U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2006–5246

Questa Baseline and Premining Ground-Water Quality Investigation 15

Methods of Phase II and III Well Installation and

Development and Results of Well Logging, Hydraulic

Testing, and Water-Level Measurements in the Red

River Valley, New Mexico, 2002–04

Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15.

Methods of Phase II and III Well Installation 

and Development and Results of Well 

Logging, Hydraulic Testing, and Water-Level 

Measurements in the Red River Valley, New 

Mexico, 2002–04

By Paul J. Blanchard, James R. Bartolino, Lisa C. Donohoe, Douglas P. McAda, 

Cheryl A. Naus, and Roger H. Morin

Prepared in cooperation with the New Mexico Environment Department

Scientific Investigations Report 2006–5246

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

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Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Blanchard, P.J., Bartolino, J.R., Donohoe, L.C., McAda, D.P., Naus, C.A., and Morin, R.H., 2007, Questa baseline and 

pre-mining ground-water quality investigation 15.—Methods of phase II and III well installation and development 

and results of well logging, hydraulic testing and water-level measurements in the Red River Valley, New Mexico, 

2002–04: U.S. Geological Survey Scientific Investigations Report 2006–5246, 56 p.

Front cover: Jeffery Eman (left) and Arthur Clark (right), U.S. Geological Survey, Lakewood, Colorado, drilling shallow 

well near bank of Red River. Photograph taken by Cheryl Naus, U.S. Geological Survey, Albuquerque, New Mexico.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................2

Physical Description of Study Area...................................................................................................2

Climate and Vegetation........................................................................................................................2

Surface Water.......................................................................................................................................6

Hydrogeology.........................................................................................................................................7

Mining History .......................................................................................................................................8

Well-Numbering Systems....................................................................................................................8

Acknowledgments................................................................................................................................9

Well Location, Installation, Construction, and Development .................................................................9

Phase II Drilled Wells.........................................................................................................................10

Phase II Small-Diameter Wells.........................................................................................................10

Phase III Small-Diameter Wells .......................................................................................................12

Lithologic and Geophysical Well Logging................................................................................................12

Lithologic Logging...............................................................................................................................12

Geophysical Logging..........................................................................................................................12

Hydraulic Testing to Determine Aquifer Characteristics ......................................................................28

Flow-Meter Survey in Well SC–7A...................................................................................................28

Slug Tests Conducted in Selected Phase I and II Drilled Wells..................................................28

Pumping Test Conducted at Mouth of Straight Creek Drainage.................................................30

Water-Level Measurements ......................................................................................................................30

Summary........................................................................................................................................................53

References....................................................................................................................................................55

Figures

1–5. Maps showing location of:

1. Study area in Red River Valley, north-central New Mexico, and features of study 

area ........................................................................................................................................3

2. Hottentot well .......................................................................................................................4

3. Straight Creek and Advanced Wastewater Treatment Facility wells .........................5

4. La Bobita and Hansen Phase II wells and Phase III wells ...........................................6

5. Capulin Canyon Phase II wells ..........................................................................................7

6. Diagram showing well-numbering system in New Mexico...................................................9

7. Diagrams showing well-completion data and lithologic logs for Hottentot, Hansen, 

La Bobita, CC–1B, and CC–2B wells ........................................................................................13

8. Diagrams showing well-completion data, lithologic logs, and geophysical logs for 

SC–6A, SC–7A, and SC–8A wells .............................................................................................18

9. Diagram showing vertical distribution of borehole flow measured during pumping and 

corresponding percentage of flow into well SC–7A.............................................................29
iv

10–14. Graphs showing:

10. Water levels in wells AWWT–1, SC–5A, SC–5B, SC–7A, and SC–8A before, during, 

and after pumping test and comparison of water levels in well AWWT–2 to 

barometric pressure, November 22–December 5, 2003..............................................31

11. Daily mean streamflow and stage of the Red River near Questa and ground-water 

altitudes in wells SC–6A, SC–7A, and SC–8A, February 2003–June 2004 ................33

12. Ground-water altitudes in Hottentot, Hansen, and La Bobita wells, February 

2003–June 2004 ..................................................................................................................34

13. Ground-water altitudes in wells CC–1A, CC–1B, CC–2A, and CC–2B, February 

2003–April 2004...................................................................................................................35

14. Difference between ground-water altitudes in La Bobita and Phase III wells and 

altitude of water in Red River, May 13 and June 2–3, 2004.........................................53

Tables

1. Locations, altitudes, construction information, and initial water levels for Phase II and 

III wells, Red River Valley, north-central New Mexico, 2002–04 ........................................11

2. Estimated hydraulic-conductivity values for slug tests conducted June 3–5, 2003, for 

selected wells in Red River Valley, north-central New Mexico .........................................29

3. Results of pumping test conducted December 3–4, 2003, in selected wells in Red River 

Valley, north-central New Mexico...........................................................................................32

4. Altitude of water levels in Phase I, II, and existing Advanced Wastewater Treatment 

Facility wells, Red River Valley, north-central New Mexico, 2002–04 ...............................36

5. Altitude of water levels in La Bobita and Phase III wells and concurrent altitude of 

stage of Red River, north-central New Mexico, 2003–04.....................................................50
Conversion Factors and Datums

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2)

square foot (ft2) 0.0929 square meter (m2)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L)

Flow Rate

foot per day (ft/d) 0.3048 meter per day (m/d)

foot squared per day (ft2/d) 0.09290 meter squared per day (m2/d) 

foot squared per minute (ft2/min) 0.09290 meter squared per minute (m2/min) 

gallon per minute (gal/min) 0.06309 liter per second (L/s)

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) 

Mass

ton 0.9072 megagram

Ohm-meters (ohm-m) can be converted to microsiemens per centimeter (μS/cm) by the equation

(1/ohm-m) x 0.0001=μS/cm.

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F= (1.8×°C) +32.

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C= (°F-32)/1.8.

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 

(NGVD 29).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.
vi
Abstract

In April 2001, the U.S. Geological Survey and the New 

Mexico Environment Department began a cooperative study to 

infer the pre-mining ground-water chemistry at the Molycorp 

molybdenum mine site in the Red River Valley of northcentral New Mexico. This report is one in a series of reports 

that can be used to determine pre-mining ground-water conditions at the mine site. 

Weathering of hydrothermally altered bedrock in the 

study area has resulted in steep, highly erosive, and sparsely 

vegetated scar areas that are clearly visible from the ground 

and in aerial photographs. Runoff from intense summer rainfall over tributary drainages containing scar areas can transport 

large quantities of sediment and form debris fans where these 

tributaries join the Red River. 

Twenty-nine observation wells were installed in three 

phases as part of this study in the Red River Valley and tributary drainages. Eight Phase II observation wells were drilled 

using an air-rotary/hammer rig. Three Phase II and 10 phase 

III small-diameter wells were installed using a direct-push 

rig. Lithologic logs were recorded for all eight Phase II 

drilled wells. Borehole geophysical logging (including natural 

gamma, induction, and single-detector neutron) was conducted 

in three Phase II wells. 

Aquifer tests conducted during 2003 to estimate the 

hydraulic properties of debris-flow and Red River alluvial 

deposits in and near Straight Creek included a flow-meter 

survey, slug tests, and a pumping test. Results of a flow-meter 

survey in well SC–7A indicated that about 77 percent of the 

water entered the well from a 10-foot-thick zone near the top 

of the screened interval and about 23 percent of the water 

entered the well from a 15-foot-thick zone near the bottom 

of the screened interval. Slug tests, performed in 11 wells 

during June 3–5, 2003, indicated that the mean and median 

estimated hydraulic conductivities for debris-flow deposits 

were 15.25 and 15.35 feet per day, respectively, for bedrock 

were 0.12 and 0.08 feet per day, respectively, and for mixed 

debris flow and Red River alluvium were 73–207 (estimated 

range) and 80 feet per day. In general, bedrock has the smallest hydraulic conductivity, debris-flow material has the next 

highest hydraulic conductivity, and mixed debris flow and Red 

River alluvium has the largest hydraulic conductivity. A pumping test conducted December 3–4, 2003, using well AWWT–1 

as the pumped well, and wells AWWT–2, SC–5A, SC–5B, 

SC–7A, and SC–8A as observation wells, indicated estimated 

transmissivity of 12,000 to 34,000 feet squared per day and 

estimated hydraulic conductivity of 230 to 340 feet per day.

Water-level measurements in wells SC–6A, SC–7A, 

SC–8A, and the Hottentot, Hansen, and La Bobita wells show 

that water levels typically rose rapidly during melting of the 

winter snowpack in the springtime and then generally declined 

during the rest of the year. The water-level rise in response 

to spring snowmelt occurred earlier and was smaller at larger 

distances from the Red River. Differences between the stage 

in the Red River and water levels in wells SC–8A and SC–9A, 

and the absence of water in well SC–9A at the time of well 

completion, indicate that the Red River has a poor hydraulic 

connection to the underlying ground-water system and the surface-water system is perched above the ground-water system 

at this site. Water levels in Phase III wells indicate that the 

Red River and the shallow ground-water system are connected 

hydraulically from near wells 4–1D and 4–1S downstream to 

near wells 2–1 and 2–2 but are poorly connected near the La 

Bobita well and well 1.

Introduction

In April 2001, the U.S. Geological Survey (USGS) and 

the New Mexico Environment Department began a cooperative study to infer the pre-mining ground-water chemistry at 

Questa Baseline and Pre-Mining Ground-Water Quality 

Investigation 15.—Methods of Phase II and III Well 

Installation and Development and Results of Well Logging, 

Hydraulic Testing, and Water-Level Measurements in the 

Red River Valley, New Mexico, 2002–04

By Paul J. Blanchard, James R. Bartolino, Lisa C. Donohoe, Douglas P. McAda, Cheryl A. Naus, and 

Roger H. Morin
the Molycorp molybdenum mine site in the Red River Valley 

in north-central New Mexico (fig. 1). This study was prompted 

by the Water Quality Act, under the jurisdiction of the New 

Mexico Water Quality Control Commission that requires a 

mine operator to develop and complete an approved closure 

plan that prevents the exceedence of (1) standards set forth in 

New Mexico Water Quality Control Commission Regulations 

(§20.6.2.3103 New Mexico Administrative Code) or (2) natural background water-constituent concentrations. 

The Molycorp molybdenum mine has operated intermittently since the 1920s; ground-water-level and water-quality 

data were not obtained prior to initiation of mining. To infer 

pre-mining ground-water chemistry, observation wells were 

installed in three phases in unmined areas that were judged 

to be analogs to the mine site. During Phase I wells were 

installed in the Straight Creek drainage (Naus and others, 

2005) and during phases II and III wells were installed in 

five additional areas. The five areas were Hottentot Creek, 

Straight Creek, Hansen Creek, near La Bobita campground, 

and Capulin Canyon. The Hottentot Creek, Straight Creek, and 

Hansen Creek drainages (figs. 1, 2, 3, and 4) contain debrisflow deposits associated with scar areas. The La Bobita (fig. 4) 

drainage contains unconsolidated deposits in a non-scar area 

characterized by propylitic alteration. Capulin Canyon (figs. 1 

and 5) contains shallow unconsolidated deposits overlying 

bedrock in a non-scar area. The existing ground-water conditions in these five analog areas were used to establish baseline 

ground-water conditions which, when combined with groundwater conditions in mined areas, can be used to infer pre-mining conditions at the mine site. 

Field observations indicated that the analog areas have 

been disturbed to varying degrees by non-mining anthropogenic activities. These activities include exploration drilling, 

road construction, power and telephone line construction and 

maintenance, forest service construction and maintenance, 

and residential, commercial, and municipal development. The 

Straight Creek drainage basin was selected as the primary analog area because of similarities of terrain and geology to the 

mine site, its accessibility and potential for well installation, 

and minimal anthropogenic disturbance.

Purpose and Scope

The purpose of this report is to document and describe 

Phase II and Phase III well installation and development, 

present results of lithologic and geophysical logging, present 

results of hydraulic testing to determine aquifer characteristics, 

and present and discuss water-level measurements collected 

during the period March 2002 through June 2004. Because of 

the size and complexity of the study area, this report is one in 

a series of reports that can be used to determine pre-mining 

ground-water conditions at the mine site. The results of these 

studies can help guide decisionmakers in establishing appropriate remedial actions at the Molycorp mine. 

Physical Description of Study Area

The Red River, a tributary to the Rio Grande, is located 

in north-central New Mexico (fig. 1). The area is a rugged 

mountainous terrain with steep slopes and V-shaped valleys. 

The main area of study within the Red River drainage basin 

extends west from the town of Red River to the USGS streamflow-gaging station near Questa (fig. 1) (station 08265000, 

Red River near Questa, New Mexico, referred to as the Questa 

gage). The area upstream from the Questa gage includes 

approximately 18 mi (miles) of the Red River and 108 mi2

(square miles) of the Red River drainage basin. The mine site 

is located east of the Questa ranger station to the north of the 

Red River and New Mexico State Highway 38 (fig. 1). The 

mine site covers approxi­mately 6 mi2 (U.S. Department of 

Agriculture Forest Service, 2001) and includes three primary 

tributary drainages to the Red River—Capulin Canyon, Goat 

Hill Gulch, and Sulphur Gulch (fig. 1). 

Hydrothermally altered bedrock is present in the Hottentot, Straight, Hansen, Little Hansen, Goat Hill, Sulphur, 

and Capulin drainages (fig. 1). Weathering of this bedrock 

has resulted in steep, highly erosive, and sparsely vegetated 

scar areas that are clearly visible from the ground and in aerial 

photographs. 

Mining activities have produced extensive underground 

work­ings and an open pit of approximately 162 acres (Naus 

and others, 2005) in and adjacent to Sulphur Gulch. Wasterock piles cover steep slopes on the north side of the Red River 

Valley between Capulin Canyon and Spring Gulch, a tributary 

valley of Sulphur Gulch. 

Climate and Vegetation

The Red River drainage basin is located within a semiarid desert that receives precipitation throughout the year 

and sustains moderate biodiversity. Between 1915 and 2002, 

the annual average temperature at the town of Red River 

was 4 °C, and the annual average precipitation and snowfall 

were approximately 20.5 and 146 in. (inch), respectively. The 

annual range of average daily temperatures at Red River was 

18 °C (Western Regional Climate Center, 2003). 

Climate and vegetation vary greatly within short distances, primarily because of differences in topography. Topography in the study area is steep, rising rapidly from the basinfloor elevation of approximately 7,450 ft (feet) at the Questa 

gage to ridge-crest elevations exceeding 10,500 ft. Orographic 

effects of mountainous topography lead to precipitation on the 

windward slopes and localized storms within the Red River 

drainage basin and tributary drainages. Precipitation from 

intense summer storms can cause soil mass wasting and debris 

flows in the scar areas that result in debris-flow deposits and 

debris fans at the mouths of many tributaries to the Red River 

(Kirk Vincent, USGS, written commun., 2003).

Dominant vegetation associations in the Red River Basin 

and the general elevation zones are piñon-juniper woodland 

   Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15
Figure 1. Location of study area in Red River Valley, north-central New Mexico, and features of study area.

Introduction 

Mine site 

Open 

pit 

Town ofRed River

Study area 

Study area

Questa Red River

drainage basin

NE

W

MEXICO

EXPLANA

Straight Creek scar 

TION

Hottentot Creek scar

Red River nearQuesta streamflowgaging station(08265000)

Questaranger station 

La Bobita campground

0

0

1.0 1.5 2.0 MILES 0.5

0.5 1.0 1.5 2.0 KILOMETERS

Area shown in figure 5 

36° 38’

41’

36° 44’

105° 33’ 30’ 24’ 27’ 105° 21’

Pioneer Creek

Goose Creek

Placer 

Creek

alette M r C eek

Bitter Creek

Bobcat Creek

Moreno 

Creek

Hematite Creek

Fourth of July Canyon

Black

Canyon

Rio

Pecos

Grande

River

MEXICO

TEXAS

Indexmap

June Bug scar

June Bug campground

Area shown in figure 3 

Area shown in figure 2 

Blind Gulch

a H nsen C er ke

na Heltti L nes

er C ke

Straight Creek

Hottenoto Creek

Area shown in figure 4 

Copper

eek Columbine Cr

Base compiled from U.S. Geological Survey Digital Raster Graphic Data 1:100,000, 1982, andfrom U.S. Geological Survey Digital Orthophoto Quadrangle, 1:12,000, 1998Universal Transverse Mercator projection, Zone 13Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83) Scar area

Phase I wellPhase II wellPhase III wellAdvanced Wastewater Treatment Facility well
Figure 2. Location of Hottentot well. 

   Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

250 500 FEET

50 100 METERS

0

0

36°42’30”

40”

36°42’50”

105°25’50” 105°25’40”

38

HOTTENTOT

EXPLANATION

HOTTENTOT Phase II well and name

Hottentot

Red River

Creek

Base compiled from U.S. Geological Survey Digital Raster Graphic Data 1:100,000, 1982, and

from U.S. Geological Survey Digital Orthophoto Quadrangle, 1:12,000, 1998

Universal Transverse Mercator projection, Zone 13

Horizontal coordinate information is referenced to the North American

 Datum of 1983 (NAD 83)
Figure 3. Location of Straight Creek and Advanced Wastewater Treatment Facility wells.

SC–9A

SC–8A

SC–7A

36°43’

45”

36° 42’ 30”

AWWT–1

Advanced Wastewater

Treatment Plant facilities

AWWT–2

SC–5B

SC–5A

SC–3B SC–3A

SC–2B

SC–4A

SC–6A

SC–1B

SC–1A

105° 26’ 45” 105° 26’ 30”

SC–5B

SC–9A

AWWT–1

Red River

Straight Creek

250 500 FEET

50 100 METERS

0

0

EXPLANATION

Scar area

Phase I well and identifier

Phase II well and identifier

Advanced Wastewater

 Treatment Facility well

Base compiled from U.S. Geological Survey Digital Raster Graphic Data 1:100,000, 1982, and

from U.S. Geological Survey Digital Orthophoto Quadrangle, 1:12,000, 1998

Universal Transverse Mercator projection, Zone 13

Horizontal coordinate information is referenced to the North American

 Datum of 1983 (NAD 83)

Introduction   
from 6,000 to 7,500 ft, mixed conifer woodland (primarily ponderosa and limber pine) from 7,500 to 9,000 ft, and 

spruce-fir woodland (primarily Douglas and white fir) from 

9,000 to 12,000 ft (Knight, 1990; Larry Gough, USGS, oral 

commun., 2003). 

Surface Water

The Red River originates at an altitude of about 12,000 ft, 

flows about 35 mi, and enters the Rio Grande at about 

6,600 ft. The total Red River drainage-basin area is 190 mi2; 

the drainage area upstream from the Questa gage is 108 mi2. 

Snowmelt flows typically begin in late March and peak in 

late May to mid-June. Summer thunder­storms are prevalent in 

July and August and can cause localized flooding and debrisflow movement. Between 1930 and 2001, the mean annual 

dis­charge of the Red River at the Questa gage ranged from 

12.8 to 103 ft3/s (cubic feet per second), the average daily discharge ranged from 2.5 to 750 ft3

/s, and the average discharge 

was 46.1 ft3/s (U.S. Geological Survey, 2004).

Figure 4. Location of La Bobita and Hansen Phase II wells and Phase III wells.

 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

36°42’

30”

36°43’

105°28’30” 28’ 30” 105°27’

2–2

1

2–1

2–1

3

4–1S

4–1D

4–2S

4–2D

4–3S

4–3D

38

LA BOBITA

HANSEN

0 1,000 3,000 FEET

0 250 500 750 1,000 METERS

2,000

Red River

Hansen

Creek

Little Hansen

Creek

Base compiled from U.S. Geological Survey Digital Raster Graphic Data 1:100,000, 1982, and

from U.S. Geological Survey Digital Orthophoto Quadrangle, 1:12,000, 1998

Universal Transverse Mercator projection, Zone 13

Horizontal coordinate information is referenced to the North American

 Datum of 1983 (NAD 83)

LA BOBITA

EXPLANATION

Scar area

Phase II well and name

Phase III well and identifier
Springs and shallow alluvial ground water discharge to 

the Red River, making the river a gaining stream over much of 

its length (Smolka and Tague, 1989). Between the town of Red 

River and the Questa gage, there are about 25 ephemeral seeps 

and springs along the banks of the Red River and approximately 20 intermittent seeps and springs in tributary drainages 

on the north side of the river (South Pass Resources, Inc., 

1995; Steffen, Robertson, & Kirsten, 1995; Robertson GeoConsultants, Inc., 2001). Flow from these springs and seeps 

affect the color and turbidity of the river. Aluminum hydroxide 

often precipitates downgradient from scar and mined areas on 

the north side of the Red River (Vail Engineering, Inc., 1989). 

In the Straight Creek drainage, the West Fork of Straight 

Creek flows perennially through most of its reach. The East 

Fork of Straight Creek and Straight Creek downstream from 

the confluence of the West and East Forks flow ephemerally 

and intermittently; streamflow typically infiltrates the debrisflow deposits upstream from this confluence. Streamflow in 

Straight Creek discharges to the Red River only during periods 

of peak snowmelt runoff and following intense precipitation. 

The downstream reach of the Straight Creek natural streambed 

has been reworked to divert flow around the east side of the 

Advanced Wastewater Treatment (AWWT) Facility, which is 

operated by the town of Red River.

 Hydrogeology

This section describes the generalized geology, geomorphology, and water-bearing units in the Red River Valley. 

Previous studies of the geology and mineralogy of the Red 

River Valley include those by Schilling (1956), Rehrig (1969), 

Lipman (1981), and Meyer and Leonardson (1990, 1997). The 

following discussion uses information from these sources, 

from Ludington and others (2005), and from USGS scientists 

participating in this study.

The Red River Valley is located along the southern edge 

of the Questa Caldera and contains complex structural features 

(Caine, 2003) and extensive zones of hydrothermal alteration. 

The geology of the basin consists of volcanic and intrusive 

rocks of Tertiary age, underlain by metamorphic rocks of 

Figure 5. Location of Capulin Canyon Phase II wells.

CC–1A CC–2A

CC–1B

CC–2B

36°42’30”

36°42’35”

105°32’15” 105°32’10”

0 100 200

0 25 50 75 100 METERS

300 FEET Base compiled from U.S. Geological Survey Digital Raster Graphic Data 1:100,000, 1982, and

from U.S. Geological Survey Digital Orthophoto Quadrangle, 1:12,000, 1998

Universal Transverse Mercator projection, Zone 13

Horizontal coordinate information is referenced to the North American

 Datum of 1983 (NAD 83)

West Fork Capulin Canyon

CC–1B

EXPLANATION

Phase II well and identifier

Introduction 
Precambrian age that were intruded by granitic stocks. The 

volcanic rocks are primarily intermediate to felsic in composition (andesite to rhyolite). Granites and porphyries that 

intruded the volcanic rocks were the apparent source of the 

hydrothermal fluids, rock alteration, and subsequent mineralization. Mineral deposits in the Red River Valley are considered climax-type deposits, which are associated with silicaand fluorine-rich rhyolite porphyry and granitic intrusives. 

Ore deposits in the Red River Valley contain quartz, 

molybdenite, pyrite, fluorite, calcite, manganiferous calcite, 

dolomite, ankerite, and rhodochrosite. Lesser amounts of 

galena, sphalerite, chalcopyrite, magnetite, and hematite also 

are present. The hydrothermal alteration related to mineralization overprints an older, regional alteration of rock. In these 

areas, rocks can contain a mixture of quartz, pyrite, and illite 

clays replacing feldspar, chlorite, carbonates, and epidote. 

Minerals occurring in waste rock produced by mining activities include chlorite, gyp­sum, illite, illite-smectite, jarosite, 

kaolinite, and muscovite (Gale and Thompson, 2001). 

Scar-area bedrock outcrops consist of andesitic volcanic 

and volcaniclastic rocks, rhyolitic tuff, quartz latite, and rhyolite porphyry. Most of the andesite and quartz latite has been 

hydrothermally altered and primarily contains plagioclase 

feldspar and chlorite. Rhyolite porphyry and tuff do not seem 

to have been substantially altered. 

Runoff from intense summer rainfall over basins tributary 

to the Red River can transport large quantities of sediment 

down tributary drainages and form debris fans where these 

tributaries join the Red River. Where the tributary drainages 

contain scar areas, the debris fans are large, indicate evidence 

of active deposition, and contain poorly sorted coarse gravel 

and cobble to clay-size sediments. Sediment transported and 

deposited by the Red River (Red River alluvium), in contrast, 

generally consists of medium- to well-sorted sand and gravel 

that consist of a mix of the bedrock lithologies found in the 

entire Red River drainage basin. Large debris fans debouching 

from tributary drainages have caused aggradation of the Red 

River streambed in river reaches upstream from debris fans 

(Kirk Vincent, USGS, written commun., 2005).

Important water-bearing units in the Red River Valley 

include fractured bedrock, debris-flow deposits, and Red River 

alluvium. Bedrock constitutes the largest aquifer in the study 

area in terms of rock mass but contains only small amounts 

of ground water because the rock has low porosity and most 

of the water occurs in fractures. Debris-flow deposits, debris 

fans, and Red River alluvium are smaller in area, but they 

contain most of the ground water in the valley. Debris-flow 

deposits, debris fans, and the Red River alluvium typically 

are less than 1,000 ft wide and less than 200 ft thick (Kirk 

Vincent, USGS, written commun., 2003). The largest debris 

fans have caused the Red River to aggrade upstream from the 

fans during the Quaternary; water flowing in these shallow 

aquifers likely passes alternately through Red River alluvium 

and debris-flow deposits (Kirk Vincent, USGS, written 

commun., 2003). 

Mining History

Molybdenite was discovered in Sul­phur Gulch in 1914. 

Subsequently, underground mining operations took place 

between 1919 and 1958; by 1954 there were more than 35 mi 

of underground mine workings (Robertson Geoconsultants, 

2000c; U.S. Environmental Protection Agency, 2000). Exploration of areas surrounding the mine was conducted following 

closure of the mine in 1958. By 1964, sufficient reserves had 

been identified to justify development of an open-pit mine in 

Sulphur Gulch and construction of a mill capable of processing 10,000 tons of ore per day. The first ore from the pit was 

delivered to the mill in December 1965 (Molycorp, Inc., 

2004). 

Overburden and waste rock from open-pit mining was 

deposited at several locations on the south-facing slopes 

north of the Red River between Capulin Canyon and Spring 

Gulch (Robertson Geoconsultants, 2000a, 2000c; URS, 2001). 

Beginning in 1964, tailings were transported by pipeline from 

the mine to the tailings facility near Questa. Water used in the 

mill operation was obtained from the Red River, the Red River 

alluvium, and from water collected during dewatering of the 

mine (URS, 2002). Approximately 328 mil­lion tons of waste 

rock were depos­ited at the tailings facility between 1964 and 

1983 (Steffen Robertson & Kirsten, 1995; Slifer, 1996; Robertson GeoConsultants, Inc., 2000b, 2000c).

Molycorp ceased open-pit mining in 1983 and initi­ated 

a new phase of underground mining in Goat Hill Gulch. This 

change effectively stopped the dumping of waste rock in 

Capulin Canyon; along the north slope of the Red River; and 

in Goat Hill, Sulphur, and Spring Gulches. It also increased 

the volume of tailings slurry transported by pipeline to the 

tailings facility.

While the underground mine was inactive during 

1992–95, ground water was not pumped from the underground 

mine workings, and the workings were allowed to partially 

reflood. The mine was dewatered and repaired when production resumed in late 1996, and mining of a new ore body 

began in 1998 (Molycorp, Inc., 2004).

Well-Numbering Systems

Two systems of numbering wells were used in this 

study—a study-specific system and a standardized New 

Mexico system. In the study-specific system, wells in Capulin 

Canyon and Straight Creek were assigned a two-letter abbreviation designating the drainage in which the wells were located 

(CC and SC), a sequence number, and a suffix of A if the 

well was completed in unconsolidated debris-flow or alluvial 

deposits, or a suffix of B if the well was completed in bedrock. 

The sequence number identifies a single well completed in 

either unconsolidated deposits or bedrock or a pair of wells 

where one well was completed in unconsolidated deposits and 

one well was completed in bedrock. For example, well SC–7A 

designates a well in Straight Creek completed in 

 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15
unconsolidated debris-flow or alluvial deposits, SC–2B 

designates a well in Straight Creek completed in bedrock, and 

wells SC–5A and SC–5B designate a well pair in Straight 

Creek completed in debris-flow/alluvial deposits and bedrock, 

respectively. 

In the study-specific system, Phase III wells were 

assigned a general site area (areas 1 through 4) in a downstream-to-upstream direction along the Red River. In areas 

1 and 3, only one well was drilled; each well was designated 

1 and 3, respectively. In area 2, two wells were drilled at different distances from the Red River and were designated 2–1 

and 2–2. In area 4, three pairs of deep (D) and shallow (S) 

wells were drilled and designated 4–1D and 4–1S, 4–2D and 

4–2S, and 4–3D and 4–3S.

The standardized system of numbering wells in New 

Mexico also was used to designate the location of wells in this 

report. The system is based on the common division of public 

lands into sections (fig. 6). The well number, in addition to 

designating the well, locates the position to the nearest 10-acre 

tract in the land network. This number is divided into four segments. The first segment denotes the township (T.) north (N.) 

or south (S.) of the New Mexico base line, the second denotes 

the range (R.) east (E.) or west (W.) of the New Mexico principal meridian, and the third denotes the section. The fourth 

segment of the number consists of three digits that denote section subdivisions of 160-, 40-, and 10-acre tracts, respectively. 

Each section is divided into four 160-acre quarter sections. 

The first digit of the fourth segment denotes the quarter section and is numbered 1, 2, 3, or 4, for the northwest, northeast, 

southwest, and southeast quarters. Similarly, each 160-acre 

quarter section is further divided into four 40-acre tracts 

numbered in the same manner, and the second digit denotes 

the 40-acre tract. Finally, each 40-acre tract is divided into 

four 10-acre tracts also numbered in the same manner, and the 

third digit denotes the 10-acre tract. Letters A, B, C, and so on 

are added sequentially to the fourth segment to designate the 

second, third, fourth, and succeeding wells in the same 10-acre 

tract. Well SC–1A, for example, is numbered 29N.14E.28.441 

and, therefore, is in the NW1⁄4 of the SE1⁄4 of the SE1⁄4 of section 28, township 29 north, range 14 east. 

Acknowledgments

The authors thank the study Advisory Committee for 

their contributions to the design and implementation of the 

study. Advisory committee members included Amigos Bravos, 

Molycorp, and the New Mexico Environment Department. 

Advice and cooperation from the U.S. Environmental Protection Agency Region 6 and the U.S. Forest Service are gratefully acknowledged. The authors thank Russell Church, Plant 

Supervisor, AWWT facility, the town of Red River, and the 

AWWT facility staff for providing access to their observation 

wells and assisting with field activity logistics. Assistance 

with data compilation and sample collection by Caroline Myer 

(USGS) is greatly appreciated.

Well Location, Installation, 

Construction, and Development

Twenty-nine observation wells were installed in three 

phases as part of this study in the Red River Valley and 

tributary drainages (figs. 2–5). Eight observation wells were 

installed in the Straight Creek analog site during Phase I 

(November 2001 through February 2002) (Naus and others, 

2005). Eleven additional wells were installed in the Hottentot, Straight, Hansen, La Bobita, and Capulin drainages 

during Phase II (October 2002 through January 2003). Ten 

small-diameter wells were installed in the Red River alluvium 

north of the Red River during Phase III (December 2003). 

Two existing wells (AWWT–1 and AWWT–2) at the town of 

Red River Advanced Wastewater Treatment Facility also were 

included in the monitoring-well network.

Phase I wells (SC–1A and B, SC–2B, SC–3A and B, 

SC–4A, SC–5A and B) were located in the Straight Creek 

drainage basin along the assumed path of ground-water flow 

in debris-flow deposits from the upstream part of the basin to 

near the mouth of the basin where straight Creek flows into 

Red River (fig. 3) (Naus and others, 2005). Wells SC–2B, 

SC–3A, SC–3B, and SC–4A were located approximately 

midway between upgradient wells SC–1A and SC–1B and 

downgradient wells SC–5A and SC–5B. 

Figure 6. Well-numbering system in New Mexico.

Well Location, Installation, Construction, and Development 

6 m i le s

Well 29N.14E.28.441

1 4

N

2 9

Well
During Phase II, well SC–6A was installed west of the 

middle cluster of wells in the Straight Creek drainage to monitor ground-water conditions where results of a geophysical 

cross-section survey indicated that the debris-flow deposits 

were the thickest. Wells SC–7A and SC–8A were installed in 

the Red River alluvial deposits west of Straight Creek in an 

area postulated to be a mixing zone of Straight Creek and Red 

River ground water (fig. 3). Well SC–7A was screened across 

an interval of approximately 90 ft to compare water chemistry 

at selected depths within this postulated mixing zone. Comparison of water chemistry in samples from wells SC–7A and 

SC–8A is anticipated to aid in characterizing the mixing of 

acidic water from the debris fan near the mouth of Straight 

Creek with near-neutral pH water in the Red River alluvium. 

Well SC–9A was installed on the north bank of the Red River 

to complete the series of wells in the Straight Creek drainage 

basin and to monitor conditions at the ground-water/Red River 

interface. 

The Hottentot, Hansen, and La Bobita wells were 

installed in debris-flow deposits to monitor ground-water conditions at these analog sites. The Capulin Canyon wells were 

installed to monitor ground-water conditions at an analog site 

without debris-flow deposits.

Phase III wells were installed in unconsolidated material along an approximately 1-mi reach of the Red River west 

of Elephant Rock campground (fig. 1). These wells were 

installed to examine the interaction of the Red River and water 

in the Red River alluvium.

Well locations and altitudes, construction information, 

and initial ground-water-level measurements for Phase II and 

Phase III wells are listed in table 1. Latitudes, longitudes, and 

altitudes of Phase II wells were determined by Molycorp using 

a Trimble 5800 Real Time Kinematic RoverTM with a Trimble 

5700 Global Positioning System (GPS) Total StationTM base; 

accuracy of the system is ± 0.016 ft horizontally and ± 0.1 ft 

vertically (B.M. Walker, Molycorp, written commun(s)., 

2003). 

Latitudes and longitudes for Phase III wells were 

determined using a Garmin eTrex® 12-parallel-channel GPS 

receiver; horizontal accuracy is ± 20 ft. The altitude of well 

AWWT–1 was estimated by using a hand-held site level and 

the altitude of the previously surveyed SC–7A well. The altitude of well AWWT–2 was determined from a USGS 

71⁄2-minute (1:24,000-scale) topographic map. Altitudes of 

Phase III wells 1, 2–1, 2–2, and 3 were determined by a level 

survey from the previously surveyed Phase II La Bobita well 

(fig. 4). Altitudes of Phase III wells—4–1D, 4–SD, 4–2D, 

4–2S, 4–3D, and 4–3S—were determined by estimation of the 

altitude of well 4–1D from a USGS 71⁄2-minute topographic 

map and a level survey from well 4–1D to the other five wells.

Phase II Drilled Wells

WDC Drilling Company (formerly THF Drilling Company) of Phoenix, Arizona, under direction of Souder, Miller 

and Associates (SMA) hydrogeologists and USGS hydrologists, drilled, constructed, and developed 8 of the 11 Phase 

II observation wells. These wells included the Hottentot 

well; Straight Creek wells SC–6A, SC–7A, and SC–8A; the 

Hansen well; the La Bobita well; and Capulin Canyon wells 

CC–1B and CC–2B. The locations of these wells are shown 

in figures 2–5, and information describing well location and 

construction is listed in table 1.

All eight wells were drilled using an Ingersoll Rand 

TH75E air-rotary/hammer rig equipped with a Stratex® 

casing-advance system and an onboard Ingersoll Rand air 

compressor (an auxiliary compressor provided additional 

air capacity as needed). Boreholes were drilled using a 9-in. 

diameter button bit. Boreholes were advanced to total well 

depth using the Stratex® system to temporarily case the holes 

to ensure that the holes did not collapse. The temporary casing 

was cleaned using phosphate-free detergent and tapwater prior 

to drilling each well.

Each of the eight wells was constructed using new, 

flush-threaded, 4-in. diameter, schedule-80 polyvinyl chloride 

(PVC) casing and factory-cut, 0.010-in. slot-size PVC screen 

with threaded end cap. The annulus of each well was filled 

with 10/20 silica sand from the bottom of the hole to a minimum of 2.5 ft above the top of the screen. A hydrated bentonite-pellet seal, typically from 4 to 8 ft thick, was installed 

above the 10/20 silica sand, and hydrated bentonite chips were 

installed above the seal to the land surface.

Each of the eight wells was developed until specific 

conductance, pH, and temperature stabilized. Stabilization criteria were: specific conductance, ±10 percent; pH, 

±0.1 standard unit; and temperature, ±0.5o C. Each well was 

initially developed by mechanical surging for a minimum of 

20 minutes. Wells CC–1B and CC–2B were further developed 

by additional surging and subsequent pumping. Wells SC–6A, 

SC–8A, and the Hottentot, Hansen, and La Bobita wells were 

further developed by mechanical surging and subsequent bailing; wells SC–6A, SC–8A, and the Hottentot well were further 

developed by pumping following bailing. Well SC–7A was 

further developed solely by pumping. 

Phase II Small-Diameter Wells

Phase II small-diameter wells were installed using a 

Geoprobe Model 6610-DT. The Geoprobe (a direct-push rig) 

uses hydraulic pressure and supplementary hammering to 

advance the drill point and drill rod. Wells CC–1A and CC–2A 

were installed in Capulin Canyon (fig. 5) next to the air-rotarydrilled wells CC–1B and CC–2B, respectively. Well SC–9A 

(fig. 3) was installed at the mouth of the Straight Creek drainage near the upstream end of the Elephant Rock campground 

(fig. 1). Prior to installing the SC–9A well casing, three smalldiameter, vertical holes were advanced to between 20 and 36 ft 

below land surface along the north bank of the Red River in 

an attempt to locate the water table. All three holes were dry. 

A fourth small-diameter hole (well SC–9A) was advanced 

10 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15
Table 1. Locations, altitudes, construction information, and initial water levels for phase II and III wells, Red River Valley, north-central New Mexico, 2002–04.

 [NA, not available or not applicable; NGVD 29, National Geodetic Vertical Datum of 1929] 

Well

(figs. 2–5)

U.S. Geological 

Survey site 

identifier

Well location

Latitude

(degrees, 

minutes, 

seconds)

Longitude

(degrees, 

minutes, 

seconds)

Landsurface 

altitude 

(feet above 

NGVD 29)

Date 

completed

(month/

day/year)

Bore-hole 

depth (feet 

below 

land 

surface)

Well 

depth 

(feet below land 

surface)

Screened 

interval 

(feet below 

land surface)

Date 

water 

level 

measured 

(month/

day/year)

Initial 

water 

level 

(feet below land 

surface)

Initial 

waterlevel altitude (feet 

above 

NGVD 29)

Phase II wells

Hottentot 364240105255001 29N.14E.34.211 36o42’40.43” 105o25’50.19” 8,790.79 10/30/02 118.0 115.5 105–115 02/05/03 98.72 8,692.07SC–6A1 364245105263901 29N.14E.33.221D 36o42’45.67” 105o26’39.33” 8,739.43 11/12/02 150.0 148.5 129–149 02/07/03 133.12 8,606.31SC–7A1 364228105264301 29N.14E.33.241 36o42’28.25” 105o26’43.04” 8,506.86 12/07/02 196.0 195.5 107–195 02/04/03 108.08 8,398.78SC–8A1 364225105264501 29N.14E.33.234 36o42’25.42” 105o26’45.66” 8,468.22 11/24/02 98.0 97.5 87–97 02/08/03 69.84 8,398.38SC–9A 364224105264401 29N.14E.33.234A 36o42’24.30” 105o26’43.30” 8,444.19 11/13/02 20.9 20.9 16.4–20.9 02/08/03 Dry DryHansen 364228105273201 29N.14E.33.131 36o42’28.17” 105o27’32.09” 8,569.53 11/07/02 120.0 109.5 99–109 02/05/03 104.68 8,464.85La Bobita 364204105282201 29N.14E.32.341 36o42’03.67” 105o28’22.29” 8,229.45 12/08/02 65.0 63.5 53–63 02/07/03 61.14 8,168.31CC–1A 364234105321301 29N.13E.34.214A 36o42’33.96” 105o32’13.24” 8,880.23 11/13/02 12.5 12.5 7.5–12.5 02/04/03 3.40 8,876.83CC–1B 364234105321302 29N.13E.34.214B 36o42’33.93” 105o32’13.08” 8,878.31 10/29/02 40.0 39.0 23.5–38.5 02/05/03 7.54 8,870.77CC–2A 364234105321303 29N.13E.34.232A 36o42’33.83” 105o32’12.53” 8,876.02 11/13/02 17.0 16.0 11.0–16.0 04/10/03 4.42 8,871.60CC–2B 364234105321201 29N.13E.34.232B 36o42’33.74” 105o32’12.45” 8,877.53 10/24/02 116.5 115.5 56.5 – 105.25 02/05/03 8.66 8,868.87

Phase III wells

Site 12 364159105282101 29N.14E.32.314 36o41’58.70” 105o28’20.89” 8,187.30 12/03/03 26.02 25.82 20.82–25.82 12/17/03 19.88 8,167.42Site 2–12 364203105281201 29N.14E.32.341 36o42’02.81” 105o28’12.40” 8,207.92 12/03/03 15.97 14.06 9.06–14.06 12/17/03 7.18 8,200.74Site 2–22 364203105281301 29N.14E.32.341A 36o42’03.46” 105o28’12.86” 8,207.94 12/03/03 14.37 13.12 8.12–13.12 12/17/03 8.29 8,199.65Site 32 364206105275401 29N.14E.32.432 36o42’05.80” 105o27’54.43” 8,255.54 12/03/03 9.21 9.21 4.21–9.21 12/17/03 3.61 8,251.93Site 4–1D2 364216105272201 29N.14E.33.312 36o42’16.27” 105o27’22.32” 8,398.00 12/04/03 39.50 36.67 31.67–36.67 12/18/03 7.10 8,390.90Site 4–1S2 364216105272202 29N.14E.33.312A 36o42’16.27” 105o27’22.32” 8,398.10 12/04/03 19.05 19.04 14.04–19.04 12/18/03 7.14 8,390.96Site 4–2D2 364218105272101 29N.14E.33.312B 36o42’18.14” 105o27’20.88” 8,401.95 12/04/03 38.10 38.10 33.10–38.10 12/18/03 10.05 8,391.90Site 4–2S2 364218105272102 29N.14E.33.312C 36o42’18.14” 105o27’20.88” 8,402.32 12/04/03 19.5 18.95 13.95–18.95 12/18/03 10.47 8,391.85Site 4–3D2 364219105271901 29N.14E.33.312D 36o42’18.83” 105o27’18.68” 8,397.86 12/04/03 38.52 38.49 33.49–38.49 12/17/03 11.06 8,386.80Site 4–3S2 364219105271902 29N.14E.33.312E 36o42’18.83” 105o27’18.68” 8,398.00 12/04/03 19.5 18.90 13.90–18.90 12/17/03 11.25 8,386.75

1 Latitude, longitude, and altitude data determined by Molycorp using a Trimble 5800 Real Time Kinematic Rover with Trimble 5700 Global Positioning System Total Station base; accuracy of the system is 

±0.016 foot horizontally and ± 0.1 foot vertically. All other information for Straight Creek wells was measured at time of drilling and well installation.

2 Latitude and longitude determined using a Garmin eTrex 12-parallel-channel GPS receiver; horizontal accuracy is ±20 ft. 

Well Location, Installation, Construction, and Development 11
under the Red River at an angle of 21.5 degrees from vertical 

to a total angular depth of 22.5 ft. The vertical depth below 

land surface of this well is 20.9 ft and the bottom of the well 

is about 1.3 ft beyond the bank of the river. Well SC–9A also 

was dry at the time of installation.

Each of the Phase II small-diameter wells (CC–1A, 

CC–2A, and SC–9A) was completed by installing a 5-ft long, 

1-in. diameter schedule 40 PVC factory-cut, 0.010-in. slot-size 

screen with a bottom cap at the total depth of the hole and 1-

in. diameter schedule 40 PVC casing above the slotted-screen 

section to approximately 2 ft above land surface. The annulus 

of each well was filled with 10/20 silica sand from total depth 

to within about 5 ft of land surface, above which the annulus 

was filled with 3/8-in. bentonite pellets to the land surface. 

Wells CC–1A and CC–2A were surged for 15 and 

50 minutes, respectively, and then purged until dry using a 

bailer or a peristaltic pump and dedicated tubing, after which 

the wells were allowed to recover. This purging and recovery 

sequence was conducted three times in each well. Well SC–9A 

was not developed because it was dry at the time of 

installation. 

Phase III Small-Diameter Wells

Several facts, including well SC–9A being dry at completion, results of two synoptic tracer studies (McCleskey and 

others, 2003), and results of geomorphologic investigations 

(Kirk Vincent, USGS, written commun., 2005), suggested that 

from Straight Creek to about 1,500 ft upstream from Hansen 

Creek, surface water in the Red River and the underlying 

ground water in the Red River alluvium are hydraulically 

disconnected. In this area, ground water originating in debrisflow deposits likely flows into the Red River alluvial aquifer 

and remains in the subsurface hydraulically disconnected from 

the Red River. Ten small-diameter observation wells were 

installed along approximately a 1-mi reach of the Red River 

west of Elephant Rock campground to measure water levels 

to characterize ground-water flow along this reach of the Red 

River (fig. 4).

Ten Phase III wells were completed by installing a 5-ft 

long, 1-in. diameter schedule 40 PVC factory-cut, 0.010-in. 

slot-size screen with a bottom cap at total depth of the hole 

and 1-in. diameter schedule 40 PVC casing above the slottedscreen section to approximately 2 ft above land surface. The 

annulus of each well was filled with 10/20 silica sand from 

total depth to within about 5 ft of land surface, above which 

the annulus was filled with 3/8-in. bentonite pellets to the land 

surface. The wells were developed by pumping a minimum of 

three casing volumes of water from each well using a peristaltic pump and dedicated tubing. Specific conductance, pH, temperature, and turbidity were monitored during development.

Lithologic and Geophysical Well 

Logging

Lithologic logs were recorded for all eight Phase II airrotary-drilled wells, and borehole geophysical logging was 

conducted in Phase II wells SC–6A, SC–7A, and SC–8A. 

Well-completion diagrams and lithologic logs for the Hottentot, Hansen, La Bobita, and Capulin (CC–1B and CC–2B) 

wells are shown in figure 7, and well-completion diagrams, 

lithologic logs, and geophysical logs for wells SC–6A, 

SC–7A, and SC–8A are shown in figure 8. 

Lithologic Logging

Lithologic logs were constructed from examination of 

borehole cuttings from the Hottentot, Hansen, La Bobita, 

and Capulin (CC–1B and CC–2B) wells, and wells SC–6A, 

SC–7A, and SC–8A (Souder, Miller, and Associates, 2003). 

Borehole cuttings were collected from all eight wells from 

land surface to total depth. Cuttings were collected at 5-ft 

intervals from sampling cyclones and stored in 5-gal (gallon) plastic containers. Representative samples from each 5-ft 

interval were examined in the field using a hand lens (Souder, 

Miller, and Associates, 2003). The level of detail in field logging of samples was dictated by the condition of the sample 

(wet or dry, fine or coarse) and the time available for inspection. Ludington and others (2005) conducted detailed analyses 

of these samples. 

Geophysical Logging

Natural gamma, induction, and single-detector neutron 

geophysical logging was conducted in wells SC–6A, SC–7A, 

and SC–8A (figs. 8A, 8B, and 8C) during February 2003, 

following well completion and development. Logging and 

log interpretation was conducted using information regarding 

geophysical logging applications in ground-water investigations by Keys (1986, 1990), Jorgensen (1991), Paillet and 

Crowder (1996), and Hearst and others (2000). In completed 

wells SC–6A, SC–7A, and SC–8A, the conditions in the 

annulus between the 4-in. PVC casing and the 9-in. diameter 

bore holes at the time of logging were not representative of the 

undisturbed aquifer material beyond the borehole, and these 

disturbed conditions substantially limited interpretations of 

these logs. 

Two primary quality-control measures were used during the collection of geophysical log data. First, an accurate 

depth scale was ensured by verifying that the depth indicator 

on the log recorded a value within about 0.8 in. of zero when 

the probe was returned to the pre-logging measurement reference point. Second, nuclear logging was repeated in selected 

sections of the wells to verify the repeatability of the initial 

logging results.

12 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15
Figure 7A. Well-completion data and lithologic log for Hottentot well (modified from Souder, Miller, and Associates, 2003).

Lithologic and Geophysical Well Logging 13

6-INCH THREADED CAP

BOTTOM OF SCREEN: 115 FEET 

BELOW LAND SURFACE

TOP OF BENTONITE

PLUG: 96 FEET

BELOW LAND SURFACE

BELOW LAND SURFACE

0.010-INCH SLOT SCREEN

TOP OF SCREEN: 105 FEET

100 FEET BELOW LAND SURFACE

10/20 SILICA SAND

TOP OF FILTER PACK

TOTAL DEPTH 118 FEET

PVC CAP

LOCKING METAL SHROUD

8 5/8-INCH OUTSIDE DIAMETER,

5 FEET LONG, 3-FOOT STICK-UP

ABOVE LAND SURFACE

3 FEET x 3 FEET x 1

FOOT CONCRETE PAD

3/8-INCH HYDRATED

BENTONITE CHIPS

WELL-COMPLETION DATA 

4-INCH DIAMETER

SCHEDULE 80 PVC CASING

9-INCH DIAMETER

BOREHOLE

LITHOLOGIC LOG 

(A) Hottentot well

DEPTH TO WATER 98 FEET

BELOW LAND SURFACE

MEASURED NOVEMBER 7, 2002 100

110

120

90

80

60

70

50

30

40

20

10

0

DEPTH BELOW LAND SURFACE, IN FEET 

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29 

8,781

8,771

8,761

8,751

8,741

8,731

8,721

8,711

8,701

8,691

8,681

8,671

Sand with gravel and clay. 60 percent coarse sand,

25 percent gravel, 15 percent clay. Light brown to 

tan. Moist. Weathered rhyolitic fragments with 

quartz phenocrysts. 

Sand with gravel and clay. 55 percent coarse 

sand, 40 percent gravel, 5 percent clay. Light 

brown to tan. Moist. Weathered gray rhyolite and 

quartz latite fragments. 

Gravel with sand and silt. 60 percent gravel, 35

percent medium-grained sand, 5 percent silt. Light 

brown to tan. Dry. More argillized than above.

Some fluorite. 

Gravel with sand and silt. 55 percent gravel, 40

percent coarse sand, 5 percent silt. Light brown to

tan. Dry. Weathered andesite and rhyolitic 

fragments with quartz phenocrysts. Sericitization.

Minor pyrite.

Sand with gravel and silt. 60 percent coarse sand, 

35 percent gravel, 5 percent silt. Light brown to

tan. Dry. Lithology same as above with pieces of

microcrystalline quartz containing minor pyrite.

Sericitization.

Sand with gravel and silt. 55 percent coarse sand, 40

percent gravel, 5 percent silt. Light brown to tan. Dry. 

Rhyolite and quartz fragments. Limonite staining. 

Sand with gravel, silt, and clay. 45 percent coarse

sand, 35 percent gravel, 15 percent silt, 5 percent 

clay. Light brown to tan. Moist. Weathered rhyolite 

porphyry. Limonite staining and quartz flooding. 

Sand with gravel, silt, and clay. 35 percent 

coarse sand, 30 percent gravel, 15 percent silt, 

20 percent clay. Light brown. Moist. Fragments 

of rhyolite porphyry. 

Sand with gravel, silt, and clay. 35 percent coarse

sand, 30 percent gravel, 15 percent silt, 20

percent clay. Light brown to tan. Moist.

Fragments of rhyolite porphyry. Quartz flooding.

Conchoidal fractures. 

Sand, gravel, silt, and clay. 35 percent 

medium-grained sand, 30 percent gravel, 20

percent clay, 15 percent silt. Light brown to tan.

Very moist. Rhyolite porphyry fragments.

Sand with gravel, silt, and clay. 35 percent 

medium grained sand, 30 percent gravel, 20

percent clay, 15 percent silt. Light brown. Wet. 

Rhyolite porphyry fragments.

Sand with gravel, silt, and clay. 35 percent 

medium-grained sand, 30 percent gravel, 20

percent clay, 15 percent silt. Light brown. Wet. 

Rhyolite porphyry fragments.

8,791
Figure 7B. Well-completion data and lithologic log for Hansen well (modified from Souder, Miller, and Associates, 2003).

14 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

PVC CAP

3 x 3 X 1-FOOT 

CONCRETE PAD

WELL-COMPLETION DATA LITHOLOGIC LOG 

TOTAL DEPTH 120 FEET

LOCKING METAL SHROUD

8 5/8-INCH OUTSIDE DIAMETER,

5 FEET LONG, 3-FOOT STICK-UP

ABOVE LAND SURFACE

 DEPTH TO WATER 103 FEET

 BELOW LAND SURFACE

MEASURED NOVEMBER 10, 2002

(B) Hansen well

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29 

DEPTH BELOW LAND SURFACE, IN FEET 

Gravel with sand and silt. 55 percent 

coarse sand, 40 percent gravel, 5 percent 

clay. Light brown. Dry. Weathered gray

rhyolite porphyry along with some ash-flow

tuff and highly argillized white fragments. 

Limonite staining. Trace pyrite. 

Sand with gravel and silt. 65 percent fine 

to coarse sand, 25 percent gravel, 10

percent silt. Light brown. Dry. Gray

rhyolite, ash-flow tuff, fine-grained green 

fragments with trace pyrite. Limonite 

staining. Fragments of crystalized tuff. 

Sand with gravel and silt. 70 percent fine 

to coarse sand, 15 percent gravel, 15

percent silt. Light brown tan. Dry. Gray 

andesite, rhyolite, ash-flow tuff and highly 

argillized white fragments. Sericitization.

Limonite staining. 

Sand with gravel and silt. 70 percent fine to 

coarse sand, 15 percent gravel, 15 percent 

silt. Red brown. Dry. Gray rhyolite, ash-flow

tuff, fine-grained green fragments with 

trace pyrite. Sericitization. Limonite 

staining. 

Sand with silt and gravel. 60 percent fine 

to coarse sand, 20 percent silt, 20

percent gravel. Light brown. Slightly 

moist. Ash-flow tuff, dark and light 

rhyolitic fragments with pyrite and other 

highly weathered fragments. Limonite 

staining. 

Same as above. Increased sericitization of 

feldspars. 

Sand with silt and gravel. 60 percent fine to 

coarse sand, 20 percent silt, 20 percent 

gravel. Light brown. Slightly moist. Rhyolite 

and andesite fragments. Limonite staining. 

Some pyrite. 

Same as above. Intense sericitization and 

argillization. 

Sand with gravel and silt. 60 percent fine 

to coarse sand, 20 percent gravel, 20

percent silt. Light brown. Slightly moist. 

Weathered rhyolite and rhyolitic tuff, light 

gray fine-grained fragments. Minor pyrite. 

Bedrock at 110 feet. Consolidated gray

dacite. 0.2 to 0.4 percent pyrite. Feldspars,

sericitized and argillized. 

90 

80 

60 

70 

50 

30 

40 

20 

10 

100 

110 

120 

0 

3/8-INCH HYDRATED

BENTONITE CHIPS

4-INCH DIAMETER

SCHEDULE 80 PVC CASING

9-INCH DIAMETER

BOREHOLE

BENTONITE CHIP SEAL

BOTTOM OF SCREEN: 109 FEET 

6-INCH THREADED CAP

BELOW LAND SURFACE

95 FEET BELOW LAND SURFACE

10/20 SILICA SAND

TOP OF BENTONITE

PLUG: 87 FEET

BELOW LAND SURFACE

BELOW LAND SURFACE

0.010-INCH SLOT SCREEN

TOP OF SCREEN: 99 FEET

TOP OF FILTER PACK

8,570

8,560

8,550

8,540

8,530

8,520

8,510

8,500

8,490

8,480

8,470

8,460

8,450
Natural gamma logs are used to estimate the proportion 

of clay minerals and (or) the proportion of unweathered mineral grains in the aquifer. The log measures the gamma activity 

produced by naturally occurring isotopes of uranium, potassium, and thorium in the formation beyond the borehole and, 

therefore, indicates variations in the lithology of aquifer materials. Log units are counts per second (cps). Well-casing and 

borehole fluid typically attenuate the flux of gamma particles 

from the undisturbed geologic material beyond the borehole 

to the detector in the logging tool resulting in reduced gamma 

counts. To minimize this attenuation, the log is run with the 

probe decentralized so that the probe is free to move within 

and lie against the side of the borehole or well that is not 

precisely plumb. 

The induction log shows the bulk electrical resistivity of 

the aquifer material and the fluid in the aquifer material’s pore 

spaces. Log units are ohm-meters. Resistivity values can vary 

depending on the electrical properties of the aquifer material, 

with the degree of saturation of the aquifer material, and with 

Figure 7C. Well-completion data and lithologic log for La Bobita well (modified from Souder, Miller, and Associates, 2003).

Lithologic and Geophysical Well Logging 15

PVC CAP

WELL-COMPLETION DATA LITHOLOGIC LOG

LOCKING METAL SHROUD

8 5/8-INCH OUTSIDE DIAMETER,

5 FEET LONG, 3-FOOT STICK-UP

ABOVE LAND SURFACE

3 FEET x 3 FEET x 1 FOOT CONCRETE PAD

4-INCH DIAMETER

SCHEDULE 80 PVC CASING

9-INCH DIAMETER

BOREHOLE

(C) La Bobita well

8,229

20

10

0

Sand with gravel. 60 percent coarse-grained sand, 40

percent gravel. Dark gray. Dry. Dark gray fine-grained 

biotized andesite and dacite. Hard drilling. Homogeneous 

and angular. Possibly cobbles ground into sand by drilling.

Sand with gravel. 60 percent coarse- to fine-grained sand, 40

percent gravel. Dark gray. Dry. Dark gray fine-grained 

biotized andesite and dacite. Possibly mafic dikes. Trace 

pyrite.

3/8-INCH HYDRATED 

BENTONITE CHIPS

TOP OF BENTONITE

PLUG: 34 FEET

BELOW LAND SURFACE

40 FEET BELOW LAND SURFACE

10/20 SILICA SAND

TOP OF FILTER PACK

DEPTH TO WATER 60.4 FEET BELOW LAND 

SURFACE MEASURED 

DECEMBER 9, 2002

8,219

8,209

8,199

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

DEPTH BELOW LAND SURFACE, IN FEET

50

30

40

Gravel with sand. 70 percent gravel, 30 percent coarse- to 

fine-grained sand. Dark gray. Dry. Dark gray fine-grained 

biotized andesite and dacite.

Gravel with sand and clay. 55 percent gravel, 40 percent 

coarse to fine sand, 5 percent clay. Dark gray. Dry. Dark

gray fine-grained biotized andesite and dacite. Trace 

pyrite.

TOTAL DEPTH 65 FEET 6-INCH THREADED CAP

BOTTOM OF SCREEN: 63 FEET 

BELOW LAND SURFACE

BELOW LAND SURFACE

0.010-INCH SLOT SCREEN

TOP OF SCREEN: 53 FEET

8,189

8,179

8,159

60 8,169

70

Bedrock at 55 feet. Dark gray. Chloritized/biotized dacite 

to andesite. Some porphyritic fragments. Trace pyrite.

Gravel with sand. 55 percent gravel, 45 percent coarse- to 

fine-grained sand. Dark gray. Dry. Dark gray fine-grained 

biotized andesite and dacite. No pyrite.
the electrical properties of the water filling pore spaces in the 

aquifer material.

Single-detector neutron logs provide an estimate of the 

degree of saturation of aquifer materials and, below the water 

table, the porosity of these materials. The single-detector 

neutron log generates a flux of neutrons and measures the 

rate at which those neutrons are scattered back to the detector. 

Neutrons generated by the logging tool are absorbed through 

collision with hydrogen atoms so the count rate is inversely 

proportional to the total amount of water within a radius of 

approximately 10 in. of the logging tool. To minimize the 

effects of casing and annulus materials on logging results in 

completed wells, the single-detector neutron log is run with 

the probe decentralized and free to move within and lie against 

the side of a casing that is not precisely plumb. Log units are 

counts per second. Typically, the response of the single-detector neutron log to fully saturated materials is less than about 

2,000 cps, the response to partially saturated materials is about 

2,000 to 3,500 cps, and the response to relatively dry materials is more than about 3,500 cps. Neutron logs in saturated 

formations respond to the total of effective (drainable) and 

noneffective (nondrainable and often containing geochemically bound water) porosity. 

In completed wells SC–6A, SC–7A, and SC–8A, the conditions in the annulus between the 4-in. PVC casing and the 

9-in. diameter boreholes inside the casing and the annulus at 

the time of logging were not representative of the undisturbed 

aquifer material beyond the borehole, and these disturbed 

conditions substantially affected the neutron counts in the 

saturated zone. Above the water table, however, the results 

of neutron logging provided some measure of the degree of 

saturation of the aquifer materials.

In well SC–6A, the gamma count decreased, the resistivity increased, and the neutron count was unusually high 

(greater than 4,000 cps) between top of the sand pack in the 

annulus at 122 ft and the top of the saturated zone, about 

133 ft at the time logging was conducted (fig. 8A). The unusually high neutron count indicates that the deposits about 11 ft 

above the water table were dry. The lithologic log, however, 

indicates that the cuttings retrieved from this interval were wet 

(fig. 8A). This inconsistency between the lithologic log and the 

geophysical log interpretation indicates that the change in the 

Figure 7D. Well-completion data and lithologic log for CC–1B well (modified from Souder, Miller, and Associates, 2003).

16  Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

WELL-COMPLETION DATA LITHOLOGIC LOG

(D) CC–1B well

LOCKING METAL SHROUD 8 5/8-INCH OUTSIDE DIAMETER,

5 FEET LONG, 3-FOOT STICK-UP

ABOVE LAND SURFACE

3 FEET x 3 FEET x 1 FOOT CONCRETE PAD

3/8-INCH HYDRATED

BENTONITE CHIPS

4-INCH DIAMETER

SCHEDULE 80 PVC CASING

10

0

DEPTH BELOW LAND SURFACE, IN FEET

PVC CAP

9-INCH DIAMETER

BOREHOLE

TOP OF BENTONITE

PLUG: 20 FEET

BELOW LAND SURFACE

BELOW LAND SURFACE

0.010-INCH SLOT SCREEN

TOP OF SCREEN: 23.5 FEET

21 FEET BELOW LAND SURFACE

10/20 SILICA SAND

TOP OF FILTER PACK

DEPTH TO WATER 10 FEET BELOW LAND 

SURFACE MEASURED 

OCTOBER 30, 2002

30

20

TOTAL DEPTH 40 FEET

6-INCH THREADED CAP

BOTTOM OF SCREEN: 38.5 FEET 

BELOW LAND SURFACE

DEPTH TO WATER 

36 FEET BELOW LAND 

SURFACE MEASURED 

OCTOBER 29, 2002 40

8,878

8,858

8,868

8,838

8,848

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

Gravel with sand. 60 percent gravel and 40 percent 

coarse sand. Gray dacite fragments. Argillized 

feldspars. Dark brown. Dry.

Gravel with sand and silt. 50 percent gravel, 40

percent coarse sand, 10 percent silt. Dacite 

fragments. Gray. Dry.

Sand, gravel, silt, and clay. 40 percent sand, 20

percent gravel, 20 percent silt, 20 percent clay. Gray

dacite with clay. Likely fractured top of bedrock with 

clay-filled features. Trace pyrite.

Sand, gravel, silt and clay. 40 percent sand, 20

percent gravel, 20 percent silt, 20 percent clay.

Gray dacite with clay. Likely fractured top of 

bedrock with clay-filled features. Trace pyrite.

Some dacite porphyry. 
Figure 7E. Well-completion data and lithologic log for CC–2B well (modified from Souder, Miller, and Associates, 2003).

Hydraulic Testing to Determine Aquifer Characteristics 17

WELL-COMPLETION DATA LITHOLOGIC LOG

(E) CC–2B well

LOCKING METAL SHROUD

8 5/8-INCH OUTSIDE DIAMETER,

5 FEET LONG, 3-FOOT STICK-UP

ABOVE LAND SURFACE

3 FEET x 3 FEET x 1 FOOT CONCRETE PAD

3/8-INCH HYDRATED

BENTONITE CHIPS

4-INCH DIAMETER

SCHEDULE 80 PVC CASING

9-INCH DIAMETER

BOREHOLE

DEPTH TO WATER 17 FEET BELOW LAND

SURFACE MEASURED

OCTOBER 30, 2002

No sample

8,878

8,868

30

20

10

0

Clay with sand, gravel and silt. Gravel size 

composed of assorted rock fragments, 

including rhyolitic to andesitic rocks.

PVC CAP

TOP OF BENTONITE

PLUG: 40 FEET

BELOW LAND SURFACE

BELOW LAND SURFACE

0.010-INCH SLOT SCREEN

TOP OF SCREEN: 56.5 FEET

50 FEET BELOW LAND SURFACE

10/20 SILICA SAND

TOP OF FILTER PACK

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

DEPTH BELOW LAND SURFACE, IN FEET

8,858

8,838

8,848

50 8,828

40

Bedrock at 19-20 feet, gray dacite to andesite. 

Feldspars sericitized and argillized. Trace of 

minor pyrite (less than 0.1 percent). 

Purple material with some clay. Likely an ash 

flow, or perhaps sheared intermediate 

volcanics. Iron-oxide rich.

BOTTOM OF SCREEN: 105.25 FEET 

BELOW LAND SURFACE

DEPTH TO WATER 97 FEET BELOW LAND

SURFACE MEASURED

OCTOBER 26, 2002

8,818

8,808

8,798

8,768

8,778

90 8,788

80

60

70

100

110

Bedrock, gray andesite. Feldspars sericitized.

No pyrite.

Andesite ash-flow with trace pyrite and iron 

oxide.

Bedrock, gray andesitic ash-flow. Mafics

chloritized. Some andesite inclusions.

4-INCH PVC CASING TO 115 FEET

BELOW LAND SURFACE

TOTAL DEPTH 116.5 FEET 6-INCH THREADED CAP 120 8,758
Figure 8A. Well-completion data, lithologic log, and geophysical log for SC–6A well. Well-completion data and 

lithologic log modified from Souder, Miller, and Associates (2003).

18  Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

WELL-COMPLETION DATA LITHOLOGIC LOG

LOCKING METAL SHROUD 8 5/8-INCH OUTSIDE DIAMETER,

5 FEET LONG, 3-FOOT STICK-UP

ABOVE LAND SURFACE

(A) SC–6A well

3 FEET x 3 FEET x 1

FOOT CONCRETE PAD

PVC CAP

3/8-INCH HYDRATED

BENTONITE CHIPS

4-INCH DIAMETER

SCHEDULE 80 PVC CASING

9-INCH DIAMETER

BOREHOLE

30

20

10

0

TOP OF BENTONITE

PLUG: 119 FEET

BELOW LAND SURFACE

TOP OF SCREEN: 128 FEET

122 FEET BELOW LAND SURFACE

10/20 SILICA SAND

TOP OF FILTER PACK

DEPTH BELOW LAND SURFACE, IN FEET

90

80

60

70

50

40

100

110

120

130

6-INCH THREADED CAP TOTAL DEPTH 150 FEET

BOTTOM OF SCREEN: 148 FEET 

BELOW LAND SURFACE

BELOW LAND SURFACE

0.010-INCH SLOT SCREEN

DEPTH TO WATER 133 FEET BELOW LAND 

SURFACE MEASURED 

NOVEMBER 13, 2002

150

140

8,589

8,599

Sand with gravel and clay. 55 percent coarse 

sand, 40 percent gravel, 5 percent clay.

Rhyolite, highly weathered and argillized 

fragments. Quartz veins. Trace pyrite. Quartz 

flooding. Limonite staining.

Sand with gravel and clay. 55 percent coarse 

sand, 40 percent gravel, 5 percent clay. Red to 

brown. Moist. Rhyolite fragments. Quartz veins.

Trace pyrite. Some ferricrete. Quartz flooding. 

Limonite staining.

Sand with gravel, silt and clay. 50 percent 

coarse sand, 30 percent gravel, 10 percent silt, 

10 percent clay. Light brown to tan. Wet. Highly 

weathered quartz and rhyolite porphyry 

fragments. Limonite staining. Quartz-sericitepyrite alteration.

Sand with gravel and clay. 55 percent coarse 

sand, 40 percent gravel, 5 percent clay. Light 

tan to brown. Wet. Rhyolite fragments. Trace 

pyrite. Fine-grained fragments with quartz 

and ferricrete.

Same as above. In addition, andesite 

fragments with pyrite, weathered rhyolitic, 

and quartz fragments. Limonite staining.

Sand with gravel, silt, and clay. 35 percent fine 

sand, 25 percent gravel, 20 percent silt, 20

percent clay. Lithologies and minerals same as 

above.

8,679

8,629

8,639

8,649

8,659

8,669

8,619

8,609

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

Rhyolite, dacite/andesite fragments.

Gravel with sand and clay. 55 percent gravel,

40 percent coarse- to medium-grained sand, 5 

percent clay. Light tan to brown. Moist.

Rhyolite, quartz, and fine-grained fragments 

with pyrite. Argillized and weathered 

fragments. Limonite staining.

Same as above. In addition, rhyolite, andesite 

and fine-grained fragments with pyrite and 

epidote. Weathered fragments. Limonite 

staining. Quartz flooding.

8,739

8,719

8,729

8,709

8,699

8,689

Gravel with sand. 65 percent coarse- to 

medium-grained sand, 35 percent gravel. Light 

brown. Dry. Rhyolite, quartz latite, highly

weathered and argillized fragments. Trace pyrite

(less than 0.1 percent). Limonite staining. 

Feldspars altered.

Gravel with sand. 55 percent gravel, 45 percent 

coarse- to medium-grained sand. Light brown to 

tan. Dry. Rhyolite fragments. Sericitized, quartz 

flooding. Some quartz veinlets.

Fragments of welded tuff. 0.2 to 0.4 percent 

pyrite.
Figure 8A. Well-completion data, lithologic log, and geophysical log for SC–6A well.—Continued 

Well-completion data and lithologic log modified from Souder, Miller, and Associates (2003).

Hydraulic Testing to Determine Aquifer Characteristics 19

80 160 240 15 30 45 1,000 3,000 5,000

(A) SC–6A well

GAMMA ACTIVITY,

IN COUNTS PER SECOND

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

INDUCTION RESISTIVITY,

IN OHM-METERS

NEUTRON ACTIVITY,

IN COUNTS PER SECOND

DEPTH BELOW LAND SURFACE, IN FEET

8,719

8,729

8,709

8,699

8,679

8,689

8,629

8,639

8,649

8,659

8,669

8,619

8,589

8,599

8,609

8,739

90

80

60

70

50

30

40

20

10

100

110

120

130

150

140

0
Figure 8B. Well-completion data, lithologic log, and geophysical logs for SC–7A well.—Continued 

Well-completion data and lithologic log modified from Souder, Miller, and Associates (2003).

20 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

PVC CAP

WELL-COMPLETION DATA LITHOLOGIC LOG

LOCKING METAL SHROUD

8 5/8-INCH OUTSIDE DIAMETER,

5 FEET LONG, 3-FOOT STICK-UP

ABOVE LAND SURFACE

3 FEET x 3 FEET x 1

FOOT CONCRETE PAD

10

0 8,507

8,497

8,487

8,477

8,467

8,457

8,437

8,447

(B) SC–7A well

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

Gravel with sand. 55 percent gravel, 45 percent medium- to 

coarse-grained sand. Light brown. Dry. Ash-flow tuff, rhyolite,

and latite porphyry fragments. Quartz veins. Minor pyrite. 

Limonite staining.

Sand with gravel. 55 percent coarse- to medium-grained

sand, 45 percent gravel. Light brown. Dry. Rhyolite 

porphyry, andesite with pyrite, weathered and argillized

fragments, and fine-grained fragments with pyrite. 

Limonite staining. Quartz-sericite-pyrite alteration.

Sand with gravel. 55 percent coarse- to medium-grained

sand, 45 percent gravel. Light brown. Dry. Rhyolite 

fragments with up to 0.5 percent pyrite. Ash-flow tuff and 

fine-grained quartz-rich fragments. Limonite staining. 

Sand with gravel. 65 percent medium-grained sand, 35 

percent gravel. Light brown. Dry. Highly weathered with

pyrite fragments. Rhyolite fragments with quartz

phenocrysts and quartz veins. Limonite staining.

Sand with gravel. 70 percent coarse- to 

medium-grained sand, 30 percent gravel. Light brown.

Dry. Lithologies same as above.

Sand with gravel. 70 percent coarse- to medium-grained sand, 

30 percent gravel. Light brown. Dry. Rhyolite, ash-flow tuff, and 

fine-grained fragments. Up to 0.2 percent pyrite. Weathered 

fragments. Limonite staining.

Sand with gravel. 55 percent coarse- to medium-grained

sand, 45 percent gravel. Light brown. Dry. Fine-grained

fragments of rhyolite. Abundant pyrite. Highly weathered and 

argillized fragments. Limonite staining.

3/8-INCH HYDRATED

BENTONITE CHIPS

4-INCH DIAMETER

SCHEDULE 80 PVC CASING

9-INCH DIAMETER

BOREHOLE

70

60

50

40

30

20

DEPTH BELOW LAND SURFACE, IN FEET
Figure 8B. Well-completion data, lithologic log, and geophysical logs for SC–7A well.—Continued 

Well-completion data and lithologic log modified from Souder, Miller, and Associates (2003).

Hydraulic Testing to Determine Aquifer Characteristics 21

50

0

60

70

40

30

20

10

40 140 240 20 40 60 1,000 2,000 3,000

8,507

8,497

8,487

8,477

8,467

8,457

8,437

8,447

GAMMA ACTIVITY,

IN COUNTS PER SECOND

INDUCTION RESISTIVITY,

IN OHM-METERS

NEUTRON ACTIVITY,

IN COUNTS PER SECOND

(B) SC–7A well

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

DEPTH BELOW LAND SURFACE, IN FEET
Figure 8B. Well-completion data, lithologic log, and geophysical logs for SC–7A well.—Continued 

Well-completion data and lithologic log modified from Souder, Miller, and Associates (2003).

22 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

WELL-COMPLETION DATA LITHOLOGIC LOG

DEPTH TO WATER 

109 FEET BELOW LAND 

SURFACE MEASURED 

DECEMBER 7, 2002

8,437

8,407

8,417

8,427

8,377

8,387

8,397

8,367

(B) SC–7A well—Continued

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

Sand with gravel. 55 percent coarse to medium sand, 45

percent gravel. Light brown. Slightly moist. Rhyolite fragments, 

some with quartz veinlets. 

Sand with gravel. 90 percent coarse to medium sand, 10

percent gravel. Light brown. Slightly moist. Rhyolite fragments. 

Quartz veinlets. 

Sand with gravel and silt. 75 percent coarse- to fine-grained sand,

20 percent gravel, 5 percent silt. Light brown. Slightly moist. 

Rhyolite fragments with fine-grained weathered fragments.

Limonite staining.

Sand with gravel and silt. 70 percent coarse- to fine-grained 

sand, 20 percent gravel, 10 percent silt. Light brown. Slightly 

moist. Rhyolite fragments with fine-grained weathered

fragments. Limonite staining. 

Sand with gravel and silt. 70 percent coarse- to fine-grained 

sand, 20 percent gravel, 10 percent silt. Light brown. Slightly 

moist. Rhyolite fragments with fine-grained weathered

fragments.

Gray dacite and dacite porphyry boulder with pyrite.

Sand with gravel and silt. 60 percent coarse- to fine-grained 

sand, 20 percent gravel, 20 percent silt. Light brown. Moist. 

Water blows out when drilling. Altered rhyolite. Gravel is 

weathered. Abundance of limonite staining.

Sand with gravel and silt. 60 percent coarse- to fine-grained 

sand, 20 percent gravel, 20 percent silt. Light brown. Moist. 

Very consolidated. Rhyolite, minor pyrite, and fine-grained dark 

fragments. Limonite staining. Most fines washed away with

water.

TOP OF BENTONITE

PLUG: 100 FEET

BELOW LAND SURFACE

BELOW LAND SURFACE

0.010-INCH SLOT SCREEN

TOP OF SCREEN: 107 FEET

104 FEET BELOW LAND SURFACE

10/20 SILICA SAND

TOP OF FILTER PACK

80

90

100

110

120

130

140

70

DEPTH BELOW LAND SURFACE, IN FEET
Figure 8B. Well-completion data, lithologic log, and geophysical logs for SC–7A well.—Continued 

Well-completion data and lithologic log modified from Souder, Miller, and Associates (2003).

Hydraulic Testing to Determine Aquifer Characteristics 23

GAMMA ACTIVITY,

IN COUNTS PER SECOND

INDUCTION RESISTIVITY,

IN OHM-METERS

NEUTRON ACTIVITY,

IN COUNTS PER SECOND

40 140 240 20 40 60 1,000 2,000 3,000

80

90

100

110

120

130

140

70 8,437

8,407

8,417

8,427

8,377

8,387

8,397

8,367

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

DEPTH BELOW LAND SURFACE, IN FEET

(B) SC–7A well—Continued
Figure 8B. Well-completion data, lithologic log, and geophysical logs for SC–7A well.—Continued

Well-completion data and lithologic log modified from Souder, Miller, and Associates (2003).

24 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

WELL-COMPLETION DATA LITHOLOGIC LOG

(B) SC–7A well—Continued

TOTAL DEPTH 198 FEET

6-INCH THREADED CAP

BOTTOM OF SCREEN: 195 FEET 

BELOW LAND SURFACE

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

DEPTH BELOW LAND SURFACE, IN FEET

Sand with gravel and silt. 60 percent coarse- to 

fine-grained sand, 20 percent gravel, 20 percent silt. Dark 

brown. Moist. Very consolidated. Gravel composed of a 

variety of rock fragments. 

Sand with gravel and silt. 70 percent coarse- to 

fine-grained sand, 30 percent gravel, 20 percent silt. 

Dark brown. Wet. Too wet to sieve, all fragment sizes 

from 150 to 200 feet are estimated. Lithology same as 

above. 

Sand with gravel. 80 percent coarse- to fine-grained

sand, 20 percent gravel. Dark brown. Wet. Too ground up

by bit to identify.

Sand with gravel. 90 percent coarse- to fine-grained sand, 

10 percent gravel. Dark brown. Wet. Very hard to drill, 

hammer grinding up fragments. Quartz-flooded rhyolite.

Sand with gravel. 70 percent coarse- to fine-grained

sand, 30 percent gravel. Dark brown. Wet. Large gray 

andesite boulder with pyrite from 185 to 187 feet. 

Rhyolitic fragments with large quartz phenocrysts, 

fine-grained fragments with up to 0.4 percent pyrite. 

Limonite staining.

Sand with gravel. 70 percent coarse- to fine-grained sand, 

30 percent gravel. Dark brown. Wet. Rhyolite, andesite,

and fine-grained weathered fragments with epidote. 

Abundant pyrite. Limonite staining.

Initially drilled to 205 feet, but hole heaved up to 196 

feet before well installation. Flowing sand and gravel. 

200

190

180

170

160

150

140 8,367

8,357

8,347

8,327

8,337

8,317

8,307
Figure 8B. Well-completion data, lithologic log, and geophysical logs for SC–7A well.—Continued 

Well-completion data and lithologic log modified from Souder, Miller, and Associates (2003).

Hydraulic Testing to Determine Aquifer Characteristics 25

200

190

180

170

160

150

140 8,367

8,357

8,347

8,327

8,337

8,317

8,307

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

DEPTH BELOW LAND SURFACE, IN FEET

40 140 240 20 40 60 1,000 2,000 3,000

GAMMA ACTIVITY,

IN COUNTS PER SECOND

NEUTRON ACTIVITY,

IN COUNTS PER SECOND

INDUCTION RESISTIVITY,

IN OHM-METERS

(B) SC–7A well—Continued
Figure 8C. Well-completion data, lithologic log, and geophysical logs for SC–8A well. 

Well-completion data and lithologic log modified from Souder, Miller, and Associates (2003).

26  Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

PVC CAP

WELL-COMPLETION DATA LITHOLOGIC LOG

(C) SC–8A well

LOCKING METAL SHROUD

8 5/8-INCH OUTSIDE DIAMETER,

5 FEET LONG, 3-FOOT STICK-UP

ABOVE LAND SURFACE

3 FEET x 3 FEET x 1

FOOT CONCRETE PAD

4-INCH DIAMETER

SCHEDULE 80 PVC CASING

9-INCH DIAMETER

BOREHOLE

Sand with gravel. 55 percent coarse- to medium-grained 

sand, 45 percent gravel. Light tan to brown. Dry.

Rhyolite, quartz latite, and argillized fragments. Less 

than 0.1 percent pyrite. Limonite staining. Some ashflow fragments.

3/8-INCH HYDRATED

BENTONITE CHIPS

Sand with gravel. 70 percent coarse- to medium-grained 

sand, 30 percent gravel. Light tan. Dry. Lithologies same 

as above. In addition, andesite with epidote.

Boulder. Fine-grained quartz latite with abundant 

pyrite.

Sand with gravel. 65 percent coarse- to

medium-grained sand, 35 percent gravel. Light tan. 

Dry. Dacite porphyry, quartz latite, rhyolite. Minor 

pyrite.

Sand with gravel. 70 percent coarse- to medium-grained 

sand, 30 percent gravel. Light tan. Dry. Fine-grained 

fragments with quartz phenocrysts and pyrite. Rhyolite 

and highly weathered and argillized fragments.

Fine-grained dacite with epidote. Limonite staining.

TOP OF BENTONITE

PLUG: 76 FEET

BELOW LAND SURFACE

83 FEET BELOW LAND SURFACE

10/20 SILICA SAND

TOP OF FILTER PACK

DEPTH TO WATER 71 FEET BELOW LAND 

SURFACE MEASURED 

NOVEMBER 24, 2002

Gravel with sand and silt. 65 percent gravel, 30 percent 

coarse- to medium-grained sand, 5 percent silt. Dark 

brown. Dry. Rhyolite, dacite, latite, fine-grained

fragments with minor pyrite and some argillized 

fragments. Limonite staining. 

Gravel with sand and silt. 65 percent gravel, 30 percent 

coarse- to medium-grained sand, 5 percent silt. Dark 

brown. Moist. Lithologies same as above. In addition, 

andesite fragments with biotite alteration.

Gravel with sand and silt. 60 percent gravel, 35 percent 

coarse- to medium-grained sand, 5 percent silt. Dark 

brown. Wet. Rhyolite porphyry. 

BOTTOM OF SCREEN: 97 FEET 

BELOW LAND SURFACE

BELOW LAND SURFACE

0.010-INCH SLOT SCREEN

TOP OF SCREEN: 87 FEET

TOTAL DEPTH 98 FEET 6-INCH THREADED CAP

Gravel with sand and silt. 55 percent gravel, 40 percent 

coarse- to medium-grained sand, 5 percent silt. Dark 

brown. Very wet. Rhyolitic fragments. Limonite staining. 

DEPTH BELOW LAND SURFACE, IN FEET

90

80

60

70

50

30

40

20

10

100

0

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

8,468

8,448

8,428

8,438

8,458

8,398

8,378

8,388

8,408

8,418

8,368
Figure 8C. Well-completion data, lithologic log, and geophysical logs for SC–8A well.—Continued

Well-completion data and lithologic log modified from Souder, Miller, and Associates (2003).

50 125 200 10 35 60

GAMMA ACTIVITY,

IN COUNTS PER SECOND

ALTITUDE, ROUNDED TO NEAREST FOOT ABOVE NGVD 29

INDUCTION RESISTIVITY,

IN OHM-METERS

NEUTRON ACTIVITY,

IN COUNTS PER SECOND

DEPTH BELOW LAND SURFACE, IN FEET

500 2,000 3,500

90

80

60

70

50

30

40

20

10

100

0 8,468

8,448

8,428

8,438

8,458

8,398

8,378

8,388

8,408

8,418

8,368

(C) SC–8A well

Hydraulic Testing to Determine Aquifer Characteristics 27
geophysical log may be related to geologic conditions rather 

than a lack of moisture. 

In well SC–7A, resistivity measurements ranged from 

30 to 40 ohm-meters, and neutron counts ranged from 2,000 to 

3,000 cps from land surface to the water table, about 109 ft 

below land surface at the time logging was conducted. These 

values suggest that the deposits above the water table were dry 

to partially saturated (fig. 8B). 

In well SC–8A, typical resistivity measurements of about 

30 ohm-meters and typical neutron counts of about 2,000 to 

3,000 cps above the water table, about 71 ft below land surface 

at the time logging was conducted, indicate that these deposits 

were partially saturated (fig. 8C) though the water content 

may not have been high enough to note on the lithologic log. 

A slight increase in resistivity and decrease in gamma activity 

from 60 to 69 ft corresponds to the presence of gravel-sized 

deposits described in the driller’s log (fig. 8C). The increasing neutron count with depth in the screened interval (87.5 to 

97 ft) indicates that porosity decreased with depth in this 

interval. 

Hydraulic Testing to Determine Aquifer 

Characteristics

A flow-meter survey and several aquifer tests were 

conducted during 2003 to estimate the hydraulic properties of debris-flow deposits, bedrock, and Red River alluvial 

deposits in and near Straight Creek. A flow-meter survey was 

conducted in well SC–7A, slug tests were conducted in wells 

SC–1A, SC–1B, SC–2B, SC–3A, SC–3B, SC–4A, SC–5A, 

SC–5B, SC–6A, SC–7A, and SC–8A, and a pumping test was 

conducted at the mouth of the Straight Creek drainage in well 

AWWT–1. Wells AWWT–2, SC–5A, SC–5B, SC–7A and 

SC–8A were used to monitor ground-water levels during the 

pumping test. 

Flow-Meter Survey in Well SC–7A

A flow-meter survey was conducted in well SC–7A on 

October 27, 2003, to determine the vertical distribution of 

flow to the well through the interval open to the aquifer. The 

SC–7A well screen extends from about 107 ft to about 195 ft 

below land surface and, at the time of the test, was entirely 

below the water level in the well. 

Prior to the survey, a flow meter was lowered to about 

150 ft, and a pump was lowered to about 10 ft below the static 

water level (about 114 ft below land surface). The well was 

pumped at a rate of 3.64 gal/min (gallons per minute); this 

pumping rate was constant throughout the test. Drawdown in 

the well reached steady state at 0.07 ft below the static water 

level. The flow meter was raised and lowered incrementally in 

the well to measure the vertical distribution of flow produced 

by the pumping. The flow rates indicated the relative contribution of water to the well from each increment (fig. 9). 

Results of the flow-meter survey indicated that nearly 

all water entered well SC–7A from two zones—one approximately 10-ft-thick zone near the top of the screened interval 

(107–117 ft below land surface) and one approximately 15-ftthick zone near the bottom of the screened interval (177–192 ft 

below land surface). About 77 percent of the water entered 

the well through the upper zone, and about 23 percent of the 

water entered the well through the lower zone (fig. 9); less 

than 1 percent of the water entered the well between these two 

zones. The lithologic log of well SC–7A (fig. 8B) indicates 

that boulders were present within both of these zones. 

Slug Tests Conducted in Selected Phase I and II 

Drilled Wells

Slug tests were performed in wells SC–1A, SC–1B, 

SC–2B, SC–3A, SC–3B, SC–4A, SC–5A, SC–5B, SC–6A, 

SC–7A, and SC–8A during June 3–5, 2003. Water-level data 

were recorded during each slug test using a submersible pressure transducer connected to a data logger. The data logger 

was programmed to collect data in the early stages of slug tests 

at a rate of once every 0.125 second, and in the later stages of 

slug tests at a rate of once every 5 seconds. Water in the wells 

was displaced (raised or lowered) by means of a slug, a sealed 

2-in. outside diameter, 5.5-ft long, schedule 80 PVC pipe filled 

with sand. Slug tests were performed using both slug-in and 

slug-out techniques.

The slug-in test procedure was as follows. The static 

water level in the well was measured using an electric tape 

shortly before introduction of the slug. The slug was lowered 

to just above the static water level in the well. Then, data logger recording was initiated shortly before the slug was rapidly 

and completely submerged below the static water level in the 

well. 

The slug-out procedure, usually done following a slug-in 

test, was as follows. The water level in the well was measured using an electric tape to determine if the water level had 

returned to the static level, and then data logger recording was 

initiated shortly before the slug was rapidly and completely 

removed from the well. 

All slug-test data except that from wells SC–7A and 

SC–8A were analyzed using the method of Bouwer and Rice 

(1976) as implemented in the AQTESOLV computer program 

(Duffield, 2000). Water levels in wells SC–7A and SC–8A 

exhibited oscillatory behavior (oscillations from above to 

below the static water level) during slug tests and, therefore, 

were analyzed using the method of van der Kamp (1976) as 

implemented in the van der Kamp spreadsheet developed by 

Halford and Kuniansky (2002). The van der Kamp (1976) 

method assumes that the well screen fully penetrates the 

saturated aquifer—a condition met for well SC–7A but not for 

well SC–8A. Thus, an estimated range of likely hydraulicconductivity values is reported for well SC–8A. Analytical 

28  Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15
solutions within both the AQTESOLV program and the van 

der Kamp spreadsheet were obtained by manually fitting 

straight-line segments to the data.

Because of the limited radius of investigation of a slug 

test (Halford and Kuniansky, 2002), the aquifer interval 

contributing water during a slug test was assumed to be the 

aquifer interval adjacent to the well screen. During installation, the SC–1A, SC–3A, SC–4A, SC–5A, and SC–6A well 

screens were placed primarily in Straight Creek debris-flow 

deposits, but some of these screens also penetrated bedrock. 

For consistency, hydraulic-conductivity values were estimated 

for that part of the each well’s screen that was in debris-flow 

deposits. Hydraulic-conductivity values were estimated for a 

vertical-to-horizontal hydraulic-conductivity ratio of 0.01.

On the basis of the above variables, hydraulic-conductivity values were estimated for the wells (table 2). For the wells 

with screens in debris-flow deposits (wells SC–1A, SC–3A, 

SC–4A, and SC–6A), the mean and median estimated hydraulic conductivities were 15.25 and 15.35 ft/d (feet per day), 

respectively. For the wells with screens in bedrock (wells

SC–1B, SC–2B, SC–3B, and SC–5B), the mean and median 

estimated hydraulic conductivities were 0.12 and 0.08 ft/d, 

respectively (table 2). For the wells with screens in mixed 

debris-flow deposits and Red River alluvium (wells SC–5A, 

SC–7A, and SC–8A), the mean and median estimated hydraulic conductivities were 73–207 (estimated range) and 80 ft/d. 

Although there is some overlap of the estimated hydraulicconductivity values between the groups of wells, the mean 

and median values indicate that, in general, bedrock has the 

smallest hydraulic conductivity, debris-flow deposits have the 

next highest hydraulic conductivity, and mixed debris-flow 

deposits and Red River alluvium have the largest hydraulic 

conductivity. 

Variations in hydraulic conductivity over short distances, 

such as between wells SC–3A, SC–4A, and SC–6A, are an 

indication of the heterogeneity of the debris-flow deposits. 

The variations in estimated hydraulic conductivity are consistent with field observations along Straight Creek such as the 

debris-flow deposits consist of massive beds with discontinuous layers of poorly sorted clay- to boulder-size material that 

may be interlayered with thin beds, generally less than a foot 

thick, of well-sorted sand and gravel. Thus, wells separated by 

short distances can exhibit very different hydraulic properties.

It is interesting to note that for the wells with screens in 

mixed debris-flow deposits and Red River alluvium, the largest hydraulic conductivity was estimated for the well (SC–8A) 

Figure 9. Vertical distribution of borehole flow measured during 

pumping and corresponding percentage of flow into well SC-7A.

Table 2. Estimated hydraulic-conductivity values for slug tests conducted June 3–5, 2003, for selected wells in Red River Valley, northcentral New Mexico.

[e, estimated value—actual value probably is within the indicated range. The actual value is uncertain because the well screen did not fully penetrate the aquifer as assumed by the van der Kamp (1976) method]

Hydraulic conductivity, in feet per day

Wells completed in debris-flow deposits

SC–1A SC–3A SC–4A SC–6A Mean Median

0.7 0.3 30 30 15.25 15.35

Wells completed in bedrock

SC–1B SC–2B SC–3B SC–5B Mean Median

0.06 0.1 0.005 0.3 0.12 0.08

Wells completed in mixed Red River alluvium and debris-flow deposits

SC–5A SC–7A SC–8A Mean Median

40 80 e 100–500 e 73–207 80

200

180

160

140

120

100

UPFLOW DURING PUMPING,

IN GALLONS PER MINUTE 

PERCENT FLOW INTO WELL

23 Percent 

77 Percent 

0 2 1 3 4 5 0 20 40 60 80 100

DEPTH, IN FEET BELOW LAND SURFACE

Hydraulic Testing to Determine Aquifer Characteristics 29
closest to the axis of the Red River Valley. This may be an 

indication that debris-flow deposits near the central part of the 

Red River Valley (or farther away from the source of debrisflow material) are more likely to be reworked and sorted into 

hydraulically transmissive alluvial deposits than are the debrisflow deposits near margins of the valley.

Pumping Test Conducted at Mouth of Straight 

Creek Drainage

A pumping test was conducted to estimate the hydraulic 

properties of mixed debris-flow deposits and Red River alluvium at the mouth of the Straight Creek drainage. The aquifer 

test was conducted December 3–4, 2003, using well AWWT–1 

as the pumped well, and wells AWWT–2, SC–5A, SC–5B, 

SC–7A, and SC–8A as observation wells. Well AWWT–2 is 

completed in bedrock that is horizontally adjacent to mixed 

debris flow and Red River alluvium, but water levels in the 

well did not show a measurable response to pumping (discussed later in this report); therefore, it was not used in the 

aquifer-test analysis. Well SC–5B is completed in bedrock; 

wells AWWT–1, SC–5A, SC–7A, and SC–8A are completed 

in mixed debris-flow deposits and Red River alluvium. 

The pumping test was conducted as follows. Pressure 

transducers were installed in wells AWWT–1, AWWT–2, 

SC–7A, and SC–8A on November 22, 2003, to allow for 

measurement of pre-pumping water-level trends. Wells SC–5A 

and SC–5B had been equipped previously with pressure 

transducers. During the week of December 1, 2003, a submersible pump was installed in well AWWT–1. Pumping for 

the aquifer test began at 2:05 p.m. on December 3, 2003. The 

pumping rate was monitored using a totalizing flow meter 

located near the well head. The measured pumping rate ranged 

from 104.5 to 108.6 gal/min with a time-weighted average 

of 106 gal/min. The water from well AWWT–1 was pumped 

into a nearby unused sewage lagoon. Water levels measured 

by pressure transducers in the pumped well and in the observation wells were recorded by a data logger eight times per 

second for the first minute of the test, once a second for the 

next 9 minutes, and then the recording interval was increased 

over time to a maximum of 15 minutes. Barometric pressure 

also was recorded prior to and during the pumping test for use 

in correcting the water-level data for changes in barometric 

pressure. 

Pre-pumping monitoring indicated that water levels were 

rising in all of the pumping-test wells from late November 

to about December 2, 2003, (fig. 10A). Water levels stopped 

rising on December 3, just prior to initiation of the pumping 

test, and began falling after initiation of pumping. Pre-pumping monitoring indicated that water-level variations in well 

AWWT–2 closely followed variations in barometric pressure 

and that the water-level variations caused by barometricpressure changes masked any observable water-level change 

caused by pumping well AWWT–1 (fig. 10B). Other wells 

did not show a discernable relation between water-level and 

barometric-pressure changes.

The change in water-level trends just prior to initiation of 

the pumping test makes the corrections in drawdown measured during the test difficult for all but the pumping well. The 

drawdown in the pumping well was relatively large compared 

with the water-level-trend changes. But, drawdowns measured 

in the observation wells were relatively small compared to the 

changing water-level trends. Pre- and post-test water levels 

from wells AWWT–1, SC–5A, SC–5B, and SC–7A were used 

to correct for water-level trends not attributed to the test pumping. However, because of the changing trends in background 

water levels, corrected drawdown from the early part of the 

test was considered more reliable than corrected drawdown 

from the later part of the test. Therefore, the early part of the 

test was used in the test analysis.

Analysis of the pumping test water-level data from wells 

SC–5A and SC–7A using standard curve-matching techniques 

and type curves for non-steady radial flow (Theis, 1935) indicated that estimated transmissivity was 12,000 to 34,000 ft2

/d 

(feet squared per day), and estimated hydraulic conductivity 

was 230 to 340 ft/d (table 3). Pumping-test data from wells 

AWWT–2 and SC–8A were not analyzed because the water 

levels in these wells did not visibly respond to pumping. Data 

from well AWWT–1 was not analyzed because most of the 

drawdown in the well probably resulted from hydraulic head 

losses that occurred as ground-water flowed in through the 

well screen. The water-level response to pumping in well 

SC–5B was judged to be a pressure response and an indication 

of hydraulic connection between bedrock and the overlying 

mixed debris-flow deposits and Red River alluvium. 

Water-Level Measurements

Periodic manual water-level measurements were made at 

each observation well using a steel or electric tape. Measurements were recorded to the nearest 0.01 ft and were repeated 

until the precision was within 0.02 ft. 

Hydrographs of manually measured water-level altitudes 

in Phase II wells, except well SC-9A, are shown in 

figures 11–13. Streamflow and stage in the Red River also are 

shown in figure 11. The hydrographs of water levels in the 

Capulin Canyon wells (fig. 13) include measurements made 

by the USGS and the measurements made by URS, Denver, 

Colorado, a private consultant contracted by Molycorp. 

The land-surface altitude was used to establish a datum 

for each observation well. A permanent measuring point for 

water-level measurement was established at each well, and 

the distance of this measuring point above land surface was 

determined. Description and distance above land surface of 

measuring points for Phase I and II wells are listed in table 4. 

Ground-water altitudes in observation wells were calculated 

by subtracting the depth to water below the permanent 

measuring point, minus the height of the permanent measur-

30 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15
Figure 10. (A) Water levels in wells AWWT–1, SC–5A, SC–5B, SC–7A, and SC–8A before, during, and after pumping test and 

(B) comparison of water levels in well AWWT–2 to barometric pressure, November 22–December 5, 2003. 

8,396

8,414

8,398

8,412

8,410

8,408

8,402

8,400

8,404

8,406

103.4

104.6

103.6

103.8

104.2

104.4

104.0

22 1 5

November 2003 December 2003

23 24 25 26 27 28 29 30 2 3 4

24.2

25.6

24.4

24.6

24.8

25.0

25.2

25.4

Well AWWT–2

BAROMETRIC PRESSURE

Well SC–5B

Well SC–5A

Well AWWT–1

Well SC–7A

Well SC–8A

WATER LEVEL, IN FEET ABOVE DATUM OF NGVD 29 WATER LEVEL, IN FEET BELOW TOP OF WELL CASING

BAROMETRIC PRESSURE, IN FEET OF WATER

(A)

(B)

Water-Level Measurements  31
ing point above land surface, from the land-surface altitude. 

Water-level altitudes for Phase I and II wells are listed in 

table 4. Water levels in Phase I wells included in table 4 have 

not been previously published. Naus and others (2005) discuss 

water levels measured in Phase I wells during 2002 and 2003. 

Water levels in the Phase II drilled wells SC–6A, SC–7A, 

SC–8A, and the Hottentot, Hansen, and La Bobita wells typically rose rapidly during the melting of the winter snowpack 

in the springtime and then generally declined during the rest 

of the year. The Red River streamflow hydrograph (fig. 11A) 

indicates that most meltwater from the winter snowpack 

entered the river during April and May. Water levels in these 

wells were measured periodically and, therefore, may not 

coincide precisely with the beginning and ending of waterlevel rises in response to spring snowmelt. The duration of 

water-level rise, however, appears to be typically about 2 

months, after which a slow water-level decline occurs during 

the following 10 months. 

Wells SC–6A, SC–7A and SC–8A are completed in 

unconsolidated deposits; well SC6–A is completed in debrisflow deposits, and wells SC–7A and SC–8A are most likely 

completed in mixed debris-flow deposits and Red River 

alluvium. Wells SC–6A, SC–7A, and SC–8A are about 2,200, 

400, and 100 ft north of the Red River, respectively. 

In the Straight Creek drainage, the water-level rise in 

response to spring snowmelt occurred earlier and was smaller 

at greater distances from the Red River. The water level in well 

SC–6A rose 1.88 ft between February 7 and April 15, 2003, 

and 1.85 ft between February 20 and May 12, 2004 (fig. 11B); 

water levels in wells SC–7A and SC–8A rose 13.71 and 

13.02 ft between April 17 and June 5, 2003, and 14.00 and 

13.56 ft between March 26 and June 1, 2004, respectively 

(figs. 11C and 11D). The springtime increases in water levels 

in wells SC7–A and SC–8A were about eight times larger than 

those in well SC-6A (fig. 11). The magnitude of subsequent 

water-level declines in wells SC–6A, SC–7A and SC–8A 

during the following approximately 10 months were similarly 

related to distance from the Red River (fig. 11). The water 

level in well SC–6A declined 1.73 ft during the approximately 

10 months between April 15, 2003, and February 20, 2004; 

water levels in wells SC–7A and SC–8A declined 12.71 and 

12.05 ft, respectively, during the approximately 10 months 

between June 5, 2003, and March 26, 2004. 

Well SC–9A is about 7 ft from the north bank of the Red 

River and about 100 ft south of well SC–8A (fig. 3). This well 

was dry at the time of construction but subsequently contained water. Three water levels in well SC–9A measured on 

March 26, May 12, and June 1, 2004, ranged from 12.02 to 

25.58 ft above concurrently measured water levels in well SC–

8A. On May 12, 2004, the stage of the Red River was 31.5 ft 

above the water level in well SC–8A and 16.2 ft higher than 

the water level in well SC–9A. This substantially higher stage 

in the Red River compared with water levels in wells SC–8A 

and SC–9A, and the absence of water in well SC–9A and 

nearby holes at the time of completion of well SC–9A, indicate that the Red River had a poor hydraulic connection to the 

underlying ground-water system and the surface-water system 

is perched above the ground-water system at this site. 

The Hottentot well, completed in debris-flow deposits, 

is about 1,700 ft north of the Red River and about 0.75 mi 

upstream (east) from Straight Creek. The water level in the 

Hottentot well rose 1.69 ft between February 5 and May 12, 

2003, and 2.80 ft between March 26 and May 12, 2004 

(fig. 12A). The water level declined 0.77 ft during the 

approximately 10 months between May 12, 2003, and 

March 26, 2004.

The Hansen well is completed in debris-flow deposits 

and is about 1,500 ft north of the Red River and about 0.75 mi 

downstream (west) from Straight Creek. The water level in 

the Hansen well rose 3.96 ft between February 5 and April 17, 

2003, and 2.83 ft between February 20 and May 11, 2004 

(fig. 12B). The water level declined 3.79 ft during the approximately 10 months between measurements on April 17, 2003, 

and February 20, 2004.

The La Bobita well is completed in unconsolidated 

deposits not associated with debris-flow deposits. The well 

is about 600 ft northwest of the Red River and about 2 mi 

downstream (west) from Straight Creek. The water level in the 

La Bobita well rose 5.49 ft between February 7 and May 15, 

2003, and 4.68 ft between March 26 and May 13, 2004 

(fig. 12C). The water level declined 4.57 ft during the approximately 10 months between measurements on May 15, 2003, 

and March 26, 2004.

Wells in Capulin Canyon are about 1 mi northeast of 

the Red River. Wells CC–1A and CC–2A are completed 

in Capulin Canyon alluvium, well CC–1B is completed in 

bedrock or overlying regolith, and well CC–2B is completed 

in bedrock. The hydrographs for each of these four wells are 

similar (fig. 13). A seasonal high in water level occurs during 

spring snowmelt in April or May 2003, a seasonal low in July 

2003, and then a second seasonal high in September 2003. 

The spring seasonal high occurs again in April 2004. The 

range in water levels at wells CC–1A and CC–2A (completed 

in alluvium) were about 1.8 times the range in wells CC–1B 

and CC–2B (completed in regolith or bedrock), respectively 

(fig. 13). 

32 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Table 3. Results of pumping test conducted December 3–4, 2003, in selected wells in Red River Valley, north-central New Mexico.

Well

(fig. 3)

Estimated transmissivity 

(feet squared per day)

Estimated saturated thickness 

(feet)

Estimated hydraulic conductivity 

(feet per day)

SC–5A 12,000 52 230

SC–7A 34,000 99 340
Figure 11. (A) Daily mean streamflow and stage of the Red River near Questa and (B–D) ground-water altitudes in wells SC–6A, 

SC–7A, and SC–8A, February 2003–June 2004. 

8,595

8,600

8,605

8,610

8,615

8,620

8,395

8,400

8,405

8,410

8,415

8,420

2003

Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2004

Jan. Feb. Mar. Apr. May June 8,395

8,400

8,405

8,410

8,415

8,420

0

25

50

75

100

125

150

1

2

3

4

STREAMFLOW

STAGE

RED RIVER NEAR QUESTA

Well SC–6A

Well SC–7A

Well SC–8A

(A)

(B)

(C)

(D)

ALTITUDE, IN FEET ABOVE NGVD 29

STREAMFLOW, IN CUBIC

FEET PER SECOND

STAGE, IN FEET

MISSING

ABOVE GAGE DATUM

DATA

Water-Level Measurements  33
Phase III wells were installed in unconsolidated material 

along an approximately 1-mi reach of the Red River west of 

Elephant Rock campground (figs. 1 and 4). These wells were 

installed to examine the interaction of the Red River and water 

in the Red River alluvium. Water levels in these wells were 

measured in December 2003 and in February, March, May, 

and June 2004. The difference in altitude between the water 

level in these wells and the stage of the Red River also was 

determined from survey data collected in May and June 2004. 

Water-level altitudes in the Phase II La Bobita well and all 

Phase III wells and altitude of the stage of the Red River are 

listed in table 5; a comparison of water levels in the La Bobita 

well and Phase III wells with the stage of the Red River is 

shown in figure 14.

Well 1 was installed about 150 ft downstream (west) 

from a line approximately perpendicular to the Red River 

and connecting to the La Bobita well (fig. 4). Water levels 

measured in May and June 2004 in the La Bobita well ranged 

from 2.95 to 3.52 ft higher than concurrently measured water 

levels in well 1 (fig. 14, table 5). Considering the locations of 

these two wells, the relative water levels indicate that ground 

water is flowing toward the Red River. The stage of the Red 

River also was measured in May and June 2004 where a line 

approximately perpendicular to the bank of the river intersects 

the La Bobita well. Ground-water levels in the La Bobita well 

ranged from 7.1 to 6.7 ft lower and in well 1 ranged from 

10.1 to 9.8 ft lower than the stage of the Red River (fig. 14, 

table 5). This indicates that, near these wells, the Red River 

is perched above the water table and may be disconnected 

from or have a poor hydraulic connection to the underlying 

ground water. 

34 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Figure 12. Ground-water altitudes in (A) Hottentot, (B) Hansen, and (C) La Bobita wells, February 2003–June 2004.

8,166

8,168

8,170

8,172

8,174

8,176

LA BOBITA WELL

8,460

8,462

8,464

8,466

8,468

8,470

HANSEN WELL

(A)

8,690

8,692

8,694

8,696

8,698

8,700

HOTTENTOT WELL

(B)

(C)

2003

Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2004

Jan. Feb. Mar. Apr. May June

ALTITUDE, IN FEET ABOVE NGVD 29
Water-Level Measurements  35

Figure 13. Ground-water altitudes in wells (A) CC–1A, (B) CC-1B, (C) CC–2A, and (D) CC–2B, February 2003–April 2004. Data 

collected by URS, Denver, Colorado, and U.S. Geological Survey (USGS) personnel.

8,870

8,872

8,874

8,876

8,878

8,880

USGS

URS

8,866

8,868

8,870

8,872

8,874

8,876

8,866

8,868

8,870

8,872

8,874

8,876

8,866

8,868

8,870

8,872

8,874

8,876

Well CC–1A

(A)

Well CC–1B

(B)

Well CC–2A

(C)

Well CC–2B

(D)

ALTITUDE, IN FEET ABOVE NGVD 29

2003

Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2004

Jan. Feb. Mar. Apr.

URS

URS

URS

USGS

USGS

USGS
36  Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04. 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase I wells

SC–1A 03/15/02 Top of casing 52.51 +0.12 52.39 2.88 49.51 8,904.44 8,854.94

SC–1A 03/18/02 Top of casing 52.51 +0.12 52.39 2.88 49.51 8,904.44 8,854.94

SC–1A 03/26/02 Access hole in cap 52.32 0.00 52.32 2.88 49.44 8,904.44 8,855.00

SC–1A 04/25/02 Access hole in cap 52.44 0.00 52.44 2.88 49.56 8,904.44 8,854.88

SC–1A 05/22/02 Access hole in cap 52.65 0.00 52.65 2.88 49.77 8,904.44 8,854.67

SC–1A 06/18/02 Access hole in cap 52.73 0.00 52.73 2.88 49.85 8,904.44 8,854.59

SC–1A 07/24/02 Access hole in cap 52.85 0.00 52.85 2.88 49.97 8,904.44 8,854.47

SC–1A 08/21/02 Access hole in cap 52.48 0.00 52.48 2.88 49.60 8,904.44 8,854.84

SC–1A 09/17/02 Access hole in cap 52.71 0.00 52.71 2.88 49.83 8,904.44 8,854.61

SC–1A 10/16/02 Access hole in cap 51.94 0.00 51.94 2.88 49.06 8,904.44 8,855.38

SC–1A 11/14/02 Access hole in cap 52.30 0.00 52.30 2.88 49.42 8,904.44 8,855.02

SC–1A 12/12/02 Access hole in cap 52.39 0.00 52.39 2.88 49.51 8,904.44 8,854.93

SC–1A 02/03/03 Access hole in cap 52.61 0.00 52.61 2.88 49.73 8,904.44 8,854.71

SC–1A 04/16/03 Access hole in cap 51.50 0.00 51.50 2.88 48.62 8,904.44 8,855.82

SC–1A 05/13/03 Access hole in cap 51.91 0.00 51.91 2.88 49.03 8,904.44 8,855.41

SC–1A 06/02/03 Access hole in cap 52.45 0.00 52.45 2.88 49.57 8,904.44 8,854.87

SC–1A 06/06/03 Access hole in cap 52.48 0.00 52.48 2.88 49.60 8,904.44 8,854.84

SC–1A 07/08/03 Access hole in cap 52.48 0.00 52.48 2.88 49.60 8,904.44 8,854.84

SC–1A 08/21/03 Access hole in cap 52.45 0.00 52.45 2.88 49.57 8,904.44 8,854.87

SC–1A 09/18/03 Access hole in cap 51.99 0.00 51.99 2.88 49.11 8,904.44 8,855.33

SC–1A 10/20/03 Access hole in cap 52.45 0.00 52.45 2.88 49.57 8,904.44 8,854.87

SC–1A 10/23/03 Access hole in cap 52.48 0.00 52.48 2.88 49.60 8,904.44 8,854.84

SC–1A 12/05/03 Access hole in cap 52.61 0.00 52.61 2.88 49.73 8,904.44 8,854.71

SC–1A 02/21/04 Access hole in cap 52.61 0.00 52.61 2.88 49.73 8,904.44 8,854.71

SC–1A 03/26/04 Access hole in cap 51.58 0.00 51.58 2.88 48.70 8,904.44 8,855.74

SC–1A 05/11/04 Access hole in cap 51.45 0.00 51.45 2.88 48.57 8,904.44 8,855.87

SC–1A 06/01/04 Access hole in cap 52.45 0.00 52.45 2.88 49.57 8,904.44 8,854.87

SC–1B 03/15/02 Top of casing 59.02 +0.12 58.90 3.15 55.75 8,901.88 8,846.13

SC–1B 03/18/02 Top of casing 59.01 +0.12 58.89 3.15 55.74 8,901.88 8,846.14

SC–1B 03/26/02 Access hole in cap 58.88 0.00 58.88 3.15 55.73 8,901.88 8,846.15
Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase I wells—Continued

SC–1B 04/25/02 Access hole in cap 59.00 0.00 59.00 3.15 55.85 8,901.88 8,846.03

SC–1B 05/22/02 Access hole in cap 59.12 0.00 59.12 3.15 55.97 8,901.88 8,845.91

SC–1B 06/18/02 Access hole in cap 59.66 0.00 59.66 3.15 56.51 8,901.88 8,845.37

SC–1B 07/24/02 Access hole in cap 59.29 0.00 59.29 3.15 56.14 8,901.88 8,845.74

SC–1B 08/21/02 Access hole in cap 59.00 0.00 59.00 3.15 55.85 8,901.88 8,846.03

SC–1B 09/17/02 Access hole in cap 59.25 0.00 59.25 3.15 56.10 8,901.88 8,845.78

SC–1B 10/16/02 Access hole in cap 58.37 0.00 58.37 3.15 55.22 8,901.88 8,846.66

SC–1B 11/14/02 Access hole in cap 58.78 0.00 58.78 3.15 55.63 8,901.88 8,846.25

SC–1B 12/12/02 Access hole in cap 58.83 0.00 58.83 3.15 55.68 8,901.88 8,846.20

SC–1B 02/03/03 Access hole in cap 58.87 0.00 58.87 3.15 55.72 8,901.88 8,846.16

SC–1B 04/16/03 Access hole in cap 57.38 0.00 57.38 3.15 54.23 8,901.88 8,847.65

SC–1B 05/13/03 Access hole in cap 58.09 0.00 58.09 3.15 54.94 8,901.88 8,846.94

SC–1B 06/02/03 Access hole in cap 58.63 0.00 58.63 3.15 55.48 8,901.88 8,846.40

SC–1B 06/06/03 Access hole in cap 58.60 0.00 58.60 3.15 55.45 8,901.88 8,846.43

SC–1B 07/08/03 Access hole in cap 58.54 0.00 58.54 3.15 55.39 8,901.88 8,846.49

SC–1B 08/21/03 Access hole in cap 58.58 0.00 58.58 3.15 55.43 8,901.88 8,846.45

SC–1B 09/18/03 Access hole in cap 57.99 0.00 57.99 3.15 54.84 8,901.88 8,847.04

SC–1B 10/20/03 Access hole in cap 58.34 0.00 58.34 3.15 55.19 8,901.88 8,846.69

SC–1B 12/05/03 Access hole in cap 58.49 0.00 58.49 3.15 55.34 8,901.88 8,846.54

SC–1B 02/21/04 Access hole in cap 58.42 0.00 58.42 3.15 55.27 8,901.88 8,846.61

SC–1B 03/26/04 Access hole in cap 57.53 0.00 57.53 3.15 54.38 8,901.88 8,847.50

SC–1B 05/11/04 Access hole in cap 57.11 0.00 57.11 3.15 53.96 8,901.88 8,847.92

SC–1B 06/01/04 Access hole in cap 58.03 0.00 58.03 3.15 54.88 8,901.88 8,847.00

SC–2B 03/15/02 Top of casing 70.95 +0.12 70.83 2.59 68.24 8,737.35 8,669.11

SC–2B 03/19/02 Top of casing 70.81 +0.12 70.69 2.59 68.09 8,737.35 8,669.26

SC–2B 03/25/02 Access hole in cap 70.66 0.00 70.66 2.59 68.07 8,737.35 8,669.28

SC–2B 04/25/02 Access hole in cap 71.05 0.00 71.05 2.59 68.46 8,737.35 8,668.89

SC–2B 05/23/02 Access hole in cap 71.23 0.00 71.23 2.59 68.64 8,737.35 8,668.71

SC–2B 06/25/02 Access hole in cap 71.44 0.00 71.44 2.59 68.85 8,737.35 8,668.50

SC–2B 07/25/02 Access hole in cap 71.72 0.00 71.72 2.59 69.13 8,737.35 8,668.22

Water-Level Measurements  37
38  Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase I wells—Continued

SC–2B 08/21/02 Access hole in cap 71.40 0.00 71.40 2.59 68.81 8,737.35 8,668.54

SC–2B 09/18/02 Access hole in cap 71.06 0.00 71.06 2.59 68.47 8,737.35 8,668.88

SC–2B 10/17/02 Access hole in cap 67.74 0.00 67.74 2.59 65.15 8,737.35 8,672.20

SC–2B 11/14/02 Access hole in cap 69.27 0.00 69.27 2.59 66.68 8,737.35 8,670.67

SC–2B 12/12/02 Access hole in cap 69.94 0.00 69.94 2.59 67.35 8,737.35 8,670.00

SC–2B 02/08/03 Access hole in cap 70.77 0.00 70.77 2.59 68.18 8,737.35 8,669.17

SC–2B 04/15/03 Access hole in cap 69.63 0.00 69.63 2.59 67.04 8,737.35 8,670.31

SC–2B 06/03/03 Top of casing 69.65 +0.12 69.53 2.59 66.94 8,737.35 8,670.41

SC–2B 06/06/03 Access hole in cap 69.75 0.00 69.75 2.59 67.16 8,737.35 8,670.19

SC–2B 07/09/03 Access hole in cap 70.62 0.00 70.62 2.59 68.03 8,737.35 8,669.32

SC–2B 08/22/03 Access hole in cap 71.09 0.00 71.09 2.59 68.50 8,737.35 8,668.85

SC–2B 09/18/03 Access hole in cap 69.96 0.00 69.96 2.59 67.37 8,737.35 8,669.98

SC–2B 10/20/03 Access hole in cap 70.08 0.00 70.08 2.59 67.49 8,737.35 8,669.86

SC–2B 12/05/03 Access hole in cap 70.79 0.00 70.79 2.59 68.20 8,737.35 8,669.15

SC–2B 02/20/04 Access hole in cap 71.41 0.00 71.41 2.59 68.82 8,737.35 8,668.53

SC–2B 03/25/04 Access hole in cap 68.44 0.00 68.44 2.59 65.85 8,737.35 8,671.50

SC–2B 05/12/04 Access hole in cap 68.38 0.00 68.38 1.59 66.79 8,737.35 8,670.56

SC–2B 06/01/04 Access hole in cap 69.08 0.00 69.08 2.59 66.49 8,737.35 8,670.86

SC–3A 03/15/02 Top of casing 70.53 +0.12 70.41 2.61 67.80 8,735.87 8,668.08

SC–3A 03/19/02 Top of casing 70.92 +0.12 70.80 2.61 68.19 8,735.87 8,667.69

SC–3A 03/25/02 Access hole in cap 71.53 0.00 71.53 2.61 68.92 8,735.87 8,666.95

SC–3A 04/24/02 Access hole in cap 71.95 0.00 71.95 2.61 69.34 8,735.87 8,666.53

SC–3A 05/23/02 Access hole in cap 72.03 0.00 72.03 2.61 69.42 8,735.87 8,666.45

SC–3A 06/19/02 Access hole in cap 72.38 0.00 72.38 2.61 69.77 8,735.87 8,666.10

SC–3A 07/25/02 Access hole in cap 72.64 0.00 72.64 2.61 70.03 8,735.87 8,665.84

SC–3A 08/21/02 Access hole in cap 72.52 0.00 72.52 2.61 69.91 8,735.87 8,665.96

SC–3A 09/18/02 Access hole in cap 72.28 0.00 72.28 2.61 69.67 8,735.87 8,666.20

SC–3A 10/17/02 Access hole in cap 68.92 0.00 68.92 2.61 66.31 8,735.87 8,669.56

SC–3A 11/14/02 Access hole in cap 70.27 0.00 70.27 2.61 67.66 8,735.87 8,668.21

SC–3A 12/12/02 Access hole in cap 70.54 0.00 70.54 2.61 67.93 8,735.87 8,667.94
Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase I wells—Continued

SC–3A 02/08/03 Access hole in cap 72.00 0.00 72.00 2.61 69.39 8,735.87 8,666.48

SC–3A 04/15/03 Access hole in cap 68.57 0.00 68.57 2.61 65.96 8,735.87 8,669.91

SC–3A 05/14/03 Access hole in cap 68.30 0.00 68.30 2.61 65.69 8,735.87 8,670.18

SC–3A 06/06/03 Top of casing 69.62 +0.12 69.50 2.61 66.89 8,735.87 8,668.98

SC–3A 07/09/03 Access hole in cap 70.99 0.00 70.99 2.61 68.38 8,735.87 8,667.49

SC–3A 08/21/03 Access hole in cap 71.67 0.00 71.67 2.61 69.06 8,735.87 8,666.81

SC–3A 09/18/03 Access hole in cap 71.25 0.00 71.25 2.61 68.64 8,735.87 8,667.23

SC–3A 10/20/03 Access hole in cap 70.48 0.00 70.48 2.61 67.87 8,735.87 8,668.00

SC–3A 10/21/03 Access hole in cap 70.50 0.00 70.50 2.61 67.89 8,735.87 8,667.98

SC–3A 12/05/03 Access hole in cap 71.56 0.00 71.56 2.61 68.95 8,735.87 8,666.92

SC–3A 12/05/03 Access hole in cap 71.56 0.00 71.56 2.61 68.95 8,735.87 8,666.92

SC–3A 02/20/04 Access hole in cap 72.24 0.00 72.24 2.61 69.63 8,735.87 8,666.24

SC–3A 03/25/04 Access hole in cap 70.85 0.00 70.85 2.61 68.24 8,735.87 8,667.63

SC–3A 05/12/04 Access hole in cap 67.12 0.00 67.12 1.61 65.51 8,735.87 8,670.36

SC–3A 06/01/04 Access hole in cap 68.77 0.00 68.77 2.61 66.16 8,735.87 8,669.71

SC–3B 03/15/02 Top of casing 156.33 0.00 156.32 2.50 153.82 8,735.38 8,581.56

SC–3B 03/19/02 Top of casing 156.34 0.00 156.34 2.50 153.84 8,735.38 8,581.54

SC–3B 03/26/02 Access hole in cap 156.32 0.00 156.32 2.50 153.82 8,735.38 8,581.56

SC–3B 04/25/02 Access hole in cap 156.06 0.00 156.06 2.50 153.56 8,735.38 8,581.82

SC–3B 06/25/02 Access hole in cap 156.31 0.00 156.31 2.50 153.81 8,735.38 8,581.57

SC–3B 07/25/02 Access hole in cap 156.25 0.00 156.25 2.50 153.75 8,735.38 8,581.63

SC–3B 08/21/02 Access hole in cap 156.31 0.00 156.31 2.50 153.81 8,735.38 8,581.57

SC–3B 09/18/02 Access hole in cap 156.16 0.00 156.16 2.50 153.66 8,735.38 8,581.72

SC–3B 10/17/02 Access hole in cap 155.40 0.00 155.40 2.50 152.90 8,735.38 8,582.48

SC–3B 11/14/02 Access hole in cap 155.40 0.00 155.40 2.50 152.90 8,735.38 8,582.48

SC–3B 12/12/02 Access hole in cap 155.28 0.00 155.28 2.50 152.78 8,735.38 8,582.60

SC–3B 02/08/03 Access hole in cap 155.52 0.00 155.52 2.50 153.02 8,735.38 8,582.36

SC–3B 04/15/03 Access hole in cap 154.83 0.00 154.83 2.50 152.33 8,735.38 8,583.05

SC–3B 05/14/03 Access hole in cap 154.51 0.00 154.51 2.50 152.01 8,735.38 8,583.37

SC–3B 06/03/03 Top of casing 154.64 0.00 154.64 2.50 152.14 8,735.38 8,583.24

Water-Level Measurements  39
40 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase I wells—Continued

SC–3B 06/06/03 Access hole in cap 154.61 0.00 154.61 2.50 152.11 8,735.38 8,583.27

SC–3B 07/09/03 Access hole in cap 154.94 0.00 154.94 2.50 152.44 8,735.38 8,582.94

SC–3B 08/21/03 Access hole in cap 155.10 0.00 155.10 2.50 152.60 8,735.38 8,582.78

SC–3B 09/18/03 Access hole in cap 154.97 0.00 154.97 2.50 152.47 8,735.38 8,582.91

SC–3B 10/20/03 Access hole in cap 154.62 0.00 154.62 2.50 152.12 8,735.38 8,583.26

SC–3B 10/21/03 Access hole in cap 154.71 0.00 154.71 2.50 152.21 8,735.38 8,583.17

SC–3B 12/05/03 Access hole in cap 154.68 0.00 154.68 2.50 152.18 8,735.38 8,583.20

SC–3B 02/20/04 Access hole in cap 154.22 0.00 154.22 2.50 151.72 8,735.38 8,583.66

SC–3B 03/25/04 Access hole in cap 153.99 0.00 153.99 2.50 151.49 8,735.38 8,583.89

SC–3B 05/12/04 Access hole in cap 152.03 0.00 152.03 1.50 150.53 8,735.38 8,584.85

SC–3B 06/01/04 Access hole in cap 152.39 0.00 152.39 2.50 149.89 8,735.38 8,585.49

SC–4A 03/15/02 Top of casing 76.54 +0.12 76.42 2.21 74.22 8,745.70 8,671.49

SC–4A 03/19/02 Top of casing 76.96 +0.12 76.84 2.21 74.63 8,745.70 8,671.07

SC–4A 03/25/02 Access hole in cap 77.69 0.00 77.69 2.21 75.48 8,745.70 8,670.22

SC–4A 04/24/02 Access hole in cap 78.37 0.00 78.37 2.21 76.17 8,745.70 8,669.54

SC–4A 05/23/02 Access hole in cap 78.75 0.00 78.75 2.21 76.55 8,745.70 8,669.16

SC–4A 06/25/02 Access hole in cap 79.08 0.00 79.08 2.21 76.88 8,745.70 8,668.83

SC–4A 07/25/02 Access hole in cap 79.18 0.00 79.18 2.21 76.98 8,745.70 8,668.73

SC–4A 08/21/02 Access hole in cap 79.10 0.00 79.10 2.21 76.89 8,745.70 8,668.81

SC–4A 09/18/02 Access hole in cap 78.76 0.00 78.76 2.21 76.56 8,745.70 8,669.15

SC–4A 10/17/02 Access hole in cap 74.90 0.00 74.90 2.21 72.70 8,745.70 8,673.01

SC–4A 11/14/02 Access hole in cap 76.54 0.00 76.54 2.21 74.34 8,745.70 8,671.37

SC–4A 12/13/02 Access hole in cap 76.68 0.00 76.68 2.21 74.48 8,745.70 8,671.23

SC–4A 02/08/03 Access hole in cap 78.17 0.00 78.17 2.21 75.97 8,745.70 8,669.74

SC–4A 04/15/03 Access hole in cap 74.20 0.00 74.20 2.21 72.00 8,745.70 8,673.71

SC–4A 05/14/03 Access hole in cap 74.02 0.00 74.02 2.21 71.81 8,745.70 8,673.89

SC–4A 06/03/03 Top of casing 75.94 +0.12 75.82 2.21 73.61 8,745.70 8,672.09

SC–4A 06/05/03 Access hole in cap 76.15 0.00 76.15 2.21 73.95 8,745.70 8,671.76

SC–4A 06/06/03 Access hole in cap 76.23 0.00 76.23 2.21 74.03 8,745.70 8,671.68
Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase I wells—Continued

SC–4A 07/09/03 Access hole in cap 77.77 0.00 77.77 2.21 75.56 8,745.70 8,670.14

SC–4A 08/21/03 Access hole in cap 78.34 0.00 78.34 2.21 76.14 8,745.70 8,669.57

SC–4A 09/18/03 Access hole in cap 77.91 0.00 77.91 2.21 75.70 8,745.70 8,670.00

SC–4A 10/20/03 Access hole in cap 77.02 0.00 77.02 2.21 74.81 8,745.70 8,670.89

SC–4A 10/21/03 Access hole in cap 77.03 0.00 77.03 2.21 74.83 8,745.70 8,670.88

SC–4A 12/05/03 Access hole in cap 78.17 0.00 78.17 2.21 75.97 8,745.70 8,669.74

SC–4A 02/20/04 Access hole in cap 78.79 0.00 78.79 2.21 76.58 8,745.70 8,669.12

SC–4A 05/12/04 Access hole in cap 73.28 0.00 73.28 2.21 71.08 8,745.70 8,674.63

SC–4A 05/12/04 Access hole in cap 73.28 0.00 73.28 2.21 71.08 8,745.70 8,674.63

SC–5A 03/15/02 Top of casing 154.41 +0.12 154.29 2.63 151.66 8,559.29 8,407.64

SC–5A 03/19/02 Top of casing 154.49 +0.12 154.37 2.63 151.74 8,559.29 8,407.55

SC–5A 03/27/02 Access hole in cap 154.35 0.00 154.35 2.63 151.72 8,559.29 8,407.57

SC–5A 04/26/02 Access hole in cap 151.55 0.00 151.55 2.63 148.92 8,559.29 8,410.37

SC–5A 05/23/02 Access hole in cap 150.43 0.00 150.43 2.63 147.80 8,559.29 8,411.49

SC–5A 06/26/02 Access hole in cap 152.03 0.00 152.03 2.63 149.40 8,559.29 8,409.89

SC–5A 07/23/02 Access hole in cap 153.91 0.00 153.91 2.63 151.28 8,559.29 8,408.01

SC–5A 08/22/02 Access hole in cap 156.29 0.00 156.29 2.63 153.66 8,559.29 8,405.63

SC–5A 09/17/02 Access hole in cap 157.00 0.00 157.00 2.63 154.37 8,559.29 8,404.92

SC–5A 10/16/02 Access hole in cap 157.55 0.00 157.55 2.63 154.92 8,559.29 8,404.37

SC–5A 11/14/02 Access hole in cap 157.98 0.00 157.98 2.63 155.35 8,559.29 8,403.94

SC–5A 12/13/02 Access hole in cap 157.31 0.00 157.31 2.63 154.68 8,559.29 8,404.61

SC–5A 02/08/03 Access hole in cap 156.39 0.00 156.39 2.63 153.76 8,559.29 8,405.53

SC–5A 04/15/03 Access hole in cap 154.78 0.00 154.78 2.63 152.15 8,559.29 8,407.14

SC–5A 05/13/03 Access hole in cap 145.06 0.00 145.06 2.63 142.43 8,559.29 8,416.86

SC–5A 06/04/03 Top of casing 138.13 +0.12 138.01 2.63 135.38 8,559.29 8,423.91

SC–5A 06/05/03 Access hole in cap 137.98 0.00 137.98 2.63 135.35 8,559.29 8,423.94

SC–5A 06/06/03 Access hole in cap 137.97 0.00 137.97 2.63 135.34 8,559.29 8,423.95

SC–5A 07/08/03 Access hole in cap 140.18 0.00 140.18 2.63 137.55 8,559.29 8,421.74

SC–5A 08/20/03 Access hole in cap 146.42 0.00 146.42 2.63 143.79 8,559.29 8,415.50

SC–5A 09/18/03 Access hole in cap 148.53 0.00 148.53 2.63 145.90 8,559.29 8,413.39

Water-Level Measurements 41
42 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase I wells—Continued

SC–5A 10/20/03 Access hole in cap 151.38 0.00 151.38 2.63 148.75 8,559.29 8,410.54

SC–5A 11/22/03 Access hole in cap 152.74 0.00 152.74 2.63 150.11 8,559.29 8,409.18

SC–5A 12/01/03 Access hole in cap 150.77 0.00 150.77 2.63 148.14 8,559.29 8,411.15

SC–5A 12/02/03 Access hole in cap 150.22 0.00 150.22 2.63 147.59 8,559.29 8,411.70

SC–5A 12/03/03 Access hole in cap 149.96 0.00 149.96 2.63 147.33 8,559.29 8,411.96

SC–5A 03/25/04 Access hole in cap 153.14 0.00 153.14 2.63 150.51 8,559.29 8,408.78

SC–5A 05/12/04 Access hole in cap 141.60 0.00 141.60 2.63 138.97 8,559.29 8,420.32

SC–5A 06/04/04 Access hole in cap 136.83 0.00 136.83 2.63 134.20 8,559.29 8,425.09

SC–5B 03/19/02 Top of casing 153.27 0.00 153.27 3.00 150.27 8,558.02 8,407.75

SC–5B 03/27/02 Access hole in cap 152.66 0.00 152.66 3.00 149.66 8,558.02 8,408.36

SC–5B 04/26/02 Access hole in cap 149.01 0.00 149.01 3.00 146.01 8,558.02 8,412.01

SC–5B 05/23/02 Access hole in cap 148.78 0.00 148.78 3.00 145.78 8,558.02 8,412.24

SC–5B 06/26/02 Access hole in cap 150.38 0.00 150.38 3.00 147.38 8,558.02 8,410.64

SC–5B 07/23/02 Access hole in cap 152.22 0.00 152.22 3.00 149.22 8,558.02 8,408.80

SC–5B 08/22/02 Access hole in cap 155.65 0.00 155.65 3.00 152.65 8,558.02 8,405.37

SC–5B 09/17/02 Access hole in cap 156.08 0.00 156.08 3.00 153.08 8,558.02 8,404.94

SC–5B 10/16/02 Access hole in cap 155.81 0.00 155.81 3.00 152.81 8,558.02 8,405.21

SC–5B 11/14/02 Access hole in cap 156.33 0.00 156.33 3.00 153.33 8,558.02 8,404.69

SC–5B 12/13/02 Access hole in cap 155.49 0.00 155.49 3.00 152.49 8,558.02 8,405.53

SC–5B 02/08/03 Access hole in cap 154.72 0.00 154.72 3.00 151.72 8,558.02 8,406.30

SC–5B 04/15/03 Access hole in cap 153.00 0.00 153.00 3.00 150.00 8,558.02 8,408.02

SC–5B 05/13/03 Access hole in cap 143.52 0.00 143.52 3.00 140.52 8,558.02 8,417.50

SC–5B 06/04/03 Top of casing 136.28 0.00 136.28 3.00 133.28 8,558.02 8,424.74

SC–5B 06/05/03 Access hole in cap 136.37 0.00 136.37 3.00 133.37 8,558.02 8,424.65

SC–5B 06/06/03 Access hole in cap 136.17 0.00 136.17 3.00 133.17 8,558.02 8,424.85

SC–5B 07/08/03 Access hole in cap 138.42 0.00 138.42 3.00 135.42 8,558.02 8,422.60

SC–5B 08/20/03 Access hole in cap 144.80 0.00 144.80 3.00 141.80 8,558.02 8,416.22

SC–5B 09/18/03 Access hole in cap 146.89 0.00 146.89 3.00 143.89 8,558.02 8,414.13

SC–5B 10/20/03 Access hole in cap 149.78 0.00 149.78 3.00 146.78 8,558.02 8,411.24

SC–5B 10/24/03 Access hole in cap 150.91 0.00 150.91 3.00 147.91 8,558.02 8,410.11
Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase I wells—Continued

SC–5B 11/22/03 Access hole in cap 151.00 0.00 151.00 3.00 148.00 8,558.02 8,410.02

SC–5B 12/01/03 Access hole in cap 148.89 0.00 148.89 3.00 145.89 8,558.02 8,412.13

SC–5B 12/02/03 Access hole in cap 148.36 0.00 148.36 3.00 145.36 8,558.02 8,412.66

SC–5B 12/03/03 Access hole in cap 148.26 0.00 148.26 3.00 145.26 8,558.02 8,412.76

SC–5B 03/25/04 Access hole in cap 151.52 0.00 151.52 3.00 148.52 8,558.02 8,409.50

SC–5B 05/12/04 Access hole in cap 139.78 0.00 139.78 3.00 136.78 8,558.02 8,421.24

SC–5B 06/01/04 Access hole in cap 135.21 0.00 135.21 3.00 132.21 8,558.02 8,425.81

Phase II wells

Hottentot 02/05/03 Access hole in cap 100.10 0.00 100.10 1.38 98.72 8,790.79 8,692.07

Hottentot 05/12/03 Access hole in cap 98.41 0.00 98.41 1.38 97.03 8,790.79 8,693.76

Hottentot 07/09/03 Access hole in cap 99.09 0.00 99.09 1.38 97.71 8,790.79 8,693.08

Hottentot 08/20/03 Access hole in cap 99.39 0.00 99.39 1.38 98.01 8,790.79 8,692.78

Hottentot 09/18/03 Access hole in cap 99.26 0.00 99.26 1.38 97.88 8,790.79 8,692.91

Hottentot 10/24/03 Access hole in cap 98.94 0.00 98.94 1.38 97.56 8,790.79 8,693.23

Hottentot 12/05/03 Access hole in cap 99.41 0.00 99.41 1.38 98.03 8,790.79 8,692.76

Hottentot 03/26/04 Access hole in cap 99.18 0.00 99.18 1.38 97.80 8,790.79 8,692.99

Hottentot 05/12/04 Access hole in cap 96.38 0.00 96.38 1.38 95.00 8,790.79 8,695.79

Hottentot 06/01/04 Access hole in cap 96.50 0.00 96.50 1.38 95.12 8,790.79 8,695.67

SC–6A 02/07/03 Access hole in cap 136.20 0.00 136.20 3.08 133.12 8,739.43 8,606.31

SC–6A 04/15/03 Access hole in cap 134.32 0.00 134.32 3.08 131.24 8,739.43 8,608.19

SC–6A 05/14/03 Access hole in cap 134.89 0.00 134.89 3.08 131.81 8,739.43 8,607.62

SC–6A 06/03/03 Top of casing 135.45 +0.12 135.33 3.08 132.25 8,739.43 8,607.18

SC–6A 06/06/03 Access hole in cap 135.57 0.00 135.57 3.08 132.49 8,739.43 8,606.94

SC–6A 07/09/03 Access hole in cap 135.71 0.00 135.71 3.08 132.63 8,739.43 8,606.80

SC–6A 08/18/03 Access hole in cap 135.79 0.00 135.79 3.08 132.71 8,739.43 8,606.72

SC–6A 09/18/03 Access hole in cap 135.81 0.00 135.81 3.08 132.73 8,739.43 8,606.70

SC–6A 10/20/03 Access hole in cap 135.67 0.00 135.67 3.08 132.59 8,739.43 8,606.84

SC–6A 10/21/03 Access hole in cap 135.68 0.00 135.68 3.08 132.60 8,739.43 8,606.83

SC–6A 10/30/03 Access hole in cap 135.71 0.00 135.71 3.08 132.63 8,739.43 8,606.80

SC–6A 12/05/03 Access hole in cap 136.05 0.00 136.05 3.08 132.97 8,739.43 8,606.46

Water-Level Measurements 43
44 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase II wells—Continued

SC–6A 02/20/04 Access hole in cap 136.05 0.00 136.05 3.08 132.97 8,739.43 8,606.46

SC–6A 03/25/04 Access hole in cap 135.56 0.00 135.56 3.08 132.48 8,739.43 8,606.95

SC–6A 05/12/04 Access hole in cap 134.20 0.00 134.20 3.08 131.12 8,739.43 8,608.31

SC–6A 06/01/04 Access hole in cap 135.21 0.00 135.21 3.08 132.13 8,739.43 8,607.30

SC–7A 02/04/03 Access hole in cap 111.71 0.00 111.71 3.63 108.08 8,506.86 8,398.78

SC–7A 04/17/03 Access hole in cap 109.19 0.00 109.19 3.63 105.56 8,506.86 8,401.30

SC–7A 05/12/03 Access hole in cap 101.06 0.00 101.06 3.63 97.43 8,506.86 8,409.43

SC–7A 06/05/03 Top of casing 95.60 +0.12 95.48 3.63 91.85 8,506.86 8,415.01

SC–7A 07/08/03 Access hole in cap 97.71 0.00 97.71 3.63 94.08 8,506.86 8,412.78

SC–7A 08/18/03 Access hole in cap 102.52 0.00 102.52 3.63 98.89 8,506.86 8,407.97

SC–7A 09/18/03 Access hole in cap 104.51 0.00 104.51 3.63 100.88 8,506.86 8,405.98

SC–7A 10/06/03 Access hole in cap 106.27 0.00 106.27 3.63 102.64 8,506.86 8,404.22

SC–7A 10/24/03 Access hole in cap 107.45 0.00 107.45 3.63 103.82 8,506.86 8,403.04

SC–7A 10/31/03 Access hole in cap 107.45 0.00 107.45 3.63 103.82 8,506.86 8,403.04

SC–7A 11/22/03 Access hole in cap 108.14 0.00 108.14 3.63 104.51 8,506.86 8,402.35

SC–7A 12/01/03 Top of casing 106.89 -0.02 106.91 3.63 103.28 8,506.86 8,403.58

SC–7A 12/03/03 Top of casing 106.39 -0.02 106.41 3.63 102.78 8,506.86 8,404.08

SC–7A 02/20/04 Top of casing 108.48 -0.02 108.50 3.63 104.87 8,506.86 8,401.99

SC–7A 03/26/04 Top of casing 108.17 -0.02 108.19 3.63 104.56 8,506.86 8,402.30

SC–7A 05/11/04 Top of casing 98.10 -0.02 98.12 3.63 94.49 8,506.86 8,412.37

SC–7A 06/01/04 Top of casing 94.17 -0.02 94.19 3.63 90.56 8,506.86 8,416.30

SC–8A 02/08/03 Access hole in cap 73.01 0.00 73.01 3.17 69.84 8,468.22 8,398.38

SC–8A 04/17/03 Access hole in cap 70.34 0.00 70.34 3.17 67.17 8,468.22 8,401.05

SC–8A 05/12/03 Access hole in cap 62.38 0.00 62.38 3.17 59.21 8,468.22 8,409.01

SC–8A 06/05/03 Top of casing 57.44 +0.12 57.32 3.17 54.15 8,468.22 8,414.07

SC–8A 07/08/03 Top of casing 59.46 +0.12 59.34 3.17 56.17 8,468.22 8,412.05

SC–8A 08/18/03 Access hole in cap 64.08 0.00 64.08 3.17 60.91 8,468.22 8,407.31

SC–8A 09/18/03 Access hole in cap 65.97 0.00 65.97 3.17 62.80 8,468.22 8,405.42

SC–8A 10/06/03 Access hole in cap 67.86 0.00 67.86 3.17 64.69 8,468.22 8,403.53

SC–8A 10/23/03 Access hole in cap 68.88 0.00 68.88 3.17 65.71 8,468.22 8,402.51
Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase II wells—Continued

SC–8A 10/31/03 Access hole in cap 68.82 0.00 68.82 3.17 65.65 8,468.22 8,402.57

SC–8A 11/22/03 Access hole in cap 69.62 0.00 69.62 3.17 66.45 8,468.22 8,401.77

SC–8A 12/01/03 Top of casing 68.39 +0.12 68.27 3.17 65.10 8,468.22 8,403.12

SC–8A 12/02/03 Top of casing 67.85 +0.12 67.73 3.17 64.56 8,468.22 8,403.66

SC–8A 12/03/03 Top of casing 67.98 +0.12 67.86 3.17 64.69 8,468.22 8,403.53

SC–8A 02/20/04 Top of casing 69.81 +0.12 69.69 3.17 66.52 8,468.22 8,401.70

SC–8A 03/26/04 Top of casing 69.49 +0.12 69.37 3.17 66.20 8,468.22 8,402.02

SC–8A 05/11/04 Top of casing 59.52 +0.12 59.40 3.17 56.23 8,468.22 8,411.99

SC–8A 05/12/04 Top of casing 59.06 +0.12 58.94 3.17 55.77 8,468.22 8,412.45

SC–8A 06/01/04 Top of casing 55.93 +0.12 55.81 3.17 52.64 8,468.22 8,415.58

SC–9A 03/26/04 Top of casing 219.76 0.00 318.38 1.79 316.59 8444.19 8,427.60

SC–9A 05/12/04 Top of casing 219.64 0.00 318.26 1.79 316.47 8444.19 8,427.72

SC–9A 06/01/04 Top of casing 219.76 0.00 318.38 1.79 316.59 8444.19 8,427.60

Hansen 02/05/03 Access hole in cap 107.91 0.00 107.91 3.23 104.68 8,569.53 8,464.85

Hansen 04/17/03 Top of casing 103.93 -0.02 103.95 3.23 100.72 8,569.53 8,468.81

Hansen 05/13/03 Access hole in cap 107.35 0.00 107.35 3.23 104.12 8,569.53 8,465.41

Hansen 07/09/03 Top of casing 107.92 -0.02 107.94 3.23 104.71 8,569.53 8,464.82

Hansen 08/19/03 Access hole in cap 107.84 0.00 107.84 3.23 104.61 8,569.53 8,464.92

Hansen 09/18/03 Top of casing 107.00 -0.02 107.02 3.23 103.79 8,569.53 8,465.74

Hansen 10/21/03 Access hole in cap 107.73 0.00 107.73 3.23 104.50 8,569.53 8,465.03

Hansen 12/05/03 Top of casing 107.96 -0.02 107.98 3.23 104.75 8,569.53 8,464.78

Hansen 02/20/04 Top of casing 107.72 -0.02 107.74 3.23 104.51 8,569.53 8,465.02

Hansen 03/26/04 Top of casing 106.70 -0.02 106.72 3.23 103.49 8,569.53 8,466.04

Hansen 05/11/04 Top of casing 104.89 -0.02 104.91 3.23 101.68 8,569.53 8,467.85

Hansen 06/01/04 Top of casing 107.68 -0.02 107.70 3.23 104.47 8,569.53 8,465.06

La Bobita 02/07/03 Access hole in cap 64.37 0.00 64.37 3.23 61.14 8,229.45 8,168.31

La Bobita 04/17/03 Top of casing 60.92 -0.02 60.94 3.23 57.71 8,229.45 8,171.74

La Bobita 05/15/03 Access hole in cap 58.88 0.00 58.88 3.23 55.65 8,229.45 8,173.80

La Bobita 07/08/03 Top of casing 59.99 -0.02 60.01 3.23 56.78 8,229.45 8,172.67

La Bobita 08/18/03 Access hole in cap 62.05 0.00 62.05 3.23 58.82 8,229.45 8,170.63

Water-Level Measurements 45
46  Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase II wells—Continued

La Bobita 09/18/03 Top of casing 61.04 -0.02 61.06 3.23 57.83 8,229.45 8,171.62

La Bobita 10/23/03 Access hole in cap 61.84 0.00 61.84 3.23 58.61 8,229.45 8,170.84

La Bobita 12/05/03 Top of casing 61.82 -0.02 61.84 3.23 58.61 8,229.45 8,170.84

La Bobita 02/19/04 Top of casing 62.77 -0.02 62.79 3.23 59.56 8,229.45 8,169.89

La Bobita 03/26/04 Top of casing 63.43 -0.02 63.45 3.23 60.22 8,229.45 8,169.23

La Bobita 05/11/04 Top of casing 58.91 -0.02 58.93 3.23 55.70 8,229.45 8,173.75

La Bobita 05/12/04 Top of casing 58.85 -0.02 58.87 3.23 55.64 8,229.45 8,173.81

La Bobita 05/13/04 Top of casing 58.75 -0.02 58.77 3.23 55.54 8,229.45 8,173.91

La Bobita 06/02/04 Top of casing 59.38 -0.02 59.40 3.23 56.17 8,229.45 8,173.28

CC–1A 02/04/03 Top of casing 5.90 0.00 5.90 2.50 3.40 8,880.23 8,876.83

CC–1A 04/10/03 Top of casing 4.92 0.00 4.92 2.50 2.42 8,880.23 8,877.81

CC–1A 05/07/03 Top of casing 6.84 0.00 6.84 2.50 4.34 8,880.23 8,875.89

CC–1A 05/14/03 Top of casing 7.58 0.00 7.58 2.50 5.08 8,880.23 8,875.15

CC–1A 06/04/03 Top of casing 10.04 0.00 10.04 2.50 7.54 8,880.23 8,872.69

CC–1A 07/21/03 Top of casing 12.00 0.00 12.00 2.50 9.50 8,880.23 8,870.73

CC–1A 08/12/03 Top of casing 10.76 0.00 10.76 2.50 8.26 8,880.23 8,871.97

CC–1A 09/11/03 Top of casing 7.95 0.00 7.95 2.50 5.45 8,880.23 8,874.78

CC–1A 10/22/03 Top of casing 9.26 0.00 9.26 2.50 6.76 8,880.23 8,873.47

CC–1A 10/23/03 Top of casing 9.50 0.00 9.50 2.50 7.00 8,880.23 8,873.23

CC–1A 11/04/03 Top of casing 9.13 0.00 9.13 2.50 6.63 8,880.23 8,873.60

CC–1A 12/11/03 Top of casing 8.33 0.00 8.33 2.50 5.83 8,880.23 8,874.40

CC–1A 01/07/04 Top of casing 8.28 0.00 8.28 2.50 5.78 8,880.23 8,874.45

CC–1A 04/21/04 Top of casing 5.71 0.00 5.71 2.50 3.21 8,880.23 8,877.02

CC–1B 02/05/03 Access hole in cap 10.50 0.00 10.50 2.96 7.54 8,878.31 8,870.77

CC–1B 03/04/03 Access hole in cap 9.99 0 9.99 2.96 7.03 8,878.31 8,871.28

CC–1B 04/10/03 Access hole in cap 8.77 0 8.77 2.96 5.81 8,878.31 8,872.50

CC–1B 05/06/03 Access hole in cap 9.83 0 9.83 2.96 6.87 8,878.31 8,871.44

CC–1B 06/04/03 Access hole in cap 11.86 0.00 11.86 2.96 8.90 8,878.31 8,869.41

CC–1B 07/21/03 Access hole in cap 12.74 0.00 12.74 2.96 9.78 8,878.31 8,868.53

CC–1B 08/12/03 Access hole in cap 12.01 0.00 12.01 2.96 9.05 8,878.31 8,869.26
Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase II wells—Continued

CC–1B 08/19/03 Access hole in cap 12.24 0.00 12.24 2.96 9.28 8,878.31 8,869.03

CC–1B 09/11/03 Access hole in cap 10.22 0.00 10.22 2.96 7.26 8,878.31 8,871.05

CC–1B 10/22/03 Access hole in cap 11.38 0.00 11.38 2.96 8.42 8,878.31 8,869.89

CC–1B 10/23/03 Access hole in cap 11.65 0.00 11.65 2.96 8.69 8,878.31 8,869.62

CC–1B 11/04/03 Access hole in cap 11.39 0.00 11.39 2.96 8.43 8,878.31 8,869.88

CC–1B 12/11/03 Access hole in cap 10.65 0.00 10.65 2.96 7.69 8,878.31 8,870.62

CC–1B 01/07/04 Access hole in cap 10.58 0.00 10.58 2.96 7.62 8,878.31 8,870.69

CC–1B 04/21/04 Access hole in cap 9.45 0.00 9.45 2.96 6.49 8,878.31 8,871.82

CC–2A 04/10/03 Top of casing 8.42 0.00 8.42 4.00 4.42 8,876.02 8,871.60

CC–2A 05/06/03 Top of casing 8.34 0.00 8.34 4.00 4.34 8,876.02 8,871.68

CC–2A 05/14/03 Top of casing 8.76 0.00 8.76 4.00 4.76 8,876.02 8,871.26

CC–2A 06/04/03 Top of casing 9.40 0.00 9.40 4.00 5.40 8,876.02 8,870.62

CC–2A 07/21/03 Top of casing 12.00 0.00 12.00 4.00 8.00 8,876.02 8,868.02

CC–2A 08/12/03 Top of casing 9.50 0.00 9.50 4.00 5.50 8,876.02 8,870.52

CC–2A 08/19/03 Top of casing 9.54 0.00 9.54 4.00 5.54 8,876.02 8,870.48

CC–2A 09/11/03 Top of casing 7.45 0 7.45 4.00 3.45 8,876.02 8,872.57

CC–2A 10/22/03 Top of casing 9.21 0.00 9.21 4.00 5.21 8,876.02 8,870.81

CC–2A 10/23/03 Top of casing 9.30 0.00 9.30 4.00 5.30 8,876.02 8,870.72

CC–2A 11/04/03 Top of casing 9.26 0.00 9.26 4.00 5.26 8,876.02 8,870.76

CC–2A 12/11/03 Top of casing 9.32 0.00 9.32 4.00 5.32 8,876.02 8,870.70

CC–2A 01/07/04 Top of casing 9.45 0.00 9.45 4.00 5.45 8,876.02 8,870.57

CC–2A 02/25/04 Top of casing 9.32 0.00 9.32 4.00 5.32 8,876.02 8,870.70

CC–2A 04/21/04 Top of casing 7.94 0.00 7.94 4.00 3.94 8,876.02 8,872.08

CC–2B 02/05/03 Access hole in cap 10.87 0.00 10.87 2.21 8.66 8,877.53 8,868.87

CC–2B 03/04/03 Access hole in cap 9.68 0.00 9.68 2.21 7.47 8,877.53 8,870.06

CC–2B 04/10/03 Access hole in cap 8.63 0.00 8.63 2.21 6.42 8,877.53 8,871.11

CC–2B 05/06/03 Access hole in cap 10.00 0.00 10.00 2.21 7.79 8,877.53 8,869.74

CC–2B 06/04/03 Access hole in cap 9.12 0.00 9.12 2.21 6.91 8,877.53 8,870.62

CC–2B 07/21/03 Access hole in cap 10.15 0.00 10.15 2.21 7.94 8,877.53 8,869.59

CC–2B 08/12/03 Access hole in cap 9.87 0.00 9.87 2.21 7.66 8,877.53 8,869.87

Water-Level Measurements 47
48  Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Phase II wells—Continued

CC–2B 08/19/03 Access hole in cap 9.87 0.00 9.87 2.21 7.66 8,877.53 8,869.87

CC–2B 09/11/03 Access hole in cap 9.19 0.00 9.19 2.21 6.98 8,877.53 8,870.55

CC–2B 10/22/03 Access hole in cap 9.48 0.00 9.48 2.21 7.27 8,877.53 8,870.26

CC–2B 10/23/03 Access hole in cap 10.77 0.00 10.77 2.21 8.56 8,877.53 8,868.97

CC–2B 11/04/03 Access hole in cap 9.55 0.00 9.55 2.21 7.34 8,877.53 8,870.19

CC–2B 12/11/03 Access hole in cap 9.60 0.00 9.60 2.21 7.39 8,877.53 8,870.14

CC–2B 01/07/04 Access hole in cap 9.70 0.00 9.70 2.21 7.49 8,877.53 8,870.04

CC–2B 04/21/04 Access hole in cap 8.41 0.00 8.41 2.21 6.20 8,877.53 8,871.33

Existing Advanced Wastewater Treatment Facility wells

AWWT–1 03/27/02 Top of casing 124.68 0.00 124.68 0.50 124.18 8,523.00 8,398.82

AWWT–1 04/26/02 Top of casing 121.95 0.00 121.95 0.50 121.45 8,523.00 8,401.55

AWWT–1 05/23/02 Top of casing 121.26 0.00 121.26 0.50 120.76 8,523.00 8,402.24

AWWT–1 06/26/02 Top of casing 123.20 0.00 123.20 0.50 122.70 8,523.00 8,400.30

AWWT–1 07/26/02 Top of casing 125.10 0.00 125.10 0.50 124.60 8,523.00 8,398.40

AWWT–1 08/22/02 Top of casing 127.22 0.00 127.22 0.50 126.72 8,523.00 8,396.28

AWWT–1 09/17/02 Top of casing 128.40 0.00 128.40 0.50 127.90 8,523.00 8,395.10

AWWT–1 10/17/02 Top of casing 128.29 0.00 128.29 0.50 127.79 8,523.00 8,395.21

AWWT–1 12/11/02 Top of casing 128.42 0.00 128.42 0.50 127.92 8,523.00 8,395.08

AWWT–1 02/04/03 Top of casing 127.30 0.00 127.30 0.50 126.80 8,523.00 8,396.20

AWWT–1 04/17/03 Top of casing 124.85 0.00 124.85 0.50 124.35 8,523.00 8,398.65

AWWT–1 05/12/03 Top of casing 116.54 0.00 116.54 0.50 116.04 8,523.00 8,406.96

AWWT–1 07/08/03 Top of casing 113.02 0.00 113.02 0.50 112.52 8,523.00 8,410.48

AWWT–1 08/21/03 Top of casing 118.37 0.00 118.37 0.50 117.87 8,523.00 8,405.13

AWWT–1 09/18/03 Top of casing 120.04 0.00 120.04 0.50 119.54 8,523.00 8,403.46

AWWT–1 10/06/03 Top of casing 121.77 0.00 121.77 0.50 121.27 8,523.00 8,401.73

AWWT–1 10/24/03 Top of casing 123.50 0.00 123.50 0.50 123.00 8,523.00 8,400.00

AWWT–1 10/31/03 Top of casing 123.00 0.00 123.00 0.50 122.50 8,523.00 8,400.50

AWWT–1 11/22/03 Top of casing 123.70 0.00 123.70 0.50 123.20 8,523.00 8,456.80

AWWT–1 12/01/03 Top of casing 122.57 0.00 122.57 0.50 122.07 8,523.00 8,400.93

AWWT–1 12/03/03 Top of casing 121.98 0.00 121.98 0.50 121.48 8,523.00 8,401.52
Table 4. Altitude of water levels in Phase I and II wells and existing Advanced Wastewater Treatment Facility wells, Red River Valley, 

north-central New Mexico, 2002–04.—Continued 

[Shaded rows indicate water-level measurements obtained by URS, Denver, Colorado. NGVD 29, National Geodetic Vertical Datum of 1929]

Well 

identification

(figs. 2–5)

Date

(month/

day/year)

 Measuring point 

(permanent 

measuring point if 

no correction)

Depth to 

water 

(feet below 

measuring 

point)

Measuring point 

correction 

(feet)1

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land 

surface)

Land 

surface 

altitude 

(feet above 

NGVD 29)

Altitude 

of water 

level (feet 

above 

NGVD 29)

Existing Advanced Wastewater Treatment Facility wells—Continued

AWWT–1 02/20/04 Top of casing 124.04 0.00 124.04 0.50 123.54 8,523.00 8,399.46

AWWT–1 03/26/04 Top of casing 123.86 0.00 123.86 0.50 123.36 8,523.00 8,399.64

AWWT–1 05/11/04 Top of casing 113.61 0.00 113.61 0.50 113.11 8,523.00 8,409.89

AWWT–1 06/01/04 Top of casing 109.61 0.00 109.61 0.50 109.11 8,523.00 8,413.89

AWWT–2 12/13/02 Top of casing 108.64 0.00 108.64 1.17 107.47 8,560.00 8,452.53

AWWT–2 10/06/03 Top of casing 100.90 0.00 100.90 1.17 99.73 8,560.00 8,460.27

AWWT–2 10/24/03 Access hole in cap 102.94 +0.03 102.91 1.17 101.74 8,560.00 8,458.26

AWWT–2 10/31/03 Access hole in cap 103.89 +0.03 103.86 1.17 102.69 8,560.00 8,457.31

AWWT–2 11/22/03 Access hole in cap 103.68 +0.03 103.65 1.17 102.48 8,560.00 8,457.52

AWWT–2 12/01/03 Top of casing 104.36 0.00 104.36 1.17 103.19 8,560.00 8,456.81

AWWT–2 12/02/03 Top of casing 104.28 0.00 104.28 1.17 103.11 8,560.00 8,456.89

AWWT–2 12/03/03 Top of casing 104.39 0.00 104.39 1.17 103.22 8,560.00 8,456.78

1

Measuring point correction is distance of measuring point at time of measurement, in feet above (+) or below (-) permanent measuring point.

2

Depth is measured along the well bore. Well bore was angled 21.5 degrees from vertical.

3

Calculated vertical distance from measuring point or land surface to water.

Wells 2–1 and 2–2 were installed about 450 ft upstream 

(east) from a line from the Red River to the La Bobita well 

(fig. 4). Well 2–1 is adjacent to the north bank of the Red 

River, and well 2–2 is about 100 ft farther north of the Red 

River. Wells 2–1 and 2–2 were advanced to 15.97 and 14.37 ft 

below land surface, respectively, at which depth a 

semiconsolidated deposit (possibly ferricrete) was encountered 

and no further advancement was achieved. 

Ground-water levels in wells 2–1 and 2–2 ranged from 

30.35 to 35.11 ft higher than concurrently measured water levels in well 1 (table 5). The land surface at wells 2–1 and 2–2 is 

about 20.6 ft higher than at well 1 (table 5). The substantially 

higher water levels in wells 2–1 and 2–2 relative to those measured concurrently in the La Bobita well and well 1 indicate 

that the underlying semiconsolidated deposits encountered at 

total depths of wells 2–1 and 2–2 are substantially less permeable than the overlying alluvium. Therefore, ground water near 

wells 2–1 and 2–2 is perched by the semiconsolidated deposits 

encountered during drilling. Water in wells 2–1 and 2–2 may 

be disconnected from or have a poor hydraulic connection to 

ground water present at the La Bobita well and well 1. 

Ground-water levels were measured in wells 2–1 and 2–2 

in May and June 2004. The stage of the Red River also was 

measured where a line approximately perpendicular to the 

bank of the river intersects wells 2–1 and 2–2. Ground-water 

levels in well 2–1 ranged from about 0.2 to 0.7 ft higher than 

the stage of the Red River (fig. 14, table 5). Ground-water levels in well 2–2 ranged from about 0.4 to 0.1 ft lower than the 

stage of the Red River (fig. 14, table 5). Ground-water levels 

in well 2–1 were 0.59 and 0.80 ft higher than those in 

well 2–2. Differences of less than 1 ft between water levels 

in wells 2–1, 2–2, and the stage of the Red River indicate 

that there is a substantial hydraulic connection between the 

ground-water system penetrated by the wells and the Red 

River surface-water system. 

Well 3 was installed about 1,600 ft upstream (east) from 

wells 2–1 and 2–2 (fig. 4). Ground-water levels measured in 

well 3 in May and June 2004 ranged from 0.5 to 1.1 ft higher 

than the stage of the Red River where a line approximately 

perpendicular to the bank of the river intersects well 3. These 

water-level measurements indicate that the Red River and the 

underlying ground water are hydraulically connected and that 

ground water has a gradient toward the Red River.

Water-Level Measurements 49
50 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Table 5. Altitude of water levels in La Bobita and Phase III wells and concurrent altitude of stage of Red River, northcentral New Mexico, 2003–04.

[Permanent measuring point for Phase III wells is top of the 1-inch PVC casing (TOC); NGVD 29, National Geodetic Vertical Datum of 1929; --, no data]

Well 

identification

(fig. 4)

Date

(month/day/

year)

Land-surface 

altitude 

(feet above 

NGVD 29)

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land surface)

Water-level 

altitude 

(feet above 

NGVD 29)

Altitude of 

Red River 

stage 

(feet above 

NGVD 29)

Water-level 

altitude in 

well minus 

altitude of 

Red River 

stage 

(feet)

La Bobita 12/05/03 8,229.45 61.84 3.23 58.61 8,170.84 -- --

La Bobita 02/19/04 8,229.45 62.79 3.23 59.56 8,169.89 -- --

La Bobita 03/26/04 8,229.45 63.45 3.23 60.22 8,169.23 -- --

La Bobita 05/11/04 8,229.45 58.93 3.23 55.70 8,173.75 -- --

La Bobita 05/12/04 8,229.45 58.87 3.23 55.64 8,173.81 -- --

La Bobita 05/13/04 8,229.45 58.77 3.23 55.54 8,173.91 8,181.02 -7.1

La Bobita 06/02/04 8,229.45 59.40 3.23 56.17 8,173.28 8,180.03 -6.7

Well 1 12/17/03 8,187.30 21.88 2.00 19.88 8,167.42 -- --

Well 1 02/19/04 8,187.30 22.93 2.00 20.93 8,166.37 -- --

Well 1 03/26/04 8,187.30 23.45 2.00 21.45 8,165.85 -- --

Well 1 05/12/04 8,187.30 18.44 2.00 16.44 8,170.86 -- --

Well 1 05/13/04 8,187.30 18.34 2.00 16.34 8,170.96 8,181.02 -10.1

Well 1 06/02/04 8,187.30 19.09 2.00 17.09 8,170.21 8,180.03 -9.8

Well 2–1 12/17/03 8,207.92 9.18 2.00 7.18 8,200.74 -- --

Well 2–1 02/20/04 8,207.92 9.09 2.00 7.09 8,200.83 -- --

Well 2–1 03/26/04 8,207.92 8.96 2.00 6.96 8,200.96 -- --

Well 2–1 05/12/04 8,207.92 8.01 2.00 6.01 8,201.91 -- --

Well 2–1 05/13/04 8,207.92 8.02 2.00 6.02 8,201.90 8,201.71 .2

Well 2–1 06/02/04 8,207.92 8.41 2.00 6.41 8,201.51 8,200.78 .7

Well 2–2 12/17/03 8,207.94 10.29 2.00 8.29 8,199.65 -- --

Well 2–2 02/20/04 8,207.94 10.33 2.00 8.33 8,199.61 -- --

Well 2–2 03/26/04 8,207.94 10.20 2.00 8.20 8,199.74 -- --

Well 2–2 05/12/04 8,207.94 8.71 2.00 6.71 8,201.23 -- --

Well 2–2 05/13/04 8,207.94 8.63 2.00 6.63 8,201.31 8,201.71 -.4

Well 2–2 06/02/04 8,207.94 9.23 2.00 7.23 8,200.71 8,200.78 -.1

Well 3 12/17/03 8,255.54 5.61 2.00 3.61 8,251.93 -- --

Well 3 02/20/04 8,255.54 5.62 2.00 3.62 8,251.92 -- --

Well 3 03/26/04 8,255.54 5.30 2.00 3.30 8,252.24 -- --

Well 3 05/11/04 8,255.54 4.10 2.00 2.10 8,253.44 -- --

Well 3 05/13/04 8,255.54 4.13 2.00 2.13 8,253.41 8,252.88 .5

Well 3 06/02/04 8,255.54 4.54 2.00 2.54 8,253.00 8,251.87 1.1
Table 5. Altitude of water levels in La Bobita and Phase III wells and concurrent altitude of stage of Red River, northcentral New Mexico, 2003–04.—Continued

[Permanent measuring point for Phase III wells is top of the 1-inch PVC casing (TOC); NGVD 29, National Geodetic Vertical Datum of 1929; --, no data]

Well 

identification

(fig. 4)

Date

(month/day/

year)

Land-surface 

altitude 

(feet above 

NGVD 29)

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land surface)

Water-level 

altitude 

(feet above 

NGVD 29)

Altitude of 

Red River 

stage 

(feet above 

NGVD 29)

Water-level 

altitude in 

well minus 

altitude of 

Red River 

stage 

(feet)

Well 4–1D 12/18/03 8,398.00 9.10 2.00 7.10 8,390.90 -- --

Well 4–1D 02/19/04 8,398.00 9.70 2.00 7.70 8,390.30 -- --

Well 4–1D 03/26/04 8,398.00 8.70 2.00 6.70 8,391.30 -- --

Well 4–1D 05/11/04 8,398.00 6.38 2.00 4.38 8,393.62 -- --

Well 4–1D 05/13/04 8,398.00 6.58 2.00 4.58 8,393.42 8,392.96 0.5

Well 4–1D 06/02/04 8,398.00 6.69 2.00 4.69 8,393.31 8,391.64 1.7

Well 4–1S 12/18/03 8,398.10 9.09 1.95 7.14 8,390.96 -- --

Well 4–1S 02/19/04 8,398.10 9.79 1.95 7.84 8,390.26 -- --

Well 4–1S 03/26/04 8,398.10 8.68 1.95 6.73 8,391.37 -- --

Well 4–1S 05/11/04 8,398.10 6.49 1.95 4.54 8,393.56 -- --

Well 4–1S 05/13/04 8,398.10 6.61 1.95 4.66 8,393.44 8,392.96 .5

Well 4–1S 06/02/04 8,398.10 6.77 1.95 4.82 8,393.28 8,391.64 1.6

Well 4–2D 12/18/03 8,401.95 12.10 2.05 10.05 8,391.90 -- --

Well 4–2D 02/19/04 8,401.95 13.04 2.05 10.99 8,390.96 -- --

Well 4–2D 03/26/04 8,401.95 11.50 2.05 9.45 8,392.50 -- --

Well 4–2D 05/11/04 8,401.95 7.71 2.05 5.66 8,396.29 -- --

Well 4–2D 05/13/04 8,401.95 8.11 2.05 6.06 8,395.89 8,394.99 .9

Well 4–2D 06/02/04 8,401.95 7.83 2.05 5.78 8,396.17 8,395.27 .9

Well 4–2D 06/03/04 8,401.95 7.83 2.05 5.78 8,396.17 8,394.99 1.2

Well 4–2S 12/18/03 8,402.32 12.47 2.00 10.47 8,391.85 -- --

Well 4–2S 02/19/04 8,402.32 13.41 2.00 11.41 8,390.91 -- --

Well 4–2S 03/26/04 8,402.32 11.89 2.00 9.89 8,392.43 -- --

Well 4–2S 05/11/04 8,402.32 8.40 2.00 6.40 8,395.92 -- --

Well 4–2S 05/13/04 8,402.32 8.70 2.00 6.70 8,395.62 8,394.99 .6

Well 4–2S 06/02/04 8,402.32 8.57 2.00 6.57 8,395.75 8,395.27 .5

Well 4–2S 06/03/04 8,402.32 8.55 2.00 6.55 8,395.77 8,394.99 .8

Water-Level Measurements 51
52 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15

Wells 4–1D, 4–1S, 4–2D, 4–2S, 4–3D and 4–3S were 

installed between about 3,000 and 3,500 ft upstream (east) 

from well 3 (fig. 4). Within each of these three pairs of wells, 

the deeper well (designated with the letter D) was completed 

at depths ranging from 36.67 to 38.49 ft below land surface; 

the shallower well (designated with the letter S) was completed at depths ranging from 18.90 to 19.04 ft below land 

surface. 

Ground-water levels measured in all six wells in May 

and June 2004 ranged from 0.2 to 1.0 ft higher in May 2004 

and 0.8 to 1.8 ft higher in June 2004 than the stage of the Red 

River where lines approximately perpendicular to the bank 

of the river intersect each of the three pairs of wells. These 

water-level measurements indicate that the Red River and the 

underlying ground water are hydraulically connected and that 

ground water has a gradient toward the Red River.

From December 12, 2003 through June 2, 2004, groundwater levels in well 4–1S ranged from 0.07 ft higher to 0.06 ft 

lower than concurrently measured water levels in well 4–1D 

(table 5). During the same period, ground-water levels in 

well 4–2S ranged from 0.05 to 0.42 ft lower than concurrently measured water levels in well 4–2D, and water levels 

in well 4–3S ranged from 0.02 ft higher to 0.81 ft lower than 

concurrently measured water levels in well 4–3D (table 5). At 

the well 4–1 pair, the differences in concurrently measured 

water levels indicate neither a substantial upward nor a substantial downward vertical component of ground-water flow. 

At the well 4–2 pair, the differences in concurrently measured 

water levels indicate that an upward vertical component was 

present and was greater during the spring snowmelt in May 

and June. At the well 4–3 pair, the differences in concurrently measured water levels indicate that neither a substantial 

upward nor a substantial downward vertical component of 

ground-water flow was present except on May 13, 2004, when 

an upward gradient was present and was about 10 times larger 

than during any other of the concurrent measurements. 

Within the reach of the Red River adjacent to the La 

Bobita well and the Phase III wells, the Red River and the 

shallow ground-water system appear to be hydraulically connected from the upstream part of this reach near wells 4–1D 

and 4–1S downstream to near wells 2–1 and 2–2. Between 

wells 2–1 and 2–2 and the La Bobita well and well 1, however, 

the nature of this connection changes, and these systems are 

no longer hydraulically connected or are poorly connected 

near the La Bobita well and well 1. 

Table 5. Altitude of water levels in La Bobita and Phase III wells and concurrent altitude of stage of Red River, northcentral New Mexico, 2003–04.—Continued

[Permanent measuring point for Phase III wells is top of the 1-inch PVC casing (TOC); NGVD 29, National Geodetic Vertical Datum of 1929; --, no data]

Well 

identification

(fig. 4)

Date

(month/day/

year)

Land-surface 

altitude 

(feet above 

NGVD 29)

Depth to 

water 

(feet below 

permanent 

measuring 

point)

Measuring 

point height 

above land 

surface 

(feet)

Depth to 

water 

(feet below 

land surface)

Water-level 

altitude 

(feet above 

NGVD 29)

Altitude of 

Red River 

stage 

(feet above 

NGVD 29)

Water-level 

altitude in 

well minus 

altitude of 

Red River 

stage 

(feet)

Well 4–3D 12/17/03 8,397.86 12.99 1.93 11.06 8,386.80 -- --

Well 4–3D 02/19/04 8,397.86 14.10 1.93 12.17 8,385.69 -- --

Well 4–3D 03/26/04 8,397.86 12.20 1.93 10.27 8,387.59 -- --

Well 4–3D 05/11/04 8,397.86 7.18 1.93 5.25 8,392.61 -- --

Well 4–3D 05/13/04 8,397.86 7.05 1.93 5.12 8,392.74 8,391.77 1.0

Well 4–3D 06/02/04 8,397.86 7.23 1.93 5.30 8,392.56 8,390.80 1.8

Well 4–3D 06/03/04 8,397.86 7.22 1.93 5.29 8,392.57 8,390.80 1.8

Well 4–3S 12/17/03 8,398.00 13.25 2.00 11.25 8,386.75 -- --

Well 4–3S 02/19/04 8,398.00 14.38 2.00 12.38 8,385.62 -- --

Well 4–3S 03/26/04 8,398.00 12.47 2.00 10.47 8,387.53 -- --

Well 4–3S 05/11/04 8,398.00 7.37 2.00 5.37 8,392.63 -- --

Well 4–3S 05/13/04 8,398.00 8.07 2.00 6.07 8,391.93 8,391.77 .2

Well 4–3S 06/02/04 8,398.00 7.44 2.00 5.44 8,392.56 8,390.80 1.8

Well 4–3S 06/03/04 8,398.00 7.45 2.00 5.45 8,392.55 8,390.80 1.8
Summary

In April 2001, the U.S. Geological Survey (USGS) and 

the New Mexico Environment Department began a cooperative study to infer the pre-mining ground-water chemistry at 

the Molycorp molybdenum mine site in the Red River Valley, 

north-central New Mexico. The Molycorp molybdenum mine 

has operated intermittently since the 1920s; ground-waterlevel and water-quality data were not obtained prior to initiation of mining. To infer pre-mining ground-water chemistry, 

wells were drilled in five unmined areas geologically analogous to the mined area—Hottentot Creek, Straight Creek, 

Hansen Creek, near La Bobita campground, and Capulin 

Canyon. 

The purpose of this report is to document and describe 

Phase II and Phase III well installation and development, 

present results of lithologic and geophysical logging, present 

results of hydraulic testing to determine aquifer characteristics, 

and present and discuss water-level measurements collected 

during the period March 2002 to June 2004. This report is one 

in a series of reports that can be used to determine pre-mining 

ground-water conditions at the mine site. 

The main area of study within the Red River drainage 

basin extends west from the town of Red River to the USGS 

streamflow-gaging station near Questa (Questa gage). The 

area upstream from the Questa gage includes approximately 

18 mi of the Red River and 108 mi2 of the Red River drainage 

basin. Weathering of hydrothermally altered bedrock in the 

study area has resulted in steep, highly erosive, and sparsely 

vegetated scar areas that are clearly visible from the ground 

and in aerial photographs. Runoff from intense summer 

rainfall over basins tributary to the Red River can transport 

large quantities of sediment down tributary drainages and form 

debris fans where these tributaries join the Red River. Where 

the tributary drainages contain scar areas, the debris fans are 

large and indicate evidence of active deposition. Large debris 

fans debouching from tributary drainages have caused aggradation of the Red River streambed in river reaches upstream 

from debris fans.

Important water-bearing units in the Red River Valley 

include fractured bedrock, debris-flow deposits, and Red River 

Figure 14. Difference between ground-water altitudes in La Bobita and Phase III wells and altitude of water in Red River, May 13 and 

June 2–3, 2004.

GROUND WATER

LOWER THAN RIVER 

GROUND WATER

HIGHER THAN RIVER 

-12

-10

-8

-6

-4

-2

0

2

4

June 2, 2004, measurement

May 13, 2004, measurement June 3, 2004, measurement

\\Sps1dkslwr\home\pubs\report_figs\12_0029blanchard\working_files\Fig_14

La Bobita well

Well 1

Well 2–1Well 2–2

Well 3

Well 4–1D

Well 4–1SWell 4–2SWell 4–3S

Well 4–2DWell 4–3D

DIFFERENCE BETWEEN GROUND-WATER AND SURFACE-WATER ALITIUDES, IN FEET

Summary 53
alluvium. Debris-flow deposits, debris fans, and Red River 

alluvium are smaller in area but contain most of the ground 

water in the valley. Debris-flow deposits, debris fans, and the 

Red River alluvium typically are less than 1,000 ft wide and 

less than 200 ft thick. 

Twenty-nine observation wells were installed in three 

phases as part of this study in the Red River Valley and tributary drainages. Phase I wells (SC–1A and B, SC–2B, SC–3A 

and B, SC–4A, SC–5A and B) were located in the Straight 

Creek drainage basin along the assumed path of ground-water 

flow in debris-flow deposits from the upstream part of the 

basin to near the mouth of the basin, where Straight Creek 

flows into Red River. Phase II well SC–6A was installed in 

the Straight Creek drainage, wells SC–7A and SC–8A were 

installed in Red River alluvial deposits west of Straight Creek, 

and well SC–9A was installed on the north bank of Red River 

to complete the series of wells in the Straight Creek drainage 

basin. Phase II wells also were installed in the Hottentot, Hansen, and La Bobita drainages and in Capulin Canyon. Phase 

III wells were installed in unconsolidated material along an 

approximately 1-mi reach of the Red River west of Elephant 

Rock campground. 

Eight Phase II observation wells (Hottentot, SC–6A, 

SC–7A, SC–8A, Hansen, La Bobita, CC–1B and CC–2B) 

were drilled using an air-rotary/hammer rig equipped with a 

casing-advance system. The casing-advance system temporarily cased the holes ensuring that the holes did not collapse. 

Each well was constructed using flush-threaded, 4-in. diameter, schedule-80 polyvinyl chloride (PVC) casing and factorycut, 0.010-in. slot size PVC screen. Three Phase II smalldiameter wells were installed using a direct-push rig. Wells 

CC–1A and CC–2A were installed in Capulin Canyon next to 

the air-rotary-drilled wells CC–1B and CC–2B, respectively. 

Well SC–9A was installed at the mouth of the Straight Creek 

and was advanced under the Red River at an angle of 21.5 

degrees from vertical to a total angular depth of 22.5 ft. The 

Phase II small-diameter wells (CC–1A, CC–2A, and SC–9A) 

were constructed of 1-in. diameter schedule 40 PVC with a 

5-ft long screen at the total depth of the hole. 

Ten Phase III small-diameter observation wells were 

installed using a direct-push rig along an approximately 1-mi 

reach of the Red River west of Elephant Rock. Each well was 

constructed of 1-in. diameter schedule 40 PVC casing and a 

5-ft screen at the total depth of the hole. 

Lithologic logs were recorded for all eight Phase II 

drilled wells. Borehole geophysical logging was conducted in 

Phase II wells SC–6A, SC–7A, and SC–8A. Lithologic logs 

were constructed from examination of borehole cuttings. Cuttings were collected at 5-ft intervals from land surface to total 

depth. Natural gamma, induction, and single-detector neutron 

geophysical logging were conducted in wells SC–6A, SC–7A, 

and SC–8A during February 2003 following well completion 

and development. 

In well SC–6A, the geophysical logs indicate that the 

deposits about 11 ft above the water table were dry. The 

lithologic log, however, indicates that the cuttings retrieved 

from this interval were wet. This inconsistency between the 

lithologic log and the geophysical log interpretation indicates that the change in the geophysical log may be related to 

geologic conditions rather than a lack of moisture. For well 

SC–7A, geophysical logs suggest that the deposits above the 

water table were dry to partially saturated. For well SC-8A, 

geophysical logs indicate that deposits were partially saturated at about 70 ft below land surface. Induction and gamma 

logs from 60 to 69 ft correspond to the presence of gravelsized deposits described in the driller’s log. The neutron log 

indicates that porosity decreases with depth over the screened 

interval. 

Aquifer tests conducted during 2003 to estimate the 

hydraulic properties of debris-flow deposits and Red River 

alluvial deposits in and near Straight Creek included a flowmeter survey, slug tests, and a pumping test. A flow-meter survey was conducted in well SC–7A on October 27, 2003, using 

a flow meter that was lowered to about 150 ft and a pump that 

was lowered to about 10 ft below the static water level. The 

well was pumped at a rate of 3.64 gal/min, and drawdown in 

the well reached steady state at 0.07 ft below the static water 

level. Results of the flow-meter survey indicated that about 

77 percent of the water entered the well from a 10-ft-thick 

zone near the top of the screened interval and about 23 percent 

of the water entered the well from a 15-ft-thick zone near the 

bottom of the screened interval. 

Slug tests were performed in wells SC–1A, SC–1B, 

SC–2B, SC–3A, SC–3B, SC–4A, SC–5A, SC–5B, SC–6A, 

SC–7A, and SC–8A during June 3–5, 2003. Water-level 

data were recorded during each slug test using a submersible pressure transducer connected to a data logger. For wells 

with screens in debris-flow deposits (wells SC–1A, SC–3A, 

SC–4A, and SC–6A), the mean and median estimated hydraulic conductivities were 15.25 and 15.35 ft/d, respectively. 

For wells with screens in bedrock (wells SC–1B, SC–2B, 

SC–3B, and SC–5B), the mean and median estimated hydraulic conductivities were 0.12 and 0.08 ft/d, respectively. For 

wells with screens in mixed debris-flow deposits and Red 

River alluvium (wells SC–5A, SC–7A, and SC–8A), the mean 

and median estimated hydraulic conductivities were 73–207 

(estimated range) and 80 ft/d. In general, bedrock has the 

smallest hydraulic conductivity, debris-flow deposits have the 

next highest hydraulic conductivity, and the mixed debris-flow 

deposits and Red River alluvium have the largest hydraulic 

conductivity. 

A pumping test was conducted December 3–4, 2003, 

on well AWWT–1 as the pumped well and wells AWWT–2, 

SC–5A, SC–5B, SC–7A, and SC–8A as observation wells. 

The time-weighted average pumping rate was 106 gal/min. 

Analysis of the pumping test water-level data indicated estimated transmissivity of 12,000 to 34,000 ft2

/d and estimated 

hydraulic conductivity of 230 to 340 ft/d.

Water-level measurements in wells SC–6A, SC–7A, 

SC–8A, and the Hottentot, Hansen, and La Bobita wells show 

that water levels typically rose rapidly during the time of melting of the winter snowpack in the spring and then generally 

54 Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15
declined during the rest of the year. The duration of waterlevel rise, however, appears to be typically about 2 months, 

after which a slow water-level decline occurs during the following 10 months. In the Straight Creek drainage, the waterlevel rise in response to spring snowmelt occurred earlier 

and was smaller at greater distances from the Red River. The 

spring increases in water levels in wells SC7–A and SC–8A 

were about eight times larger than those in well SC–6A. 

Well SC–9A was dry at the time of construction but 

subsequently contained water. Differences between the stage 

in the Red River and water levels in wells SC–8A and SC–9A, 

and the absence of water in well SC–9A at its time of completion, indicate that the Red River had a poor hydraulic connection to the underlying ground-water system and the surfacewater system is perched above the ground-water system at this 

site. 

Water levels in Phase III wells indicate that the Red River 

and the shallow ground-water system appear to be hydraulically connected from near wells 4–1D and 4–1S downstream 

to near wells 2–1 and 2–2. Between wells 2–1 and 2–2 and the 

La Bobita well and well 1, however, the nature of this connection changes, and these systems are no longer hydraulically 

connected or are poorly connected in the vicinity of the La 

Bobita well and well 1. 

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56  Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15
Blanchard and others—Questa Baseline and Pre-Mining Ground-Water Quality Investigation 15−Red River Valley, New Mexico, 2002–04

—

Scientific Investigations Report 2006–5246

Printed on recycled paper

Mine site

Open

pit

Town of

Red River

Study area

Study area

Red River

drainage basin

NEW

MEXICO

Straight Creek scar

Hottentot Creek scar

Red River near

Questa streamflow- gaging station

(08265000)

Questa

ranger station 

La Bobita

campground

0

0

0.5 1.0 1.5 2.0 MILES

0.5 1.0 1.5 2.0 KILOMETERS

Area shown in figure 5 

36° 38’

41’

36° 44’

105° 33’ 30’ 27’ 24’ 105° 21’

Pioneer Creek

Goose Creek

Placer Creek

Malette Creek

Bitter Creek

Bobcat Creek

Moreno Creek

Hematite Creek

Fourth of July Canyon

Black

Canyon

Rio Pecos

Grande

River

MEXICO

TEXAS

Index

map

June Bug scar

June Bug

campground

Area shown in figure 3 

Area shown

in figure 2 

Blind Gulch

Hansen Creek

Little Hansen Creek

Straight Creek

Hottenoto Creek

Area shown in figure 4

Copper

Columbine Creek

Base compiled from U.S. Geological Survey Digital Raster Graphic Data 1:100,000, 1982, and

from U.S. Geological Survey Digital Orthophoto Quadrangle, 1:12,000, 1998

Universal Transverse Mercator projection, Zone 13

Horizontal coordinate information is referenced to the North American

 Datum of 1983 (NAD 83)

Questa