/METER 

FOR 12 DB SIG1AL,THEREFORE AMPLE SIGNAL IS AVAILABLE AT ALL 

TEST POINTS FOR COWN I CAT IONS DATA NORMAL1 ZED TO 1 WATT 

TRANSMIT POWER 
LOCAT I ON 

0 

I 

2 

3 

4 

5 

NOTE : 

?+I VHF nATA TAKE'! Ikl WPC?!ED C?! FT ADEP 

ljrl I TED ~JOCLEAR SECT I O?I 23 h.4 I wE 

( geeadings taken in the center of the drift 

VERTICAL POLARIZATION 

ELECTRIC FIELD STRENGTH IN DB ABOVE I uV/M 

50 WZ 100 Mi2 200 FHZ 01 STANCE( FT) 

105.7 112.8 111.7 14 

52.7 75.8 71.7 114 

lost 35.8 34.7 206 

lost lost lost 362 

HORIZONTAL POLARIZATION 

ELECTRIC FIELD STRENGTH IN DB ABOVE I uV/M 

so mz 100 mz 200 mz DISTANCE(FT) 

78.7 123.8 119.7 14 

lost 84.8 97.7 114 

lost 39.8 65.7 206 

lost 41.8 69.7 302 

lost 45.8 45.7 394 CORNER 

lost lost lost 5 12 

DATA WRMALIZED TO I-WATT OF TX POWER INTO PRACTICAL 

WN-PACK ANTENNA 
TABLE 20 

X-BAND MICROWAVE TEST DATA TAKEN IN WAGNER AREA 

llFJlTED tlUCLEAR SECTION 23 MI'IE I WATT TRANSMIT POWED 

(A) RANGE TEST - 

NM-65T READINGS F I ELD STRENGTH 

DB ABOVE I uV DB ABOVE I uV/M RANGE(FT) 

NOTE: Noise level at 29 DBuV on Nk65T 

(B) DEPOLARIZATION TEST - 

TX SET-UP AT WAGNER AREA TRANSMIT SITE 

RX FIELD STRENGTH INCIDENT ON REFLECTOR: 

66.9 uV/M NOMINAL 

3 06 VARIATION IN VERTICAL PLANE 

6 DB VARIATION IN HORIZONTAL PLANE 

TRANSVERSE TO DIECTICN OF PROPAGATION 

RX REFLECTED Fl ELD STRENGTH 8 18 FEET RANGE FROM REFLECTOR: 

66.4 DB RELATIVELY INDEPENMNT OF SPECIFIC 

LONGITUDINAL DIRECTION LOCATION OF 

RX HORN 
range in the Wagner area are shown in Figure 60. Attenuation is 

assuned negllglble over thls range due to mesh on the back and ribs. 

A summary of conductor ensemble impedances deduced from MF measurements 

is given in Table 21. 

4.3 REDUCED DATA FROM KERR-MCGEE HOBBS POTASH FACILITY MINE 

Swept-frequency data is given in Figure 61 for MF at two test ranges, 

Figure 62 for HF at a 300-foot range, Figure 63 for VHF at two test 

ranges and Figures 64 at a test range of 150. Additionally. MF current 

probe excited measurement at a range of 300 feet is given in Figure 

65. 

MF CW test data at several frequencies antenna-coupled over a nominal 

750-foot test range is given in Figure 66 and in Table 22. More 

detailed MF Cbl test data at 650 KHz over an approximate 9500-foot test 

range is given in Figure 67 and in Table 23. 

UHF CW data @ 600 and 950 MHz over an approximate 1600-foot test range 

is given in Figure 68 and in Table 24. 10 GHz CW test data over a 

195-foot test range is given in Table 25. Processed MF swept-frequency 

data for flat -2 dB NIA taken over a 150-foot test range is given in 

Figure 69 with and without attenuation. 

4.4 REDUCED DATA FROM THE AMAX LEAD CO. OF MISSOURI BUICK MINE 

A composite of MF swept-frequency data taken vs range out to 

approximately 6800 feet in the haulage area beyond the Y is given in 

Figures 70 and 71 and in Table 26. Similar CW test data over the same 

range at 520 KHz for antenna loop coupling into phone line and 

dedicated wire is given in Figure 72 and in Table 27. 

MF and HF swept-frequency data over a 390-foot test range is given in 

Figure 73 and respectively in Tables 28 and 29. Similar 

swept-frequency test data over a 1290-foot test range having the same 

transmitter location is given in Figure 74 and respectively in Tables 

30 and 31. VHF and UHF swept-frequency data over a 390-foot test range 

is given in Figure 75 and respectively in Tables 32 and 33. 

Processed MF swept-frequency data for flat -2 dB NIA taken over a 

390-foot test range is given in Figure 76 with and without attenuation. 

4.5 REDUCED DATA FROM MAGMA COPPER CO. SAN MANUEL MINE 

MF and HF swept-frequency data characterizing monofilar mode coupling 

into a track over a 243-foot test range is given in Figure 77 and in 

Tables 34 and 35. Companion data illustrating monofilar track current 
FIGURE 60 

PROCESSED MF AND HF DATA FW WAGNER AREA OF UNITED NUCLEAR 

SECTION 23 MINE AT 180 FOOT TEST RANGE FOR FLAT NIA OF -2 D

I 10 

FREQUENCY - MHZ 
FREQ ( M-IZ 

0.20 

0.25 

0.35 

0.45 

0.55 

0.65 

0.75 

0.85 

0.95 

TABLE 21 

SIMMARY OF CONDtCTOR ENSEWLE IWEDANCES DEDUCED FROM MASUREMNTS 

(MITED NIKLEAR SECTION 23 MINE 

WAC34ER AREA WAaJER AREA 650 TRACK AREA 

TX PWBE TX ANTENNA TX PROBE 

480 VM: LINE 480 VAC LINE/WATER LINE PHONE LINE 
+++*tss i WWWWWWWttjOrL 

I LLLLLL WJ 
K FIGURE 62 

5 KERR-MCGEE HOBBS POTASH FACl Ll

& 

-. 

AREA 140-BTX3 HIW FREQUENCY 

< STRENmH MEASURENNTS AT 300 F

3 

- 1 WATT POWER INTO PRACTICAL MA

ANTENNA CHARACTERIZATION WITH 

5 20 

I 

PRESENT 

k 

K 

W 

Iu 

g lo 

LC 

D 

I 

E O 

z 

W 

K 

Iul 

a 

d -10 - 

LL 

U 

- 

3 -20 

? 4 6 A I r) I? 14 16 

FREQIENCY - WZ 
FIGURE 63 

KERR-W,r&E HOBBS POTASH FACl LlTY MINE 

AREA 140 - BTY3 VHF SWEPT FIELD STRENGTH 

MASllREMNTS AT TWO Fl XED RANGES 1 WATT 

ANTENNA ORIEN

HORIZONTAL PO

VERTICAL POLA

u rnAxl AI 

- - . . . , . . . - 

TRANSMIT POWER INTO PRACTICAL MAN-PACK 

WHIP ANTENNA CHARACTERIZATION WITH 

ORTHOGONAL (V

a. 

w c CONDUCTORS PRESENT 

I! 0- 0 HORIZONTAL PO

lIlil!Ii m-q VERTICALPOLAR

FREDIICFICY - KHZ 
FIGURE 

KERR-MCGEE HOBBS POTAS

AREA t40 - BT13 MDllM 

WAVE F l ELD STRENGTH MA

1 WATT WWER INTO PRAC

ANTENNAS WITH CONDUCTO

650MZ AND 

M 250KHZ COPLANAR HM) 

&----A 650KHZ OORLANAR HM) 

950MZ COPLANAR HM) 

@- - -0 250KHZ COPLANAR VMD 

-A 650KHZ COPLANAR VMD 

- 950KHZ COPLANAR VMD 

0 100 ZOO 300 400 500 600 700 

RANGE (FEET) 
TABLE 22 

MEDIUM FREQUENCY CONTINUOUS WAVE FIELD STRENGTH MEASUREMENT 

DATA KERR-=GEE HWBS POTASH FACl LlN MINE AREA 140-01 #3 

1 WAlT TRANSMIT POWER 

COPLANAR HMO MEASUAEMENTS (IN dB GREATER THAN 1 uV) 

LOCATION 1Y DISTANCE (FEET) 250 KHz - 650 KHz 

1 150 32 66 

2 210 36 70 

COPLANAR VM) MEASVREMENTS (IN dB GREATER THAN 1 uV) 

LOCATION X DISTANCE (FEET) 250 KHZ 650 KHz 

1 150 15 44 

2 2 10 12 40 

3 370 14 48 

4 570 -7 12 

5 7 30 -4 -1 1 
0 0 

0 m 

0 0 V) v 0 

N 

0 0 

- N 

1 

tl3UW/dWVOtl31W L NVHl 831V33 BP - HBN3tllS 01313 31UL9VW 
TABLE 23 

EONDUCTOR-ENHANCED MEDIUM FREOUEYCY QNTINUOUS 

WAVE FIELD STRENGTH MEASUREMENTS - KERR MCGEE 

HOBBS POTASH FACILITY 650 KHZ TEST FREQUENCY 

I WAlT TRANSMIT POWER 

FEET Dl STANCE FROM 

LOCATION # CONDUCTORS-METERS READING (dB ABOVE 1 uV) 

1 10 0.6 92 

2 250 0.6 50 

3 550 0.6 5 1 

4 820 0.6 5 1 

5 1370 0.6 43 

6 1850 0.6 4 3 

7 2420 0.6 38 

8 2980 0.6 34 

9 3450 0.6 34 

10 4030 0.6 2 8 

11 4580 0.6 36 

12 5260 0.6 25 

13 5760 0.6 27 

14 6 160 UNKNOWN -5 

SEE FIGURE 27 FOR TEST LOCATlCNS 

TABLE 24 

UHF CONTINUOUS WAVE FIELD STRENGTH MEASUREMENT DATA 

KERR-MCGEE WRBS POTASH FACI LITY MINE ROOM 225 

(HORIZONTAL ANTENNA POLARIZATION) 

1 WATT TRANSMIT POWER 

(IN dB ABOVE I uV) 

LOCAT ION # DISTANCE (FEET) 600 MHz 950 M-IZ 

1 20 64 60 

TABLE 25 

MICRJWAVE FREQUENCY CONTINUOUS WAVE FIELD STRENGTH 

MEASUREMENT DATA KERR-MCGEE HOBBS POTASH FACI LlTY 

27 WEST ( 1 WAlT TRANSM l T POWER- 10 WZ ) 

LOCAT I ON X DESCRI FTlON DISTANCE (FEET) READING (dB) 

I BT 12 East Edge 2 34/40 scale 

2 BT 12 West Edge M 42/ 0 scale 

3 BT 13 West Ed- 105 

4 BT 14 west Edge 180 

39/ O scale 

37.5/ 0 scale 

5 9T 14 15' South of 195 39.51 0 scale 

Ref lector 
FIGURE 69 

PROCESSED MF AND HF DATA FROM KERR-FICGEE POTASH MINE ON 150-FOOT 

TEST RANGE FOR FLAT NlA OF -2 WITH AND WITHOW ATTENUATION 

I 10 

FREQUENCY - MHZ 
RANI* - KILOFEET 

TABLE 26 

REDUCED MARlETlC FIELD STRENGTH DATA TAKEN ON A SWEPT-FREQUENCY 

BASIS WITH RANX ALONG THE NORTH MINE TRACKED HAULAGE DRl FT AWAY 

FROM A I-WATf TRANSMITTER LWP-COUPLED INTO THE DEDICATED WIRE 

IN THE FOREMAN'S SHACK AMAX LEAD CO. BUICK MINE 

STATION 005 SCOPE STATICN 020 SCOPE 

FREQUENCY(MH2) H OB ABOVE I uA/M DBM H DB ABOVE I uA/M DBM 

STAT ION 034 SCOPE 

H DB ABOVE I uA/M OEM 

STATION 049 

H 08 ABOVE I 

SCOPE 

uA/M OBM 
TABLE 26 CONT. 

FREQUENCY ( tWZ 

STAT1 ON 064 

H OB ABOVE I uA/M 

STATION 086 

H 00 ABOVE I uA/M 

SCOPE 

OBM 

SCOPE 

0BM 

STATION @ Y 

H OB ABOVE I 

STATION 113 

H DB ABOVE I 

SCOPE 

uA/M OEM 

SCOPE 

uA/M DBM 

TABLE 27 

RESULTS OF VF CI.1 DEMONSTRATION TESTING AT 520 KHz USING 

COLLINS PROTOTYPE BASE STATION AS THE TRANSMITTER IN THE 

FORMAN'S SHACK AND USING A S INrZ4 Fl ELD STRENGTH METER 

PLUS A PORTABLE COLLINS UNIT ALONG THE NORTH MlNE TRACKED 

HAlJLAGE DRI FT AMAX LEAD CO. BUlCK MlNE 

LOOP-COUPLED TO DEDICATED WIRE LOOP-COUPLED TO PHONE LINE 

LOCATION SINGER READINGS H DB ABOVE I uA/M SINGER READINGS H OB ABOVE l uA/ 

+ 8 on +60 

+ 8 on +40 

+ l on +40 

+I 7i.m +20 

+ 8fon +20 

+ 1 4ton +20 

+17on 0 

+I4 on -20 

+ 2 on -20 

barely hear xmtr 

!KITE: STATION 113 WAS FARTHEST AWAY THAT TWO-WAY COMMUNICATIONS 

COULD BE MAINTAINED ( 15 WATT BASE 6 15 WATT PORTABLE ) 

8 STATION 129, PORTABLE-BASE LINKAGE WAS LOST BUT BASEPORTABLE L INKAGE WAS ST1 LL COPYABLE. 

TABLE 28 

REDUCED MAGVETIC FIELD STRENGTH AND COUPLED CURRENTMF DATA 

TAKEN ON A SWEPT-FREOUENCY BASIS AT 064 ORE PASS FROM A 1 WATT 

TRANSMITER LOCATED AT THE NORTHWEST/NORTHEAST Y AMAX LEAD CO. 

- BUICK fH YE - 

TX PROBE-RX PROBE TX PROBE-RX ANTENNA 

mEOVENCY(MiZ) DBM 1 IN DB ABOVE i uA DBM H(DB ABOVE IuA/M) I(DB ABOVE I 

TX ANTENNA-RX ANTENNA 

FREOMNCY(MiZ) DBM H(DB ABOVE I uA/M) I(DB ABOVE l uA) 

CllRRENT CALCULATED ASSUMl NG f-MmR RAD 1 US mOM CON WCTORS 
TABLE 29 

REDLCED !."AWETIC FIELD STRENGTH AND COUPLED CURRENTMF DATA 

TAKEN ON A SWEPT-FREQUENCY BASIS AT 064 ORE PASS mOM A 1 WATT 

TRANSMITER LOCATED AT THE NORTHWEST/FIORTHEAST Y AMAX LEAD CO. 

BUICK M IN€ 

TX PROBE-RX PROBE TX PROBE-RX ANTENNA 

FREQUENCY(W2) DEM I IN DB ABOVE L uA OEM H(DB ABOVE luA/M) t(DB ABOVE 1 

TX ANTENNA-RX ANTENNA 

FREOIIENCY(M-lZ) DBM H(DB ABOVE IuA/M) I(DB ABOVE luA) 

CURRENT CALCULATED ASSUMING I-MTER RADIUS FROM CONWCTORS 
tiZ I I 

4 2 I I I I 

ZW I 

WZC I 1 I I 

EY5 I I z 2 

- 

LUX 

X X 

a 

a a; - -2 

WWZ 

m8k E E z 

XXX 

CCI- 
TABLE 30 

REDUCED MABlETlC FIELD STRENGTH AND COUPLED CURRENT MF DATA 

TAKEN ON A SWEPT-FREOUENCY BASIS AT 049 ORE PASS FROM A 1 WATT 

TRANSMITTER LOCATED AT THE NORlHWEST/NORTHEAST Y 

AMAX LEAD Kl. - BUlCK MINE 

TX PROBE-RX PROBE TX PROBE-RX ANTENNA 

FREQUENCY(!MZ) OBM I IN DB ABOVE i uA DBH H(DB ABOVE iuA/M) I(DB ABOVE 1 

TX ANTENNA-RX ANTENNA 

FREOl!ENCY(MiZ) DBM H(DB ABOVE luA/M) I(DB ABOVE luA) 

CURRENT CALCULATED ASSUMING I-MTER RADIUS FROM CONDUCTORS 
TABLE 31 

REDUCED MAGNETIC FIELD STRENGTH AND COUPLED CURRENT HF DATA 

TAKEN ON A SWEPT-FREOUENCY BASIS AT 049 ORE PASS FROM A 1 WATT 

TRANSMllTER LOCATED AT THE NORTHWEST/NORTHEAST Y 

AM9X LEAD CO. - BUlCK MINE 

TX PROBE-RX PROBE TX PROBE-RX ANTENNA 

FREOUENCY(WZ) DBM 1 IN DA ABOVE 1 uA DBM H(DB ABOVE 1uA/M) I(DB ABOVE 1 

TX ANTENNA-RX ANTENNA 

FRE'YUENCY(Mi2) DBM H(DB ABOVE luA/V) I(DB ABOVE luA) 

CURRENT CALCULATED ASSUMING {-METER RADIUS FROM CONDUCTORS 

TABLE 32 

RE~IJCED VHF ELECTRIC FIELD STREFIKI'H DATA TAKEN ON A SWEPTmEOUEUCY BASIS ALONG ME NORTH MlNE TRACKED HAULAGE OR1 FT 

AT 064 ORE PASS FROM A TRANSMITTER LOCATED AT THE NORTHWEST/ 

VORTHEAST Y 1 WATT TRANSMIT POWER FOR PRACTICAL WHIP ANTENNAS 

AMAX LEAD CO. - BUlCK MINE 

HORIZONTAL WLARIZATION VERTICAL POLARIZATION 

FREO(MHZ) DBM E(DBAB0VE IuV/M) DRM E(DR ABOVE IuV/M) 
FREO (MHZ) 

REDUCED UHF ELECTRIC Fl ELD STRENGTH DATA TAKEN ON A SWEPTFREnllENCY BASIS ALONG THE NORTH MlNE TRACKED HAULAGE DRIFT 

AT 064 ORE PASS FROM A TRANSMITTER LOCATED AT THE NORTHWEST/ 

NORTHEAST Y 1 WATT TRANSMIT POWER FOR PRACTICAL WHIP ANTENNAS 

AMAX LEAD CO. - BUlCK MINE 

HORIZONTAL POLARIZATION VERTICAL POLARIZATION 

DRM E(DB ABOVE IuV/M) DBM E(DB ABOVE IuV/M) 


TABLE 34 

REWCED MARIETIC FIELD STRENGTH AND COUPLED CURRENT DATA 

TAKEN ON A SWEPT-FREQUENCY BASIS IN THE CAR-CLEANER TRACK 

DRIFT WHICH CONTAINED NO OTHER SI*JIFICANT CCNWCTORS AT MF 

1 WATT TRANSMIT WWER MAGMA COPPER CO. SAN MANUEL MINE 

TX 6 RX ANTS COPLANAR HMO I.IM ABOVE TRACK CENTER 

FREQuENCY(MHZ) DBM H(DB ABOVE IuA/M) I(D@ ABOVE luA) 

RX ANT VM) SPACED AS GIVEN ABOVE RAlL TOP 

4-FT 8-Fr I -Fr 4-FT 8-FT 

DBM DEW H(DB) I(W) HtDB) ItDB) H(DB) I(DB) ABOVE IuA 

- - +16.U +33.0 - - - - OR I uA/M 

-48.0 - - C21.7 +38.7 - - - - 

-42.0 -56.0 -71.0 +27.7 C44.4 +13.4 +45.9 - 1.6 +42.2 

-37.0 -51.0 -68.0 +31.5 +48.5 +17.5 +50.0 - 0.1 +43.7 

-30.0 -43.5 -58.0 +37.0 +54.0 +23.5 +56.0 + 9.0 +52.8 

-27.0 -37.0 -52.5 +38.1 +55.1 +28.5 +61.0 +12.6 +56.4 

-28.0 -39.5 -55.0 +35.3 +52.3 +24.2 +56.7 + 8.3 +52.1 

-36.0 -49.0 -62.0 +24.7 +41.7 +12.1 +44.6 - 1.3 +42.5 

-43.0 -56.0 -69.0 +16.0 +33.0 + 3.2 +37.5 -10.0 +33.8 
TABLE 35 

REDUCED MAGNETIC FIELD STRENGTH AND COUPLED CURRENT DATA 

TAKEN ON A SWEPT-FREOIJENCY BASIS If4 ME CAR-CLEANER TRACK 

DRl FT WHICH CONTAINED NO OTHER S IGNl FlCANT CONDUCTORS AT HF ' T"NsM'T ~ufi~~8pp&~L$~~~fi~~~~$f&\~ ;RACK CENTER 

FREQUENCY ( f8.2) DBM H( DB ABOVE I uA/M) I(DB ABOVE luA) 

RX ANT VM) SPACED AS GIVEN AROVE RAIL TOPS 

1-FT 4-FT 8-FT I -FT 4-FT 8-FT 

FREQ(h%Z) DBM DBM DBM H(DB) I(DB) H(DB) I(DB) .H(DB) I(DB) 

H in DB ABOVE IuA/M 

1 in DB AROVE iuA 
and details of the track geometry is given In Flgure 78. 

Swept-frequency data is shown in Figure 79 for VHF and in Figure 80 for 

UHF. 

Reduced HF CW data in the North and South mine legs of 2375-level in 

the carrier phone band at 145 KHz over an approximate 6000-foot test 

range is given in Figure 81 and in Table 36. The data was taken in a 

mobile train with the transmitter directly driving a dedicated wire 

network in the locomotive shop. Similar CW data taken at 520 KHz. but 

with the receiver in the fixed location, is shown in Figure 82 and in 

Table 37. 

Processed HF swept-frequency data for flat -2 dB NIA taken over the 

243-foot test range with attenuation for both VHD and HHD antenna 

orientations are given in Figure 83. 

4.6 REDUCED DATA FROM HECLA CON-SIL MINE 

MF and HF swept-frequency data taken on a 429-foot path for several 

antenna orientations is given in Figure 84 and in Tables 38 and 39 

respectively for HMD and VHD orientations at HF and in Tables 40 and 41 

respectively for HHD and VHD orientations at HF. Processed HF and HF 

data normalized for unity NIA is given in Figure 85. 

VHF and UHF swept-frequency data taken over a 195-foot path is given 

in Figures 86 and 87 respectivly for horizontal and vertical antenna 

polarizations and in Tables 42 and 43. 

Reduced HF CU data at several frequencies over an approximate 1500-foot 

range are given in Figures 88 and 89 respecttvely for Sunshine raise 

and Winze shaft directions and is listed in Table 44. 

Processed HF swept-frequency data for flat -2 dB NIA taken over a 

429-foot range with and without attenuation is given in Figure 90. 
COt.tPLITED MF/HF $.IONOF I LAR flOOE TRACK COUPL I HG CORRESPOFIOI PIG 

TO CAR-CLEANER DR l FT PIEASUREFIEFJTS - MAGMA COPPER CO. SAY h4ANUEL ?.I I ?JE 

COPLANAR HM) LOOP ORIENTATION 

I/ 

TEST SET INA TRACK CURREKT( 2 CONO. 1 

FREO ( wz AMP~~TURNS DB ABOVE i UAWERE 

YOTES: SURGE IMPEDA!ICE OF 100 OHMS / RAl L ASSUMED TO GROUND 

IMAI;E RETUFIN PATH IS IN GROUNO(ROCK) 

TRACK CURRENT IS TOTAL OF TWO LOOP VALUES 

EOUIVALENT H FIELD IS 29.2 OB BELOW CURRENT FOR 

SHOWN EXCITAION LOCAT IONS ( WHICH ARE 4011CH~Y 

EOUIVALEVT FOR 3OTH ORIENTATIONS ) 
FIGURE 79 

SWEPT-FREQUENCY VHF REDUCED DATA FOR PRACTICAL 

WHIP ANTENNAS TAKEN IN CAR-CLEANER TRACKED 

DRIFT AT A RANGE OF Ill FEET FROM THE 

TRANSMITTER - I WATT TRANSMIT POWER 

MAWA CCWER CD. SAN MANUEL MINE t 

FREOIENCY - WZ 

FIGURE 81 

TEST SYSTEM REMICFI) HF DATA EXPRESSED AS 

MX4OF I LAR MOM CURHENT FROM CARRIER PHONE 

TESTING ON BASE-VEHICLE AND VEHICLE-BASE 

PAWS AT 145KHz AND 52004~ RESPECTIVELY 

MAC244 COPPER CO. SAN MANUEL MINE 

(SEE MAGMA COPPER MINE MAP IN FIGURE 301 

RANGE - KILOFEET 
TABLE 36 

REWCED DATA FROM 145 KHZ CARRIER PHONE TESTS ON ME 

BASE-VEHICLE LINKAGE ALONG THE MASUREMENT TRAVERSE 

MAGMA COPPER CO. SAN MANUEL MINE 1 WATT TX POWER 

WNOF I LAR CURRENT 

LOCAT I ON OBM DB ABOVE I uAWERE 

PEWCED DATA FROM 520 KHz CARRl ER PHONE TESTS ON THE 

VEHICLE-BASE LINKAGE ALONG THE MEASUREMENT TRAVERSE 

MAGMA COPPER CO. - SAN MANUEL MINE 

WNOFI LAR CURRENT 

LOCAT I ON C%M DB ABOVE I uAMPERE 

A -39.0 +22.4 CORRECTED FOR PREA tfP 

B -39.0 +22.4 II II II 

C -47.0 +14.4 11 11 tt 

C -54.0 + 7.4 I, 11 It 

D -57.0 + 4.4 II II It 

E -53.0 + 8.4 It II I1 

F -59.0 + 2.4 11 II II 

G 69.0 - 8.) n 19 11 

H -66.0 - 4.6 ~t 11 11 

I -64.0 - 2.6 

J -73.0 -1 1.6 

K -67.0 - 5.6 

L -54.0 + 7.4 

M -35.0 +26.4 

N -60.0 + 1.4 

0 -49.0 +12.4 

P -45.0 +16.4 

0 -43.0 +18.4 

R -38.0 WRT 

-45.0 VEHlC +23.4 

S -30.0 WRT 

-28.0 VEHlC +31.4 

T -32.0 +29.4 

[I -35.0 +26.4 

V -30.0 WRT 

-43.0 VEHIC +lea4 

W -50.0 +I 1.4 

NOTE : THESE CURRENT VALUES AS RECEIVED IN THE RADIO SHOP ARE 

INCREASED BY 37.5 00 TO GIVE ACTIJAL WNOFILAR CURRENT 

ON THE TROLLEY SYSTEM 
FIGURE 83 

PROCESSED MF AND HF DATA FROM MAGMA SAN MANUEL MINE ON 243-FOOT 

TEST RANGE FOR FLAT NIA OF -2 OB FOR HM) AND VMD ANTENNA ORIENT

1 WATT TRANSMIT WWER AND TEST SYSTEM ANTENNAS 

5 

TABLE 38 

REDUCED MAGNETIC FIELD STRENGTH AND COUPLED CURRENT DATA 

TAKEN ON A SWEPT-FREQUENCY BASIS N ME 3000- LEVEL NORM 

CROSSCUT ON A 429 FOOT PAM ATH FOR VMO ANTENNA ORIENTATIONS 

1 WATT TRANSMIT POWER FOR TEST SYSTEM ANTENNAS 

HECLA CON-SIL MINE 

TOP 

DBM 

-41.0 

-32.0 

-26.5 

-23.0 

-22.0 

-16.0 

-16.0 

-23.5 

-26.5 

MID 

DBM 

-62.0 

-59.0 

-54.0 

-51.0 

-47.0 

-43.0 

-43.0 

-48.0 

-53.0 

BOT 

DBM 

61.0 

-58.5 

-63.0 

-63.0 

-54.0 

-47.5 

-47.5 

-50.5 

-55.0 

TOP 

H(DB) I(U3) 

+28.5 +42.2 

+37.7 +51.4 

+42.9 +56.6 

+45.5 +59.2 

+45.0 +58.7 

+49.1 i62.8 

+47.3 +61.0 

+37.2 +50.9 

+32.5 +46.2 

MID 

H(DB) Z(C8) 

+7.5 +40.0 

+10.7 +43.2 

+15.4 +47.9 

+17.5 +50.0 

+20.0 +52.5 

+22.1 +54.6 

+20.3 +52.8 

+12.7 +45.2 

+6.0 +38.5 

BOT 

H(DB) I(08) 

+8.5 +48.5 

+11.2 +51.2 

+6.4 +46.4 

+5.5 +45.5 

+13.0 +53.0 

+17.6 +57.6 

+15.8 +55.8 

+10.2 +50.2 

+4.0 +44.2 

H in OB ABOVE l uA/M 

L in OB mVE luA 
TABLE 39 

REDUCED MAGNETIC FIELD STRENGTH AND COUPLED CURRENT DATA 

TAKEN ON A SWEPT-FREQUENCY BAS IS IN THE XIOO-LEVEL NORM 

CROSSCUT ON A 429 FOOT PATH AT HF FOR HMD ANTENNA ORIENTATIONS 

1 WATT TRANSMIT POWER 

HECLA CON-SIL MINE 

CURRENT 

PROBE 

DBM I(DB) 

TX d RX ANTS COLLINEAR HMD 

M l DDLE BOTTOM 

DBM H(DB) I(DB) DBM H(DB) 
TABLE 40 

REDUCED MAGNETIC FIELD STRENGTH AN0 COUPLED CURRENT DATA 

TAKEN ON A SWEPT-FREQUENCY BASIS IN ME 3000-LEVEL NORTH 

CROSSCUT ON A 429 FOOT PATH AT HFFDR VMO ANTENNA ORIENTATIONS 

1 WA~ TRANSMIT POWER 

HECLA CON-S I L M ItlE 

TOP 

FREQ(MHZ) OBM 

2.0 -24.5 

4.4 -40.0 

7.9 -30.0 

1122 -31 .O 

14.4 -32.0 

18.0 -22.0 

MID 

DBM 

-47.0 

-53.0 

-55.0 

-50.0 

-52.0 

-55.0 

BOT 

DBM 

-64.0 

-74.0 

-66.0 

-63.0 

-77.0 

TOP 

H(DB) I (DB) 

+37.5 +51.2 

+12.4 +26.1 

+21.6 +35.3 

+19.7 +33.4 

+18.0 +31.7 

+27.7 +41.4 

H in DB ABOVE l uA/M 

I in DB ABOVE luA 

MID 

H(DB) I(DB) 

+15.0 +47.5 

-0.6 +31.9 

-3.4 +29.1 

+0.7 +33.2 

-2.0 +30.5 

-5.3 +27.2 
TABLE 41 

EDUCED MAGNETIC FIELD STRENGTH AND COUPLED CURRENT DATA 

TAKEN ON A SWEPT-FREQUENCY BASIS IN THE MOO-LEVEL NORTH 

CFdOSSCUT ON A 429 FOOT PATH AT HF FOR HMO ANTENNA ORIENTATIONS 

1 WATT TRANSMIT POWER 

HECLA CON-S I L MI tIE 

CURRENT 

PROBE 

FREQCWZ) OBM I (DB) 

2.0 +4.0 +64.0 

4.4 +2.5 +62.0 

7.9 -4.0- +55.2 

11.2 -4.0 +55.1 

14.4 -20.0 +39.0 

18.0 -14.5 +44.5 

TX 6 RX ANTS HMD 

COLLl NEAR 

08M H(DB) I(0B) 

TX 6 RX ANTS HMO 

BROADSIDE (AXkAL) 

DBM H(0B) I(DB) 

H in DB ABOVE IuA/M 

I In 08 ABOVE luA 
W-l 

4 z ~$2 

$55 %#LL 

$25 
100 

FREQUENCY-MHZ 

TABLE 42 

REDUCED VHF ELECTR~C FIELD STRENGTH DATA TAKEN ON A 

SWEPT-FREQLIWCY BASIS ON A 195 FOOT PATH IN 5000-LEVEL 

NORTH CROSSCUT 1 WATT TRANSMIT POWER - PRACTICAL WIP 

HORIZONTAL POLARIZATION 

OW E(DBA9OVE IuVhl) 

VERTICAL POLAR I ZATLON 

DBM E(D9 ABOVE I uV/M) 

-72.0 +32.7 

-47.0 +56.1 

-38.0 69.2 

-43.0 +65.7 

-42.0 60.1 

-54.0 +48.7 

-48.0 +54.6 

-36.0 69.1 

-39.0 +72.5 

-56.5 +54.3 

-52.0 62.2 

-45.0 68.8 
TABLE 43 

EWCED UHF ELECTRIC FIELD STRENGTH DATA TAKEN 014 A 

SWEPT-FREQUENCY BAS IS ON A 195 FDOT PATH IN 3000-LEVEL 

NDKM CROSSCUT 1 WATT TRANSMIT POWER - PRACTICAL WHIP 

ANTENNAS -- HECLA CON-S l t M l NE 

HORIZONTAL POLARIZATION 

OEM E(DB ABOVE luV/M) 

-54.0 +54.5 

-48.0 +69.1 

-40.0 +82.9 

-36.0 +87.3 

-44.0 +84.7 

-41 .O +89.5 

-36.0 +97.5 

-35.0 +100.6 

-34.0 +98.8 

VERTICAL POLARIZATION 

OBM E(08 ABOVE IuV/M) 

-54.0 +54.5 

-40.0 +77.1 

-35.0 +87.9 

-31 .O +92.3 

-31 .O +97.7 

-53.0 +77.5 

-50.0 +83.5 

-33.0 +102.6 

-30.0 +102.8 
.5 A- - 1.0 

- A toooolz SET MGE-KI LOFEET 

0- - - - 0 650 KHZ TEST SET 

El 520 KHZ TEST SET 

0 - . . . . . . .Q 300 KHZ TEST SET 
FIGURE 89 

REDUCED MF MAGNETIC FIELD STRENGTH DATA TAKEN 

ON 3000 LEVEL TOWARD CON-SIL WINZE USING 

COLLINS 520 KHz FM RADIO AND 650 KHz TEST SET 

I WATT TRANSMITTERS 

. . HECLA CON-SIL MINE 

.5 1 .o 

RAIUGE- KI LDFEET 
TABLE 44 

LOCATION 

1 

2 

3 

4 

5 

6 

7 

REDUCED MF W b4AG!.IETIC FIELD STRENGTH DATA TAKElJ ON A 

SIEPT-FREQUENCY RASlS ON A 195 FOOT PATH IW THE 3000-LEVEL 

,'10R7H CROSSCLIT OF HECLA CON-S I L Fll ME US I NC: I WATT TEST 

SYSTEM EQIII PMEVT 

CURRENT PRDBE REFERENCE' DATA 

FREQ(KHZ) S I NGER RX(0BuV) CF I (DB) 

300 +9.5 on +40 49.5 - 11.0 38.5 DeuA 

520 +19.@ on +60 99.0 - 12.6 = 86.4 DBuA 

650 +8.8 on +60 68.8 - 13.0 55.8 DBuA 

1000 +18.6 on +40 58.6 - 13.5 = 45.1 DBuA 

650 KHz 520 KHz 300 KHz 1 OOOKHZ 

S l NGER H(DB) SINGER H(DB) SINGER H(DB) SINGER H(DB) 

5.0 PRESENTATION OF RAW SWEPT-FREQUENCY DATA 

This section presents all the raw swept-frequency oscillographs taken 

during the program in the individual mines. Raw CW data have been 

presented in tabular form in conjunction with their reduced 

counterparts in Section 4.0. 

5.1 RAW DATA FROM OCCIDENTAL LOGAN WASH MINE 

The MF data taken at test ranges of 120 and 240 feet is given in 

Figure 91. 

The EF data taken at a test range of 120 feet is given in Figure 92. 

The VHF data taken at test ranges of 120 and 240 feet is shown in 

Figures 93 and 94 respectively for vertical and horizontal 

polarization with axial polarization dta being shown for the 240-foot 

range in Figure 95. 

The UHF data taken at the 240-foot test range is given in Figures 96 

and 97 respectively for vertical and horizontal polarization. 


b- I- 1aw 

<NU 

- ozu 

czo 

WJP. 

uo- 

>c- 
- 

6 

-1 - - / a++ +a u $:? 

-co 

ElOON 

=cL- 


--1 LL! =c z 

fc 

c.9 

- I lx LO 0 a 

3 
5.2 RAW DATA FROM UNITED NUCLEARfHOMESTAKE PARTNERS SECTION 23 MINE 

The MF data taken in the Wagner and 650 track test areas is given 

respectively in Figures 98 and 99. 

The HF data taken in the Wagner test area is given in Figure 100. 

The VHF data taken in the Wagner and 650 track test areas is given 

respectively in Figures 101 and 102. 

The UHF data taken in the Wagner and 650 track test areas is given 

respectively in Figures 103 and 104. 
OR1 GINAL OSCl LLOGRAPHS OF MF SWEPT-FREQUENCY 

DATA TAKEN IN WAGNER AREA OF UbIITki, I4UCLEAH 

SECTION 23 IfINE ' 

TX CURRENT PROBE - RX ANTENNA UNDER 480 VAC TX ANTENNA - TX AND RX ANTENNAS 

LINE 1.5 MTERS CENTER-CENTER LINE 1.5 METERS CENTER-CENTER 

TX ANTENNA - TX ANTENNA 1.5 METERS UNDER 480 TX ANTENNA - TX h RX ANTENNAS A

VAC 1 INF - RX ANTFNNA 7.6 M @ ORIFT CFNTFR TION - TX ANTENNA 1.5 METERS UN

LlNE - RX ANTENNA 2.6 METERS @ 
ORIGINAL OSCILLOGRAPHS OF MF SWEPT-FREQUENCY 

DATA TAKEN IN 650 TRACK AREA OF UNITED NUCLEAR 

SECTION 23 MINE 

TX CURRENT PROBE - RX ANTENNA WlTH FLAT SIDE 

AGAINST MSH 0.3 MITERS CENTER-CENTER 

TX ANTENNA - TX ANTENNA IN DRIFT CENTER 4.5 

METERS CENTER-CENTER - RX ANTENNA WlTH FLAT 

SlDE AGAINST MSH 0.3 METERS CENTER-CENTER 

NOTE: CURRENT PROBE ON PHONE LINE 

- 216 - 
Fl GURE 100 

9EIGINAL OSCILLOGWPHS OF HF SWEPT-FREQUENCY 

DATA TAKEN IN WAGNER AREA OF SECTION 23 MINE 

TX CURRENT PROBE - RX ANTENNA UNDER 480 VAC 

LINE 1.5 METERS CENTER-CENTER 

480 VAC CABLE - RX ANTENNA TIP ON CABLE 

, , ,\,, , &,.,..~ , .- -. - - -- - 

480 VAC CABLE - RX ANTENNA AT DRIFT CENTER 

2.6 METERS CENTER-CENTER SPACING 

- 217 - 
FIGURE 101 

ORIGINAL OSCILLOGRAPHS OF VHF SWEPT-FREOUENCY 

DATA T9KEN IN WAGNER AREA OF UNITED NUCLEAR 

SiCTf'j': 23 'll'!E 

HORIZONTAL BROP,DSIOE ORIENTATION 

VERTICAL ORIENTATION 

HORIZONTAL COLLINEAR ORIENTATION 
OR1 GlNAL OSCl LLOGRAPHS OF VHF SWEPT-FREQUENCY 

DATA TAKEN IN 650 TRACK AREA OF UNITED HUCLEAR 

SECTION 23 MINE 

VERTICAL ORIENTATION 

HORIZONTAL BROADSIDE ORIENTATION 
FIGURE 103 

OR1 GI NAL OSCl LLOGRAPHS OF UHF SWEPT-FREOUENCY 

DATA TAKEN IN WAGNER AREA OF UNITED NUCLEAR 

SECTION 25 MINE 

HORIZONTAL BROADSIDE ORIENTATION 

VERTICAL OR1 ENTAT ION 

- 220 - 
FIGURE 104 

OR1 GINAL OSCl LLOGRAPHS OF UHF SWEPT-FREQUENCY 

DATA TAKEN IN 650 TRACK AREA OF UNITED NUCLEAR 

SECTION 23 halNE 

HORIZONTAL BROADSIDE ORIENTATION 

VERTICAL OR1 ENTAT ION 
5.3 RAW DATA FROM KERR-MCGEE HOBBS POTASH FACILITY MINE 

The MF data taken at the 150 and 300 foot test ranges is given 

repectively in Figures 105 and 106. 

The HF data taken at the 150 and 300 foot test ranges is given 

respectively in Figures 107 and 108. 

The VHF data taken at the 150 and 300 foot test ranges is given 

respectively in Figures 109 and 110. 

The UHF data taken at the 150 and 300 foot test ranges is given 

respectively in Figure 111. 

The MF current probe coupled data at 300 foot test range is shown in 

Figure 112. 

LEFT: 

RIGHT: 

COPLANAR 

H FD 

COPLANAR 

V MD 

FIGURE 106 

MED l llM FREQUENCY SWEPT F l ELD STRENGTH 

OR1 GI NAL OSCI LLOGRAPHS - KERR F4Cf*E 

HOBBS POTASH FAC I I I TY 

Fl GURE 108 

tf l C*l FRFOIIENCY SWFPT r l ELD STRFFImH OPI G I NAL OSCI LLOf;R4PI1S 

KFI<R-ECGEF tlORRS POTASH FACILITY lllNE 300 FEET RANGE 
FIGURE 109 

VHF SWEPT FREQUENCY Fl ELD STRENIXH ?PI GI :I! 

OSCILLOGXAPYS - KE9P \"GEE HOBBS "3T;SH CACILITY 

150 FEET RANGE 

UHF SWEPT FREOUEYCY Fl ELD jT2.ELIC;TH 32 1 I1- I 'IAL 

OSC l LLOGRAPHS - KER? %GEE HOaDS DOTASH FAC I L l TY 

150 FEET RANC*I 
FIGURE 112 

MEDI Ilk1 FREOIJENCY SWEPT Fl ELD STRENGTH r)RI GINAL OSCl LLOGR

KERR KEE HOBRS POTASH FACILITY 300 FEET RANGE 

CIIRRENT PROBE EXCITATION 
5.4 RAW DATA FROM AMAX LEAD CO. OF MISSOURI BUICK MINE 

The MF and HE data taken at the 064 ore pass location is given 

respectively in Figures 113 and 114. 

The MF and HE data taken at the 049 ore pass location is given 

respectively in Figures 115 and 116. 

The VHF and UHF data taken at the 064 ore pass location is given 

respectively in Figures 117 and 118. 
ORIGINAL OSCILLOGRAPHS OF YF SWEPT-FREQUEVCY 

DATA AT 064 ORE PASS; TX AT NORTH MIWE Y 

AhAAX LEAD CO. BlJ lCK 441 FIE 

TX PROBE - RX PROBE 

TX PROBE - RX ANTENNA 

TX ANTENNA - RX ANTENNA 

- 232 - 
t I [-IJKF I I a 

OR1 GI VAL OSCI LLOGRAPHS OF HF S'VIEPT-FREOUENCY 

DATA AT 064 ORE PASS; TX AT WORTH MINE Y 

ALAAX I FAD CO. 9111 CK *,$I NE 

TX PROBE - RX PROBE 

TX PROBE - RX ANTENNA 

TX ANTENNA - RX ANTENNA 

- 777 _ 
FlGURE 115 

ORIGINAL OSCILLOGRAPHS OF MF SWEPT-FREQUENCY 

DATA AT 049 ORE PASS ; TX AT NORTH 1" NE Y 

AMAX LEPD CO. BI!ICK MINE 

TX PROBE - RX PROBE 

TX PROBE - RX ANTENNA 

TX ANTENNA - RX ANTENNA 
ORIGI VAL OSCI LLOGRAPHS OF HF WEPT-FREOUELICY 

DATA AT 349 ORE PASS; TX AT 'JORTH VINE Y 

AMAX LEAD CO. BUlCK b'I NE 

TX PROBE - RX PROBE 

TX PROBE - RX ANTENNA 

TX ANTENNA - RX APITE'JNA 
ORIGINAL OSCILLOGRAPHS OF VHF SWEPT-FREQUENCY 

DATA TAKEN IN THE NORTH MINE TRACKED HAULAGEWAY AT THE 064 ORE PASS; TX LOCATED AT Y 

MAX LEAYn PO. 5I.IICK MINE 

HORIZONTAL POLARIZATION 

VERTICAL POLAR1 ZAT I CN 
Fl GIIRE 11 8 

oRI GIIIAL OSC l LLOGRAPHS OF UHF SWEPT-FREOUENCY 

DATA TAKEN IN THE NORTH MINE TRACKED HAULAGE-. 

WAY AT THE 064 ORE PASS; TX LOCATED AT Y 

K14X LE43 CO. -"1P,% "l'!; 

HORIZONTAL POLARIZATION 

VERTICAL POLARIZATION 

- 237 - 
5.5 RAW DATA FROM MAGMA COPPER CO. SAN MANUEL MINE 

The MF and HF data taken in the car-cleaner drift is given 

respectively in Figures 119 and 120. 

The VHF and UHF data taken in the car-cleaner drift is given 

respectively in Figures 121 and 122. 

The 520 KHz CW test oscillographs is given in Figures 123 through 130. 

The 145 KHz CW test oscillographs is given in Figures 131 through 133. 
OR1 GI I4AL OSC I LLOGRAPHS OF MF SWEPT-FREQUENCY 

DATA TAKEN ON CAR-CLEANER TRACK DRIFT 

'IAGk'A COPPE2 C.O. SA?J *!AIIUEL !'IYE 

TX 8 RX ANTENNAS VMD,RX AT I-FT, TX AT I-FT 

TX 8 QX AYTENNAS COPLANAR HMD I. I M ABOVE TRACK TX 8 RX ANTENNAS VPID, RX AT 4-FT, TX AT I-Fl 

- 239 - TX 8 RX ANTENNAS VhlD, RX AT 9-FT, TX 4T I-FT 
ORIGINAL C 

D4TA TAKEY 

'lAC;IAA 

FIGURE 120 

SCI LLOG?A?b OF HF SWEPT-FREOUENCY 

OF CAR-CLEANER T?ACK DRIFT 

COPPER C3. SAN MANUEL ??!YE 

TX 8 RX ANTENNAS VMD, RX AT I-FT, TX AT I-FT 

TX % EX ANTENNAS COYLANAR HWD 1.1 '4 ABOVE TRACK TX & RX ANTENNAS VMD, RX AT 4-FT, TX AT I-FT 

- 240 - TX 8 RX APJTENNAS VVD, RX AT 8-FT, TX AT I-FT 
OR1 GlNAL OSCl LLOGRAPHS OF VHF SWEPT-FREOUEIdCY 

DATA TAKEN IN THE CAR-CLEANER TRACKED DRIFT 

"AGI'A COPPER CO. SAll ''qkIUEL L'INE 

HORl ZONTAL POLAR1 ZAT l ON 

- ~. ~ 

VERTICAL POLARIZATION 
OR1 GlNAL OSCl LLOGRAPHS OF UHF SWEPT-FREI)UEi.ICY 

DATA TAKEN IN THE CAR-CLEAFIER TRACKED DRIFT 

VPL:P4A VPPCR CO. SAN MANUEL MINE 

HORIZONTAL POLARIZATION 

VERTICAL POLARIZATION 
ORIGINAL OSCILLOGRAPHS FROM 520 KHZ CARRIER 

PHONE TESTING, VEHICLE-SASE LOCATIONS A - C 

MAW CFQ?P CC). SP:! 'fhMEL Elt:E 

LOCATION A LOCAT ION C 

XMlT FROM LOCO MACHINE SHOP, ZOW IN VEHICLE CI,CAR<LEANER TURNOUT;3-COG DEPARTURE 

ANTENNA SAM LEVEL 

LOCAT ION B 

F I RST TURPIOUT 

LOCATION C 

C2,AFTER 3-WG DEP; WBILE CANNOT HEA8 

BASE 

:IOTE : 'ECE I YE "9EAW :JOT USED AT THESE LOCAT IONS 
ORIGINAL OSCILLOGRAPHS FROV 520 KHz CARRIER 

PHONE TESTIFJG,VEHlCLE-BASE , LOCATIONS D - G 

%*Gar? CC)-F7 CO. SAil MANLFL :4ISE 

LOCATICN D LOCATION F 

ABOUT 500 FT ALONG SOUTH HAULAGE PAST MIDWAY BETWEEN 3-M)G DEP 6 17 SOUTH 

3-DOG DEPARTURE 

P 'r r +$ 4.AiibL .a ., 11- r., J' .U, ~1~3) 

LOCATION E LOCAT ION G 

AeOIJT 1000 FT ALO?IG SOUTH HAULAGE PAST GI, PANEL 17, WIN CROSSCUT 

3-M)G OEPARTURE 

'4~7:: 1' ""EA'P 'ICT lLSil) AT THESE LOCATlOlJS 
Fl GURE 125 

ORIGINAL 0SClLLOGRAPHS FRO\' 520 KHz CARRIER 

PHONE TEST1 NG, VEH ICLE-BASE , LOCAT1 ONS G - J 

&%AC?A COPPER C9. SAbI 'WAUEL IAI'IE 

LOCATION G LOCATION I 

G2, 17 SOUTH, t4OISY PANEL 17 

LOCAT ION H LOCAT l ON J 

PANEL 17, VAIN CROSSCU PANEL 17 NORTH 

bJOTE: RECEIVE PQEA'J? 'JOT IJSF9 AT LOCATIONS C. 8 H; 4LL LOCPTlO*IS TbESEAFTE" 11Si3 

TPE PFEAPP w ITI-I 33 Da GAI h~ 
FIGURE 126 

OR1 GlNAL OSCl LLOGRAPHS FROM 520 KHz CARRIER 

PHONE TESTING, VEHICLE-BASE , LOCATIONS K - M 

LIAUIA COPPER CO. SAN MAYUEL 'IIINE 

LOCATION K LOCAT ION L 

KI, PANEL 17 VAIN TOWARD 20 CROSSOVER 

LCCATION K LOCATION W 

G!, WIN LINE 17 NORTH/.? HAULAGE NORTH HAULAE-!,CHANGED ANTENNA LOCATION 
ORIGINAL OSCILLOGRAPHS FROM 520 KHz CARRIER 

PHONE TESTING, VEHICLE-BASE, LOCATIONS N - Q 

MAGMA COPPER m. S,4N ?IP!!L';'L'EL !!I NE 

LKATI CN N LKATI (W P 

JUST AFTER 20, SEVERAL HUNDRED FEET 100 FT PAST 30 CROSSOVER 

LCCATiOtI 5 

OLS DISPATCH SHACK 
FIGURE 128 

OR1 GlNAL OSCl LLOGRAPHS FROhr 520 KHz CARRIER 

WObIE TESTING, VEHICLE-BASE, LOCATIONS R - S 

YAGh4A COPPER CCI. SAIl L.?AYUEL h!lNE 

LOCATION R LOCATION S 

R1,5-SHAFT TURNOUr,PORTABLE(I-2 FT FROM WIRE) SI,AIR WORS,PORTABLE(I-2 FT FROM WIRE) 

LOCATION R LCCAT I CN S 

R~,~-SHAFT TURHOLT,VEHICLE S2,A IR WGRS, VEIHICULAR 
FIGURE I29 

ORI GIPIAL OSCI LLOGRAPHS FROP 520 KHz CARRIER 

PHOLIF TESTING, VEHICLE-BASE, LOCATIONS T - v 

I'AG'JA COPPER CO. SAV h'AA"IIJEL 'II'JE 

LOCAT1 ON T LOCAT104 V 

BETWEEN AIR WORS VI,ZND SET OF AIR DOORS,PORTABLE(I-2 FT,WIRE) 

ILKATION U L.OCAT10N V 

AFTER AIR DOORS V2,Z:dD SET OF AIF' DOORS, VEPICULAP. 
Fl GURE 130 

ORIGINAL OScl LLOGRAPHS FROM 520 KHz CARRIER 

PHONE TESTING, VEHICLE-BASE , LOCATIONS W - X 

"AGb'A C9PPER Cc). SArl :'AVUEL <'I NE 

LCCATION W LOCATION W 

wI,?ORTABLE,3-CHARLIE DEPARTURE,VERT LOX W3,SCHARLIE DEPARTuRE,vEHICULAR 

LOCATl ON W LOCATIO?I X 

w2,FCHARLIE OEPARTURE,PORTABLE()-2 FT,WIRE) 

HORI Z3h!T4L L30P PORTABLE ,OUTS I DE LOCO SHOP, 1-2 FT FROb,! W I F 
FIGURE 131 

ORIGINAL OSCILLOGRAPHS FROM 145 YHZ CARRIER 

PHONE TESTING, BASE-VEHICLE LOCATIONS G - K 

,IAGL% COPPE9 CO. SALl h4kkl~~~~ ''!':r 

LOCATION G LOCATION K 

GI,NOISE, 17 SOUTH, ?-MITERS FROM WIRE KI,NOISE PLUS 190 KHz, 17 SOUM END 

LOCATION G LOCAT ION K 

G2,17 SOUTH K2,AFTER 17-YORTH SWITCH 
ORIGINAL OSCILLOGRAPHS mOM 145 KHz CARRIER 

PHONE TESTING, BASE-VEHICLE LOCATIONS M - Q 

MA rn~ CO. se4 r+kr , &>UEL MINE 

LOCATION M 

MI,NOISE, NORTH HAULAGE-I 

LOCATION 0 

LOCATION M LOCATION Q 

M~,NORTH HAULAGE-I QI,NOISE, NEAR 5-SHAFT TURNOUT 
FIGURE 133 

OR1 GlNAL OSCl LLOGRAPHS FKJb" 45 KHz CARRIER 

PHONE TESTING, BASE-VEHICLE , LOCATIONS Q - X 

!4A6YrE, WWER CO. SrVi ,X,?NCEt ;?I!JE 

LOCATION Q 

02,NEAR 5-SHAFT TURNOUT 

LOCAT ION X 

OUTSIDE LOCO SHOP 
5.6 RAW DATA FROM HECLA MINIXG CO. CON-SIL MINE 

The MF data for horizontal magnetic dipole (HMD) and current-probe 

excitations is given in Figure 134. Similar data for the vertical 

magnetic dipole (VMD) antenna orientations is given in Figure 135. 

The HF data for several antenna orientations is given in Figures 136, 

137 and 138. 

The VHF data for two receiving test locations is given in Figures 139 

and 140 . The UHF data for two receiving test locations is given in Figures 141 

and 142. 
ORIGINAL OSCILLOGRAPHS OF MF SWEPT-FREQUENCY 

DATA TAKEN ALONG 3000-LEVEL NORM CROSSCUT 

HMD 6 PROBE CONFIGURATIOKS 

HECLA CO'I-5 1 L I,,f lNE 

TX d RX ANTENNAS COPLANAR HMO; ANTENNAS AT TX d RX COPLANAR HMD; ANTENNAS I-FOOT A6 

DRIFT CENTER (MIDDLE) TRACK QOTTOM) 

TX 5 RX ANTENNAS BqOADSlDE HMO; ANTENNAS AT TX 6 RX CURRENT PRCBES DRIFT CENTER 
ORIGINAL OSCILLOGRAPHS OF MF SWEPT-FREQUENCY 

DATA ALONG 3000-LEVEL NORM CROSSCUT-VMD 

CONFl GUMTI ONS - HECLA C9N-S l L ibil idE 

TX a RX ANTENNAS VMD NEAR DRIFT BACK 

HORIZONTAL WITH WIRING BUNDLE (TOP) 

TX 8 RX ANTENNAS VMD AT DRIFT CENTER (MIDDLE) 

- 256 - 

TX 8 RX ANTENNAS VMD I-FOOT ASOVE TRACK (BOTTOM) 
ORIGINAL OSCILLOGRAPHS OF HF SWEPT-FREQUENCY 

DATA ALONG 3000-LEVEL NORTH CROSSCUT-HMD AND 

PROBE CONFIGURATIONS W/O FREQUENCY INDEX 

REFERENCE - HECLA CON-SIL VINE 

TX 6 RX CURRENT PROBES 

TX 8 RX ANTENNAS BROADS I DE HMD AT DRl FT CENTE9 - 257 - 

(MI DOLE) 
FIGURE 137 

ORIGINAL OSCILLOGRAPHS OF HF SWEPT-FREQUENCY 

DATA ALONG 3000-LEVEL NORTH CROSSCUT-VM) 

CONFIGURATIONS W/O FREQUENCY INDEX REFERENCE 

HECLA CON-5 I L :'IhlE 

TX & RX ANTENNAS VMD NEAR DRIFT BACK HORlZCNTAL 

WITH WIRE BUNDLING (TOP) 

TX 6 RX ANTENNAS VMD AT DRIFT CENTER (MIDDLE) 

TX 8 RX ANTENNAS VMD I-FOOT 4BOVE TRACK (BOTTOM) - 258 - 
FIGURE 138 

ORIGINAL OSCILLOGMPHS OF HF SWEPT-FREQUENCY 

DATA ALONG 3000-LEVEL NORM CROSSCUT-PROBE AND 

VMD CONFEURAT IONS W l TH FREQUENCY l NDEX 

REFERENCE 

HECLA CONrSIL MINE 

TX & RY CURRENT PROBES WlTH 0 DBM INDEX TX 6 RY CURRENT PROBES WITH 20 DBM INDEX 

TX 6 RX ANTENNAS VMD NEAR DRIFT BACK HORIZONTAL TX PROBE, FX ANTENNA-VMD NEAR DRIFT BACK 

WITH WIRING BUNDLE (TOP1 HORIZONTAL WITH W 1 Rl NG BUNDLE (TOP) 
FIGURE 139 

ORIGINAL OSCILLOGRAPHS OF VHF SWEPT-FREQUENCY 

DATA ALONG 3000-LEVEL NORM CROSSCUT WITH 

ANTENNAS AT DRIFT CENTER AT LOCATION 1 

TX d RX CURRENT PROBES 

TX d RX ANTENNAS VERTICAL POLARIZATION 

TX & RX ANTENNAS HOQIZONTAL POLASIZATtC!?l 
FIGURE 140 

ORIGINAL OSCILLOGRAPHS OF VHF SWEPT-FREQUENCY 

DATA ALONG 3000-LEVEL NORTH CROSSCUT WITH 

ANTENNAS AT DRIFT CENTER AT LOCATION 2 

HECLA cort-s~~ MIYE 

TX b RX ANTENNAS VERTlCAL POLARIZATION 

TX 6 RX ANTENNAS HORIZONTAL WLARlZATlON 

- 261 - 
FIGURE 141 

ORIGINAL OSCI LLOGRAPHS OF LHF SWEPT-FREQUENCY 

DATA ALONG 3000-LEVEL NORTH CROSSCUT WITH 

AKTENNAS AT DRIFT CENTER AT LOCATION 1 

FlECLA CON-SIL MINE 

TX 6 RX ANTENNAS VERTl CAL POLAR I ZATI ON-BAND I TX & RX ANTENNAS VERTICAL POLARI ZAT~ON -BAND 2 

TX d RT ANTENNAS HORIZONTAL POLARIZATION-BAND I TX d RX ANTENNAS H3RIZOKTAL F3 LARIZATION-~ANC~ 

- 262 - 
FIGURE 142 

ORIGINAL OSCILLOGRAPHS OF UHF SWEPT-FREQUENCY 

DATA ALONG 3000-LEVEL NORTH CROSSCUT WITH 

ANTENNAS AT OR1 FT CENTER AT LOCAT I ON 2 

HECLA CON-SIL MINE 

TX & RX ANTENNAS VEml CAL WLARIZATION-BAND I TX b RX ANTENNAS VERTICAL POLAR1 ZATION-BAND i 

rX d RX ANTENNAS HORIZONTAL POLARIZATION-BAND TX d RX ANTENNAS HORIZONTAL POLARIZATION-BAND 2 

- 263 -