Bureau of Mines

Report of Investigations 5350

I

I

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INVESTIGATION OF SUBBITUMINOUS-COAL BEDS

NEAR HOUSTON, WESTWARD EXTREMITY

OF MATANUSKA COALFIELD, ALASKA

BY R. R. MAY AND R. S. WARFIELD

I

t

United States Department of the Interior-August 1957

- I ---
INVESTIGATION OF SUBBITUMINOUS-COAL BEDS

NEAR HOUSTON, WESTWARD EXTREMITY

OF MATANUSKA COALFIELD, ALASKA

BY R. R. MAY AND R. S. WARFIELD

* * * * * * * * * Report of Investigations 5350

UNITED STATES DEPARTMENT OF THE INTERIOR

Fred A. Seaton, Secretary

BUREAU OF MINES

Marling J. Ankeny, Director

Work on manuscript completed November 1956. The Bureau of Mines will welcome reprinting of this paper, provided

the following footnote acknowledgment is made: "Reprinted from Bureau of Mines Report of Investigations 5350."

August 1957
I

INVESTIGATION OF SUBBITUMINOUS-COAL BEDS NEAR HOUSTON,

WESTWARD EXTREMITY OF MATANUSKA COALFIELD, ALASKA

by

R. R. Mayl/ and R. S. Worfield /

CONTENTS

Page

Summary .................. ....................................... 1

Introduction ..... .... .......... ,...... . ,... ... ........ . 1

Acknowledgments .......... ......... ...... .... .0. ........ 2

Description of area............... ............ ........ .. 2

Location and access .................... ...... 2

Topography. ................... ..... ...... .... ....... 2

Climate (as it affects operations).... ..... .............. 2

History and production,.. .. .... ............ ................... 4

Geology .... . ............................... ...... .......... . 4

The coal ..... .....,,................... ..... .......... 5

Coal sampling and analysis ........................... 5

Mining and preparation...... .... ........ ........... 7

Work by the Bureau of Mines ............ ......................... 7

Preliminary examination... .... ................. ..... 7

Diamond drilling......... ......... ................ ..... 7

Interpretation of drilling results...............,...... 9

Appendix.............. ................................... 4..... 12

Logs of drill holes..... . ................................ 12

1/ Solid fuels mining engineer, Bureau of Mines, Region I, Alaska

district, Anchorage, Alaska.

2/ Mine examination and exploration engineer, Bureau of Mines,

Region I, Juneau, Alaska.

Report of Investigations 5350
ii

ILLUSTRATIONS

Fig. Page

1. Location map, Houston coal-drilling project ................. 3

2. Plan, Houston coal-drilling project......................... 8

3. Section A-A' and graphic logs, Houston coal-drilling project 10

TABLES

1. Section in strip mine near old Evan Jones slope............. 6

2. Section in strip mine 1,200 feet northeast of old Evan

Jones slope ............................................... 6

3. Analyses of face samples from section 1,200 feet northeast

of old Evan Jones slope .................................. 6

4. Analyses of diamond-drill core samples from Houston coaldrilling project ........................ ......... 11
1

SUMMARY

A preliminary examination of the Houston strip-coal mine, situated on the Alaska

Railroad at milepost 175 (61 rail miles north of Anchorage, Alaska) and a review of

all available information resulting from early coal exploration activities in the

area resulted in plans to investigate the coal-bearing formations at depth by means

of diamond core drilling to indicate the existence of additional reserves of coal in

close proximity to railroad transportation, where it would be quickly available to

meet rapidly expanding military and civilian fuel requirements.

From the date of mobilization of equipment, August 28, 1951, until date of suspension, August 18, 1952, 2-,010 feet of diamond drilling was completed. Ten definable coal beds were cut, of which 2 appear to be persistent and minable over an area

of approximately 1/2 square mile. Within this area the 2 minable beds contain

approximately 5,000,000 tons of coal in place. Of the remaining beds, at least two

others may be minable to the eastward near their projected outcrops; however, these

and deeper beds (at least in the vicinity of the drill holes) lie beneath a zone of

pressurized gas and brackish water. From a practical standpoint, continued development and utilization of the coal in this vicinity will depend on the operators' ingenuity in developing cheap mining methods and on diligent prospecting for strippable

coal under the comparatively light glacial cover.

INTRODUCTION

Since the advent and expansion of military installations in south central Alaska,

coupled with the resultant rapid growth of population, the delineation and development

of the Matanuska coal field have assumed considerable importance, particularly in

those parts of the field that are accessible by existing transportation facilities.

Little work of an evaluating nature had been done before this project was undertaken

at the western end of the Matanuska field, which abuts the main line of the Alaska

Railroad at Houston, approximately 60 miles north of Anchorage.

Although the rank of the exposed beds in the immediate vicinity of Houstin is

subbituminous, recent exploration by the Federal Geological Survey indicated a definite tie with the extensive bituminous beds of the Chickaloon coal-bearing formation

now in production a few miles eastward. Discovery of additional minable beds not

only would augment the Houston-area reserve but might lead to the discovery of nearby

reserves which, because of closer proximity to the Talkeetna Mountain uplift, might

have bituminous rank.

From observation of past and present workings and of the indicated geological

attitude of the coal-bearing formation, it appeared that a very limited drilling program would procure the desired information. The following report presents the data

obtained by the drilling program and an interpretation of the data.
2

ACKNOWLEDGMENTS

Many of the historical data, as well as cooperation in appraisal and sampling

before initiation of the project, were furnished by Dr. George Gates and Dr. Farrell

Barnes of the Alaskan Geology Branch, Federal Geological Survey. Core and face samples of coal taken before and during the work were analyzed by the Bureau of Mines

Coal-Analysis Section, Pittsburgh, Pa., under the direction of R. F. Abernethy, chief.

The engineering department of the Alaska Railroad furnished basic alinement and elevation details upon which the survey of the drilling area was based. Tucker & Peterson, lessors, and Duck Flat Co., production contractors, assisted the work by furnishing housing and messing facilities and the occasional use of heavy equipment.

DESCRIPTION OF AREA

Location and Access

The limited area covered by the activities described in this report is within 2

miles of Houston, a station at 240 feet altitude on the main line of the Alaska Railroad at mile 175 (fig. 1). Houston is 61 miles north of Anchorage, near the western

toe of the Talkeetna Range, on the edge of the broad Susitna River Valley. When this

project was in progress there was no highway access, but a road from Pittman (mile

167 on the Alaska Railroad) has since made the mine accessible over the Alaska highway system.

Topography

The Houston-project area is on the eastern edge of the Susitna River Valley,

which is essentially a broad tundra flat cut by many, very small, meandering creeks.

The Alaska Railroad follows the toe of the foothills that slope gently upward toward

the mountains in an undulating series of benches; the project area is beside the railroad and at the base of this terraced slope. The Susitna Valley, which at this point

is fully 25 miles wide, appears to be covered with a semisubmerged, recessional moraine.

Tundra areas on this moraine consist of grassy swamps and pools, with patches of scrubby

spruce and brushy willow. The rising ground to the eastward is covered by glacial deposits of various types and by a thick forest growth; spruce and birch predominate.

As might be expected in an area where bedrock is almost completely concealed, the original coal discovery was made in a cut incidental to railroad construction.

Climate (As It Affects Operations)

The climate here is suitable for outside operations during only about 6 months of

the year, unless shop facilities are heated and insulated and unless all-weather roads

are constructed and at considerable expense. January and February are the coldest

months, with an average daily low of minus 20°. During June, July, and August the

daily high usually is in the 60's, but during calm, clear days the temperature often

is in the 80's. Annual precipitation records for the immediate vicinity of Houston

are not available, but estimates indicate a combined rain and snow content of about

50 inches. Except where it is drifted, winter snows seldom accumulate to depths of

more than 3 feet. Summer rains generally are unpredicatable as to monthly intensity;

they seldom are heavy but often are persistent enough during early and late summer

to hamper hauling and road-maintenance work with heavy equipment.

The outdoor working season for stripping overburden usually is mid-May to midOctober, although much subsidiary work can be done a month or so before and after

these dates; however, unless expensive methods are adopted, mining operators seldom
3

Figure 1. - Location map, Houston coal-drilling project.
4

strip overburden until June, because the ground usually freezes to a depth of 5 to 7

feet; thawing produces a tremendous amount of surface water, which bogs down most

heavy equipment.

HISTORY AND PRODUCTION

Coal was discovered in a right-of-way cut on the Alaska Railroad at Houston

station in 1917. Although the early history of the development is somewhat clouded,

it is known that, between 1917 to 1920, a coal-prospecting permit was granted on the

10-acre tract at the discovery site and that 2 slopes were driven on the coal measures. According to reports, the slopes entered 2 beds of coal, which were 3-1/2 and

5 feet thick, respectively; the beds dipped 6° to 15° northeasterly. Production during this period is estimated at 10,000 to 15,000 tons of coal, which was sold to the

Alaska Railroad and to the domestic market in Anchorage. All of the original workings have long been caved; even the caves are completely obscured by brush and slides.

The site of this early activity is approximately one-half mile southeasterly of the

present workings, from which it is separated by a low-lying muskeg swamp; therefore

correlation of the discovery beds with beds in the project area would require considerable prospecting work beyond the scope of this project.

Between 1920 and 1934 no mining or development work of consequence was done near

Houston. In 1934 Arthur Heaven was granted a 160-acre homestead, which included

patent rights to underlying coal. In 1935 Evan Jones obtained prospecting permits

for 874.82 acres adjoining the homestead in sections 17, 18, and 20; in the same year

he started a slope mine near the present position of the southeast corner of the

strip pit. About 12,000 tons of coal was produced from the slope and from a few

rooms before the operation was suspended in 1940. Between 1938 and 1940 Jones joined

in partnership with George Tucker and Ralph Peterson; during this period the Heaven

patent was purchased and became the nucleus of later operations. This partnership

was terminated in 1940; thereafter permits were allowed to lapse until a revival of

interest in 1948, when an expanding military market became apparent.

In 1948 Tucker and Peterson organized the Houston Coal Co. and acquired a permit

for access to an additional 1,800 acres next to the Heaven patent; from 1949 through

the 1952 season approximately 65,000 tons of coal was marketed. Most of the coal was

passed through a crushing, screening, and washing plant, which contained a Forrestertype jig capable of handling 15 to 25 tons per hour. Production during 1951 and 1952

was under a management-sales agreement with the Duck Flat Co., a Los Angeles organization. Virtually all production went to the military installations at Anchorage.

GEOLOGY

The geology of the Matanuska coal field is best known from the writings of Go C.

Martin of the Federal Geological Survey, who first made a general reconnaissance of

the region in 1905 and subsequently made detailed studies of the lower3/ and upper4/

parts of the field in 1910 and 1913, respectively. As defined in early descriptions,

the upper or eastern part of the Matanuska field included the Anthracite Ridge and

Chickaloon districts; the lower or western part included the Eska and Moose Creek

areas, as well as Wishbone Hill. Recent reconnaissance by the Geological Survey

along the lower reaches of the Little Susitna River and its tributaries and the work

at Houston by the Bureau of Mines indicate that the Matanuska field extends westward

3/ Martin, G. C., and Katz, F. J., Geology and Coalfields of the Lower Matanuska

Valley, Alaska: Geol. Survey Bull. 500, 1912, 98 pp.

4/ Martin, G. C., and Mertie, J. B., Jr., Mineral Resources of the Upper Matanuska

and Nelchina Valleys: Geol. Survey Bull. 592, 1914, pp. 273-299.
I

5

from Moose Creek and includes the northern edge of the lowlands lying north of Knik

Arm. Barnes designates these lowlands as the Little Susitna district of the Matanuska

coalfield; Houston and the project area are in this district.5/

The following generalized description of the geology of the Matanuska coalfield

is summarized from the above-cited publications, to which the reader is referred for

details:

All coal measures in the field occur in the Chickaloon formation (Tertiary),

which is composed of 3,000 to 5,000 feet of claystone, siltstone, sandstone, thin

beds of fine-grained conglomerate, and many beds of coal. The Chickaloon formation

is overlain by the Eska conglomerate (Tertiary) and underlain by the Matanuska and

Arkose ridge formations (Upper Cretaceous). The Eska conglomerate is not present in

the stratigraphic section at Houston. Neither the Matanuska formation nor the Arkose

ridge formation is exposed near Houston.

At Houston and throughout the field individual beds in the Chickaloon formation,

including the coal, tend to thin out or intergrade within relatively short distances.

These changes in bed thickness are believed to be due primarily to the original lenticular structure of the sedimentary deposits but also may be due in part to the

crumpling and pinching out of the soft shales incident to folding of parts of the

region; correlation of individual beds (including coal) for more than short distances

is therefore uncertain or impossible.

Correlation of the coal measures between districts, and often between mines in

the same district, is complicated further by differences in the character of the coal

that result from differences in the amount of faulting and folding from place to place.

The coal at Houston is subbituminous; it occurs in relatively flat lying beds that

have suffered little or no deformation.

THE COAL

Coal Sampling and Analysis

The following sections and samples were taken by R. R. May, Bureau of Mines mining engineer, and F. F. Barnes, geologist, Geological Survey, September 26, 1950.

Sections and samples were taken in accordance with Bureau of Mines standard procedure

and forwarded to Pittsburgh for analysis.

5/ Barnes, Farrell F., and Payne, Thomas G., The Wishbone Hill District, Matanuska

Coal Field, Alaska: Geol. Survey Bull. 1016, 1956, p. 2.
Roof: Gray shale, coaly at base.

Coal, dull glossy/ .......................................

Bone, bright-coal streaks.................................

Coal, bright!/.............................................

Coaly shale./.............................................

Coaly shale and bone.2/...................................

Coaly/ ........................

Coaly shale2./... .............................................

Coal, clay slips./. .. . .. . .. .. . . ... ... ... .... ... .. ... .. ... .

Bone......................................................

Floor: Coaly shale...............................................

6

TABLE 1. - Section in strip mine, near old Evan Jones slope

(top bench of strip-mine bed)

Roof: Gray claystone, silty. Feet Inches

Coaly shale to bone...................................... 0 2-1/2

Coal . ................................. .................. .. 1-1/2

Coaly shale................ ................................ 1

Coal ..................................... 10

Bone ................................................... ... 7

Coal, bright ........................ ........ ............. 1 1-1/2

Bony coal..... . ..................................... ...... 3-1/2

Coaly shale.l/ ............................................. 2

Claystone, thin coal stringers............/ ............ .............. 8

Claystonel/ ................................................. 2 0

Bony coal (top of lower bench) ............................. Partly exposed.

1/ Denotes parting between upper and lower benches.

TABLE 2. - Section in strip mine 1,200 feet northeast of old Evan Jones slope

(full section, both benches)

I

Feet Inches

0 9

7

1 0-1/2

1 4

2 4

1 0

4

6

2

Partly exposed.

1/ Included in analysis,lab. No. D-51894 (table 3).

2/ Denotes parting between benches.

3/ Included in analysis,lab. NO. D-51895 (table 3).

TABLE 3. - Analyses of face samples from section 1,200 feet northeast

of old Evan Jones slope

Air-drying Vol. Fixed

Sample loss Condition Moisture matter Carbon Ash Sulfur B.t.u.

D-51894 7.6 A 20.3 31.6 38.9 9.2 0.4 9,210

B 13.7 34.2 42.1 10.0 .5 9,970

C 39.6 48.9 11.5 .5 11,550

D 44.8 55.2 .6 13,060

D-51895 6.7 A 17.4 32.5 36.6 13.5 .4 9,160

B 11.5 34.8 39.3 14.4 .5 9,820

C 39.3 44.4 16.3 .5 11,090

D 47.0 53.0 .6 13,250

Condition: A - as received.

B - air-dried.

C - moisture-free.

D - moisture- and ash-free.

Analyses by H. M. Cooper, Bureau of Mines, Pittsburgh, Pa.
7

Mining and Preparation

Coal at the Houston mine (see table 1 for average section) is stripped and then

mined in successive benches by drilling vertical blast holes with a portable electric

auger on 5-foot centers; these holes are blasted lightly with 20-percent gelatin.

After being broken, the coal is loaded by power shovel onto trucks, which haul it to

the washing plant approximately 1 mile from the pit. The raw coal tends to be coarse

and slabby, with many iron-silica-sulfur concretions; therefore it requires preliminary breaking before being fed to the rolls. This breaking is accomplished by using

a small crawler tractor to crush oversize through an 8-inch grizzly into the rollcrusher feed bin. Crushed coal for jig feed is sized to suit current contract specifications, which usually require 2-1/2 inches top size. This product is fed either

directly to through surge bins to a steam-driven Forrester-type coal jig with a 4-

by 4-foot plunger section and a 4- by 6-foot bed section. The washed-coal discharge

passes over a double-deck shaker sizing screen, with impinging sprays. Screen sizing

varies with contract purchase specifications; fines may be optionally recovered in an

Esperanza-type classifier in closed circuit with washer and screen or discarded separately. Because the plant level at the screen discharge is 30 feet or more above the

car-loading siding, gondolas are loaded by chuting the coal to the cars. For best

washing results plant capacity is 15 to 20 tons per hour, but careful mining often

permits considerable overloading without appreciable detriment to the quality of

finished coal.

Observation of the plant operation under varying conditions indicates that the

Forrester jig is not an ideal medium for separating this coal and its inherent impurities. Although the tendency of this coal to break in thin slabs undoubtedly affects jigging separation, it is apparent that there is a rather narrow differential

in specific gravity between the shale-bone-coal components in this particular bed

system.

WORK BY THE BUREAU OF MINES

Preliminary Examination

In September 1950, accompanied by F. F. Barnes of the Geological Survey, the

writer inspected the mining activity at Houston. Bed sections were recorded, and

samples were taken from the strip pit (see tables 1, 2, and 3). After the prevalent

strike and dip of the measures (which were partly exposed for nearly a mile along

the railroad) were ascertained, it was tentatively concluded that numerous beds on

very moderate dips probably were present in the area.

Before this examination the current lessors had put down several shallow auger

holes in a mile-long area that extended a half mile or so from the railroad; these

holes penetrated the overburden into bedrock until coaly material was found. Because this coaly material was encountered within narrow ranges in a high percentage

of the holes, it was assumed that the coal bed was undulating in some conformance

with the existing topography and that the bed would be strippable throughout a large

area. However, later evidence disproved this assumption; consequently, it was decided

that a core-drilling pattern that would consist of 2 or 3 holes at intervals downdip

would be required to clarify the situation.

Diamond Drilling

A Bureau of Mines diamond drill was shipped to Houston in late August 1951. The

first hole was started near the strip pit highwall. This location (see fig. 2) was
-9

/\

\.4

Legend

Doimond drill hole

8

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*^

oMP4qge Ipoo SOC

Figure 2. - Plan, Houston coal-drilling project.
chosen to establish initial correlation of the coal measures with reference to the

existing mine workings. Drilling conditions were difficult from the start; consequently, progress was slow. A heavy flow of gas and brackish water, which was encountered during freezing weather, caused a shutdown November 10 at a hole depth of

481 feet 7 inches. The condition of the hole precluded resumption of drilling at

this location at the beginning of the next season.

Hole 2 was started May 29, 1952, at a new location; it reached a depth of 1,142

feet, which was considered sufficient to intercept any coal beds likely to outcrop

or to come within practical mining depth within a radium of a mile or so. Hole 2

was completed August 5, 1952, and the drill was moved to the third location farther

downdip, where drilling was resumed August 10.

Hole 3 was completed August 18 at a depth of 386 feet. Termination at this

relatively shallow depth was decided upon as soon as it appeared that a positive

point of correlation with beds in hole 2 had been reached.

Holes 2 and 3 were spaced at intervals of 2,050 and 2,910 feet, respectively,

which was considered the maximum distance allowable for accurate correlation. Depths

were governed by practical considerations of possible future mining operations within

the immediate Houston area.

The locations of the drill holes, pit, and washing plant and the topography of

the Houston area are shown in figure 2. Graphic logs and a section through the drill

holes are shown in figure 3. Analyses of core-drill samples are presented in table 4.

Detailed descriptive logs of the drill holes and the results of megascopic examination of coal core sections are given in the appendix.

Interpretation of Drilling Results

The area of conclusive results, particularly with regard to estimation of reserves, should be limited to no more than a rectangular area, approximately 1 mile

by 1/2 mile, whose long axis is roughly along the line of the 3 holes drilled. A

number of thin coal beds dip 5° to 10° northwesterly; these beds may overlie or

underlie the strip bed. Within this area no appreciable faulting or folding is

apparent, but some minor folds or displacements may be concealed by the cover of

glacial deposits and forest growth.

Although several beds appear to be minable and an appreciable tonnage is indicated, it would be inadvisable to accept the reserve estimates without careful

consideration of local peculiarities. Some of the factors that might modify the

reserve estimates follow:

(1) Washer recovery varies widely according to the type of cleaning equipment

and mining practice.

(2) It has been many years since underground mining has been practiced at this

location; consequently, no accurate recovery factor is assignable.

(3) Because of adverse drilling conditions, friability of the cored material,

and the haphazard distribution of concretions in the coal measures, considerable

difficulty was experienced in recovering core samples for other than visual inspection and for comparison with coal currently being mined; therefore, core-drill samples may not be exactly representative of the thickness and character of the coal

beds drilled.

9
300

200

100

0

- 100

-200

-300

-400

-500

-600

-700

-800

10

Collar El. 249 Collar El. 330 Collar EL 303

l. ,t, ll . :::hl'i111,' l :ii: , 'li:J',i : : ::llal*. l:l::h i :,'lt:'o;' :':' I 'r :I.ij : :1 ::l1 I : N I iji 't: ' |: ;' :i : . :O :: :;:: :: -' 

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Figure 3. - Section A-A' and graphic logs, Houston coal-drilling project.

I
TABLE 4. - Analyses of diamond-drill core samples from Houston coal-drilling project

proximate analysis, Ultimate analysis, Fusability of ash,

percent - percent O F.___

0C .4 C i O I i 4 o g .0 i C 0 bOZ4J I

1 10.8 329 37.3 .0 5.3 53 1.4 20.8 0.4 19.0 929 2,310 0 2, 740 .5 D-74890 2 32.1 -3. 3& . 2 .3 CP 9,00 r-C 15 1.3 4 

(Hole 4) 3 36.9 21.3 4.6 59.5 1.5 41.8 12.7 .4 21.3 10,420

J-J *-4 - 0t 0 0 0 3 r M 4a ai ) 4 i- N

Lab. 0 c4 r 14- - 51 4 75.6 2.0 4- 4 16. -4 .8 ri .5 g H-4 1,240 O4 ct CL O B > Xi a0 53 c aM

No.1! c z > E r0 U c z Zc M 'l4.J 4 4

1 10.8 32.9 37.3 19.0 5.3 53.1 1.4 20.8 0.4 19.0 9,290 2,310 2,620 2,740 1.53

D-74890 2 13.0 32.1 36.4 18.5 5.4 51.8 1.3 22.7 .3 18.5 9,070

(Hole 1) 3 36.9 41.8 21.3 4.6 59.5 1.5 12.7 .4 21.3 10,420

4 46.9 53.1 5.8 75.6 2.0 16.1 .5 13,240

1 9.5 30.9 33.2 26.4 4.9 48.0 1.2 19.2 .3 26.4 8,400 2,330 2,620 2,840 1.61

D-74891 2 12.1 30.0 32.2 25.7 5.0 46.7 1.2 21.1 .3 25.7 8,160

(Hole 1) 3 34.1 36.7 29.2 4.2 53.1 1.4 11.8 .3 29.2 9,280

4 48.2 51.8 5.9 75.0 1.9 16.8 .4 13,100

1

D-99651 2 10.2 30.9 38.1 20.8 .2 9,140 2,570 2,690 2,890

(Hole 2) 3 34.5 42.3 23.2 .3 10,180

4 44.8 55.2 ___.3 13,250

1/

2/

3/

Pittsburgh laboratory number; see table FoLlowing ana logs tor description

1, Air-dried; 2, as received; 3, moisture-free; 4, moisture- and ash-free.

Determined by modified method.

ot samples.

Description of drill-core samples, Houston project:

Lab. No. D-74890: Hole 1; core logged 27 feet 3 inches to 30 feet 3 inches; core received 32 inches;.

3-3/4 inches bone rejected; 4 inches coal loss in drilling; 28-1/4 inches coal in this sample.

Lab. No. D-74891: Hole 1; core logged 33 feet 1 inch to 35 feet 8 inches; core received 30 inches;

6-1/2 inches bone rejected, 1 inch bone loss in drilling; 23-1/2 inches coal in this sample.

Lab. No. D-99651: Hole 2; core logged 437 feet 6-1/2 inches to 441 feet 0 inch; core received 41-1/2

inches; 8-1/2 inches bone rejected; 33 inches coal in this sample.
Ft.

Del

From0

.,

11

22

23

27

27

30

30

30

31

31

32

32

33

0

12

As a basis for calculating tons of coal in place, the common factor for Alaskan

subbituminous coals is 1 ton of mined raw coal (plant feed) per cubic yard in place

in the mine. Two beds known to average 42 inches and more are the "pit" bed and a

bed lying approximately 250 feet (stratigraphically) below. Other beds are simply

grouped in the category "14 inches and more"; 2 of these may be 42 or more inches

thick; however, the minability of the beds should not be inferred without more

thorough investigation. On the above basis, the total amount of coal in the drilled

area is estimated to be as follows:

Tons in place

Pit bed, average 5 ft. of coal .................... 2,580,000

250 bed, average 4 ft. of coal.................... 2,000,000

Otheri/, average total, 19 ft., 6 in. .............. 10000000

Total .... .................................. 14,580,000

1/ Appearance and specific gravity comparable to pit product.

Study of the drilling logs, projection of the limited geologic evidence, and

consolidation of known historical evidence in this locality indicates that investigation to the southeast for 1/2 to 1 mile might expose strippable beds amenable to

more economical mining. As noted in the logs and elsewhere in this report, a considerable quantity of gas was encountered at a well-defined horizon in holes 1 and

2. Study of this phenomenon was beyond the scope of this investigation. The gas

was predominantly methane.

APPENDIX

Log, Drill Hole 1

Location: 832.5 feet S. and 1,080 feet W. of NE. corner, sec.

Seward Meridian, Houston, Alaska.

20, T. 18 N., R. 3 W.,

Elevation: Collar of hole - 303 feet.

In.

0

9

1

3

4%

3

9

6

9

2%

4

1

Ft.

)th

To11

22

23

27

27

30

30

30

31

31

32

32

33

35

In.

0

9

1

3

4%

3

9

6

9

2%

4

1

12

Clay overburden.

; Material

Interbedded fine sandstone and

silty claystone.

Ironstone.

Interlaminated fine sandstone

and silty claystone.

Bone.

COAL, dull; thin anthraxylon

bands and lenses.

Bone.

Ft.

11

Thickness

11

4

2

1

0

In.

9

4

2

1%

84

2'

6

9

3

51

1%

9

11%

t

Remarks

Thin glacial cover

previously stripped.

Roof, "Pit" bed.

Core loss, 4 in.

Core loss, 7 in.

Shale, dark gray, coaly streaks

Claystone, dark gray, coaly I

Shale, dark gray, carbonaceous.

COAL, dull, thin anthraxylon

lenses.

Shale, dark gray, carbonaceous.

Claystone, coaly.

COAL, dull; thin anthraxylon

streaks and lenses.
Ft.

35

35

35

38

39

43

46

47

49

52

52

53

53

75

From77

80

81

82

86

86

87

90

92

99

109

242

243

258

296

300

302

312

322

323

332

Depth

Y2

3

8

0

4

7

8

0

2

2

5

3

8

2

In.

13

Hole 1 (Con.)

35

35

38

39

43

46

47

49

52

52

53

53

75

77

Ft.

To80

81

82

86

86

87

90

92

99

109

242

243

258

296

300

302

312

322

323

332

333

In.

3

8

0

4

7

8

0

2

2

5

3

8

2

2

10

8

1

2

5

9

5

1

6

6

0

9

9

9

5

6

8

11

7

2

10

Bone, broken.

Bone.

Claystone, fel

Claystone, co.

Clays tone.

Claystone, si

Ironstone.

Claystone.

Claystone, si

Ironstone, coI

Claystone, si

Bone.

Claystone, si.

Sandstone, me,

upper and lot

Claystone, si:

Sandstone, sit

Claystone, si'

Sandstone, si:

Claystone, si:

Sandstone, si:

Claystone.

Claystone, si:

Ity.

dium, grading

wer strata.

lty.

lty.

Ity.

lty.

lty.

Ity.

Material . , .,,,, .]

w coaly streaks.

aly.

lty streaks.

lty streaks.

ncretionary.

lty.

into

Ity; sandy streak.

0

Ft.

and coal fragments.

Claystone, silty; occasional

coaly fragments

Sandstone, clayey matrix.

Sandstone, soft, medium to

fine, containing multiple beds

2

1

4

3

2

3

21

2

3

4

1

2

1

7

10

132

1

15

38

3

2

10

10

8

1

Thicknes

In.

5

4

4

3

1

4

2

0

3

10

5

6

0

4

of hard pebbles (quartz, chert

rhyolite, felsite, basalt) and

occasional coal fragments.

Claystone, bone streaks.

Claystone, silty

Interbedded fine sandstone,

siltstone, and claystone;

occasional coaly streaks.

Claystone, coaly; many brightcoal bands.

Claystone, coaly; few brightcoal bands up to 1 in. thick.

Interbedded claystone and siltstone; occasional coaly

fragments.

Siltstone, sandy streaks.

Claystone, coaly.

Interbedded siltstone and

fine sandstone.

Interbedded siltstone and

claystone.

Remarks

Core loss, 1 in.

Floor, "Pit" bed.

Bedding almost horizontal; infrequent

crossbedding.

Core loss, 2 ft. 5 in.

Core loss, 111 ft.

Core loss, 2 ft.

Core loss, 1 ft.

Core loss, 2 in.

U
Ft.

333

334

334

335

336

341

341

342

345

351

353

353

372

376

387

387

388

393

394

402

403

435

453

456

471

De

FromIn.

-L

10

5

9

2

14

Hole 1 (Con.)

Ft.

334

334

335

336

341

341

342

345

351

353

353

372

376

387

387

388

393

394

402

403

435

453

456

471

481

)tnToIn.

5

9

2

0

Material

Siltstone.

Shale, soft, dark.

Claystone.

Shale, soft, dark, occasional

coal fragments.

Interbedded siltstone and fine

sandstone.

Sandstone, soft.

Interbedded siltstone and fine

sandstone.

Sandstone, soft.

Interbedded siltstone and

claystone.

Claystone, soft, dark.

Siltstone.

Interbedded claystone, siltstone, and fine sandstone.

Sandstone, soft.

Interbedded claystone and

shale, silty streaks.

COAL, hard, bright; conchoidal

fracture.

Claystone, coaly.

Claystone, silty streaks.

COAL, hard, bright, bony

streaks.

Interbedded claystone and

siltstone.

Sandstone, medium fine.

Sandstone, medium fine; soft

layers and occasional coaly

Ft.

Thickness

.-- .... ... .

0

5

2

6

1

18

4

10

1

5

7

1

32

17

3

14

10

7

4

5

10

2

7

6

11

3

7

6

6

9

9

1

1

0

8

9

3

6

6

0

9

6

In. Remarks

Core loss, 6 in.

4

10

10

4

4

1

4

4

1

7

streaks.

Sandstone,

bands.

Sandstone,

Sandstone,

cemented.

soft, few pebble

soft, medium fine.

porous, poorly

Core loss, 16 ft. 2 in.

Core loss, 8 ft. 9 in.

Gas flow accompanied by

brackish water, static

pressure in excess of

15 lb. per sq. in.

Bedding remains almost

horizontal; little distortion evident.

l

Sandstone, alternating soft

and dense, pebble bands, bottom of hole in hard, fine

sandstone. - ^ - - . --
Ft.

0

19

21

21

From33

80

105

106

115

116

126

129

173

175

176

181

182

183

184

186

186

204

205

241

244

260

310

313

Deoth

15

Log, Drill Hole 2

Location: 710 feet S. and 2,150 feet E. of NW. corner, sec. 20, T. 18 N., R. 3 W.,

Seward Meridian, Houston, Alaska.

Elevation: Collar of hole - 330 feet.

0

0

6

11

In.

19

21

Ft.

21

33

80

105

106

115

116

126

129

173

V

4

175

176

181

182

183

184

186

186

204

205

241

244

260

310

313

320

TnIn.

0

6

11

6

0

2

0

9

3

2

0

3

1

7

9

3

7

9

4

11

5

2

2

2

9

3

4

9

Material

Overburden, soil and gravel.

Sandstone, medium coarse; iron

stains.

Shale, carbonaceous.

Interbedded silty claystone

and siltstone.

Sandstone, soft, occasional

pebble bands and coaly

streaks.

Claystone, occasional ironstone nodules, coal fragments.

Siltstone, dense

Claystone.

Siltstone, dense.

Claystone.

Claystone, coaly, frequent

coal bands.

Interbedded claystone, siltstone, and very fine sandstone; occasional pebbles and

coaly streaks.

Interbedded bony coal and coaly

claystone.

COAL, dull; bony streaks.

Claystone; coal streaks and

fragments.

Claystone, coaly.

COAL, dull; bony streaks.

Shale, dark, coal streaks.

Claystone.

Claystone, coal streaks.

Claystone, siltstone bands,

and very fine sandstone bands.

Shale, dark; coal streaks.

Interbedded claystone, siltstone and very fine sandstone.

Sandstone, soft.

Claystone, silty; few sandy

streaks.

Sandstone, soft, occasional

pebble bands.

Conglomerate, pebble; soft

sandstone matrix.

Sandstone, soft to dense.

Thickness

Ft.

19

2

11

46

25

9

9

2

44

1

1

5

1

1

1

17

36

3

16

49

3

7

In.

5

7

6

2

10

9

6

11

10

3

10

6

2

6

4

2

7

7

6

9

0

0

7

6

1

5

0

6

Bedding, where seen,

almost horizontal.

Core broken, pseudocoal bed.

Roof, "Pit" bed.

Floor, "Pit" bed.

Core loss, 2 ft. 3 in.

Remarks

3

4
Ft.

Ue

From320

340

342

372

- . 1.

376

383

399

412

432

435

435

435

436

437

437

438

438

440

440

441

441

445

461

461

461

462

462

463

477

484

508

509

511

16

Hole 2 (Con.)

7

9

In.

10

6

11

7

0

4

2%

4

9

10%

1X

6%

/2

3

2

8

0

3

7

3

9

11

1

11

8

0

0

1

10

5

342

372

376

383

399

412

432

435

435

435

436

437

437

438

438

440

440

441

441

445

461

461

461

462

462

463

477

484

508

509

511

511

To- ToFt.

340

11

7

10

7

0

4

2%

4

9

10l

1%

6%

3

2

8

0

3

7

3

9

11

1

11

8

0

0

1

10

5

8

6

In.

Sandstone, dense; rew peDbbes

and cobbles.

Conglomerate, pebble, in soft

sandstone matrix.

Claystone, silty bands,

occasional ironstone concretions and coaly streaks.

Sandstone, soft, fine to

medium.

Claystone to silty claystone,

occasional ironstone concretions.

Claystone, carbonaceous; coal

fragments.

Sandstone, soft; few pebbles | 19

and occasional claystone bands

and coaly fragments.

Sandstone, soft. 2

Conglomerate, pebble and 29

cobble, soft sandstone matrix.

Material Ft.

COAL.

Siltstone.

Bone.

COAL.

Bone.

COAL.

Bone.

Bone, coal streaks.

Bone.

COAL.

Bone.

Claystone, coal streaks.

Interbedded claystone, siltstone, and very fine sandstone.

Sandstone.

Claystone.

Sandstone, soft.

Claystone.

Claystone, coaly.

Claystone, occasional sandy

streaks.

Sandstone, crossbedded, fine

medium, few clay streaks.

Claystone to silty claystone.

Sandstone, soft.

Claystone.

Claystone, coaly.

4

6

15

13

19

3

9

In.

Thickness

1

1

4

15

13

7

24

1

1

5

8

3

9

5

4

5

1%

21⁄4<

5

6

2%

11

6

4

3

4

8

6

2

2

10

9

4

0

1

9

7

3

Remarks

Bedding where seen

nearly horizontal.

Core loss, 2 ft.

Roof of bed corresponding to log, hole

1, 296 ft. 9 in. to

302 ft. 6 in.

Floor.

Bedding nearly flat.

to
Ft.

FromI

Depth

*

511

533

533

543

545

571

605

610

648

652

666

675

692

697

726

728

729

730

733

735

740

742

744

753

805

832

|In.

17

Hole 2 (Con.)

0

8

0

3

11

0

4

4

10

3

0

0

0

3

2

7

11

7

7

7

8

6

3

11

8

To533

533

543

545

571

605

610

648

652

666

675

692

697

726

728

729

730

733

735

740

742

744

753

805

832

837

Ft.

0

8

0

In.

3

11

0

4

4

10

3

0

0

0

3

2

7

11

7

7

7

8

6

3

11

Material

Claystone and fine sandstone,

interbedded and crossbedded.

COAL, bony.

Interbedded claystone and fine

sandstone.

_ _ _ _ -

Sandstone.

Conglomerate, pebble to

soft sandstone matrix.

Sandstone, soft.

Conglomerate, pebble to

soft sandstone matrix.

Thickness

banasUone, claystone incluslons

Sandstone, dense; calcitefilled fractures.

Conglomerate, soft matrix.

Dense sandstone, coaly

fragments.

Conglomerate, soft matrix.

Claystone, silty.

Claystone, silty; few bands of

fine sandstone and occasional

ironstone concretions and

coaly streaks.

Claystone, coaly.

Claystone.

Claystone, coaly.

Interbedded claystone and fine

sandstone.

Claystone, coal streaks.

Claystone, sandy streaks, and

lenses.

26

cobble, 33

5

cobble, 38

21

9

. 2

Ft.

4

13

8

17

5

29

1

1

1

2

2

5

In.

8

4

3

8

1

4

0

6

5

9

0

0

3

11

5

4

8

0

0

1

10

9

8

10

3

4

Remarks

Transition.

Bedding 15°, brackish

water with evident

gas pressure.

Core loss, 28 ft. 8 in.

Core loss, 2 ft. 1 in.

Core loss, 30 ft. 9 in.

Slickensides.

Core loss, 12 ft. 11 in.

Core loss, 7 ft. 1 in.

Core loss, 12 ft. 9 in.

Core loss, 7 in. Gas and

water increasing down

to this stratum. Static

pressure up to 45 lb.

Another gas channel

apparent at 775 ft.;

not measurable.

I

f Sandstone, fine to medium cross- 2

bedded; coaly streaks and

occasional included pebbles.

Claystone, coaly. 1

Interbedded claystone and fine 8

sandstone.

Sandstone, fine to medium and 52

dense to porous, occasional

claystone blebs, and pebble

band at 794 ft.

Claystone, silty and sandy 26

streaks.

Sandstone, soft; claystone and 4

coaly streaks.

9

9 0
Ft.

837

840

843

847

848

850

876

876

880

895

897

Frnm903

906

913

917

937

943

979

985

985

986

987

987

988

988

1,013

1,044

Depth

U

9

3

18

Hole 2 (Con.)

10

3

8

0

6

8

8

10

IIn.

840

843

847

848

850

876

876

880

895

897

903

Ft.

906

913

917

937

943

979

985

985

986

987

987

988

988

1,013

1,044

1,072

3

8

0

6

8

8

In.

9

3

10

8

To10

Material

Claystone, sandy and coaly

streaks.

Claystone, coaly; many bright

coal bands.

Sandstone, soft; occasional

claystone streaks.

Claystone.

Claystone, dark; bright coal

streaks.

Interbedded claystone and siltstone.

Sandstone, crossbedded;

streaks of iron carbonate.

Claystone, dark; occasional

coal streaks.

Interbedded claystone and

silty claystone.

Sandstone, fine, dense.

Interbedded claystone and

siltstone.

Claystone, coaly.

Interbedded claystone, siltstone, and fine sandstone.

Claystone, coaly; bright

streaks.

Interbedded claystone and siltstone; occasional ironstone

concretions.

Claystone, coaly; many bright

coal bands and streaks.

Interbedded claystone, siltstone, and fine sandstone;

occasional ironstone concretions.

Sandstone.

COAL, bony and bright.

Claystone, coaly.

COAL, bright.

COAL, bony and bright.

COAL.

Claystone, coaly.

Interbedded claystone and siltstone; 3-ft. zone of ironstone

concretions at 994 ft.

Sandstone, fine to medium;

occasional claystone streaks.

Sandstone; frequent conglomerate lenses of indeterminate

thickness.

3

Chickness

2

4

2

25

4

15

2

5

2

7

4

19

6

35

6

1

25

30

27

Ft. In.

6

7

5

5

4

6

2

0

2

10

5

5

2

11

0

5

0

9

5

0

3

8

5

2

10

6

9

Remarks

I

Tv

Bedding of all above

strata varies from 0°

to 15°. i

Core mangled; no loss.
C

43

48

5C

51

53

53

53

55

58

60

87

87

90

96

97

I

0

6

6

5

11

2

5

7

0

7

4

6

9

10

11

6

48

50

51

53

53

53

55

58

60

87

87

90

96

97

103

103

122

123

125

126

126

126

19

Hole 2 (Con.)

I

t

De th . .

From- To- Thickness

Ft. In. Ft. In. Material Ft. In. Remarks

1,072 0 1,097 1 Interbedded claystone and 25 1

silty claystone.

1,097 1 1,105 10 Claystone, dark; frequent 8 9

bright-coal streaks and

scattered sandstone concretions.

1,105 10 1,106 2 Claystone. 4

1,106 2 1,112 3 Interbedded claystone, silt- 6 1

stone, and fine sandstone.

1,112 3 1,142 0 Sandstone, occasional clay- 29 9

_ stone streaks.

Log, Drill Hole 3

Location: 920 feet N. and 265 feet W. of SE. corner, sec. 18, T. 18 N., R. 3 W.,

Seward Meridian, Houston, Alaska.

Elevation: Collar of hole - 249 feet.

.43 -i,,, -.- 43

6

5

11

2

5

7

0

7

4

6

9

10

11

6

0

11

4

6 Overburden, glacial sand,

gravel, and boulders.

Sandstone, dense, few included

pebbles and cobbles.

Claystone.

Claystone, soft.

Shale, dark.

Claystone, coaly.

Claystone, coaly streaks.

Claystone, coaly.

Claystone, dark, silty;

occasional coaly streaks.

COAL, bony.

Interbedded claystone, silty

claystone and siltstone.

Sandstone.

Claystone.

Sandstone, porous, fine to

medium, frequent clay bands.

Sandstone, dense, fine.

Claystone, silty, grading down

to siltstone.

COAL, bony.

Interbedded claystone and

silty claystone; occasional

sandy streaks.

Shale, carbonaceous.

Claystone.

Claystone, coaly.

Claystone.

Claystone, coaly.

1

3

1

27

3

6

5

18

2

43

5

1

1

1

6

0

11

6

3

3

2

5

7

9

2

3

1

1

7

6

11

5

8

2

10

1

5

Core loss, 3 ft. 4 in.

Core loss, 9 in.

Core loss, 1 ft., 2 in.

103

103

122

123

125

126

126

0

11

4

0

2

0

1

0

2

0

1

6
Ft.

126

127

127

133

142

145

177

181

182

196

199

217

224

233

236

243

244

244

256

258

260

333

337

FromIn.

Depth

6

0

11

5

10

8

3

Ft.

20

Hole 3 (Con.)

127

127

133

1

To42

145

177

181

182

196

199

217

224

233

236

243

244

244

256

258

260

333

337

386

In.

0

11

5

10

Claystone.

Claystone, coaly.

Claystone, dark; frequent coal

streaks.

Claystone to silty claystone,

occasional coaly fragments.

Interbedded coaly claystone

and carbonaceous shale.

Interbedded claystone, silty

claystone, and very fine

sandstone.

Interbedded claystone and

soft, porous sandstone.

Claystone, coaly.

Claystone, frequent silty and

coaly streaks.

Claystone, coaly.

Claystone, occasional silty

streaks.

Sandstone, fine.

Claystone.

Claystone, coaly.

Claystone, occasional thin

coaly streaks.

COAL, bony.

Shale, carbonaceous.

Claystone, occasional coaly

fragments and ironstone

nodules.

Claystone, coaly.

Shale, dark; few thin coaly

streaks.

Interbedded claystone, siltstone, and very fine sandstone.

Sandstone, soft.

Sandstone, soft, few pebbles

included.

ly

IThickness

5

9

2

31

4

13

3

18

6

9

3

6

1

11

2

1

72

3

49

Material Ft.

0 6

11

6

In. Remarks

Core loss, 1 ft.

Core loss, 1 ft. 2 in.

Core loss, 42 ft.

Bedding throughout is

0° to 150, with moderate crossbedding.

Regular bedding seldom

exceeds 5°. .-. . - - . -

- - . I . .

INT. BU.OF MINES.PGH* ,rA . 8485