Cominco Ltd. Exploration Assessment Report 1980

Home , Coldwater Beds

COMINCO LTD.

EXPLORATION WESTERN DISTRICT

NTS: 921 13E/14W

ASSESSMENT REPORT

1980 GEOLOGICAL AND GEOCHEMICAL REPORT ON THE

ASH 1. 2 and 3 MINERAL CLAIMS

IN THE HAT--- CREEK AREA KAMLOOPS MINING DIVISION, BRITISH COLUMBIA

MINERAL RESOURCES BRANCH ASSESSMENT REPORT

22 MAY 19.81 R.J. SHARP TABLE . OF. CONTENTS

Page SUMMARY.' ...... 1 INTRODUCTION ...... 1 PROPERTY AND OWNERSHIP ...... 2 LOCATION AND ACCESS ...... 2 SUMMARY OF WORK ...... 2 DETAILED TECHNICAL DATA AND INTERPRETAION .... 2 Regional Geology ...... 2 Detailed Geology ...... 3 Unitl...... 3 Uni t-2 : ...... 3 Unit3...... 3 Structural Geology ...... 4 MINERALIZATION ...... 4 GEOCHEMICAL SURVEY ...... 4 Field and Analytical Techniques ...... 4 RESULTS ...... 5 DISCUSSION OF RESULTS ...... 6 CONCLUSIONS AND RECOMMENDATIONS ...... 7 REFERENCES ...... 7

ATTACHMENTS Appendix A: Exhibit "A" . Itemized Cost Statement Appendix B: Author's Qualifi cati ons

Figure 1: General Location Map Figure 2: Location Map 1.250. 000 Scale Figure 3: Claim Outline Map Figure 4: Geology and Geochemistry Figure 5: Geochemistry .Au Figure 6: Geochemistry . Ag Figure 7: Geochemistry . As Figure 8: Geochemistry . Cu Figure 9: Geochemistry . Pb Figure 10: Geochemistry . Zn Figure 11: Regional Geochemistry

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EXP LO RAT I ON WESTERN DISTRICT

NTS: 921 13E/14W 22 May 1981

ASSESSMENT REPORT

1980 GEOLOGICAL AND GEOCHEMICAL REPORT ON THE

ASH 1, 2 and 3 MINERAL CLAIMS IN THE HAT CREEK AREA

KAMLOOPS MINING DIVISION, BRITISH COLUMBIA

SUMMARY The Ash claims are located 12 km west of Cache Creek British Columbia and cover gold-silver-arsenic-mercury anomalies in soil, silt and rock sampl es. Work in 1980 consisted of silt, soil and rock geochemistry and geological mappi ng.

This work confirms the presence of anomalous gold values in soils and rocks of Tertiary Co ldwater Beds (sandstone and conglomerate ) intruded by a rhyolite dome.

INTRODUCTION This report describes the geology, rock, soil and silt geochemistry on Cominco's ASH claims, 12 krn west of Cache Creek, Br- tish Columbia, (see figures 1 and 2 for location). The report is based upon field investi- gations by R.J. Sharp and assistant A.D. Croft during the period May 16 to May 20, 1980 and by R.J. Sharp and M.L. Serack during the period Octo- ber 8 to October 15, 1980. The work was supervised by R.Y. Watanabe. The program this year consisted of geological mapping, silt, soil and rock geochemistry. Soil samples were collected along grid lines, silt samples were collected on all major drainage channels crossing the property and rock samples were collected from rock outcrops on the claims. Data are presented on a scale of 1:10,000. Assessment ReportjAsh Mineral C1 aims/ 22 May 1981lPage 21

The Ash claim group is made up of three claims comprising 55 units, all owned 100% by Cominco Limited (see Figure 3). This report files credit for all three Ash claims which are listed below: Claim Name Record Number Due Date Ash 1 2570 May 2, 1981 Ash 2 2571 May 2, 1981 Ash 3 2572 May 2, 1981 Legal corner posts, identification posts, and claim boundaries were located by chain and compass surveying and are plotted on a 1:10,000 scale topographic map.

LOCATION AND ACCESS . The property is situated in the Kamloops Mining Division at 50’48’N and 12l03O’W, NTS 921 13, approximately 12 km west of the town of Cache Creek, British Columbia. Access is by road from Cache Creek. The claims are situated in low mountainous terrain (900 to 1500 m above sea level) in the Trachyte Hills. .Open forests of pine cover most of a the claims; in creek valleys,willow and spruce thickets are common. SUMMARY OF WORK

A geological map of the Ash Claims was prepared using an enlarged 1:50,000 scale topographic map to provide a base map of 1:10,000 scale. A total of 216 samples weye collected on a grid tied irlto the claim grid, of these samples 11 were analyzed 3 times for gold and 14 were analyzed twice. The repeat analyses were made to test the reproducability of the gold analyses obtained from the claim group. In addition, 27 silt samples and 43 rock samples were analyzed. All samples were assayed for gold, silver and arsenic, selected samples were run for copper, lead, z inc , f 1 uori ne , mercury, molybdenum and tungsten.

DETAILED TECHNICAL DATA AND INTERPRETATION

Regional Geology: The regional geology of the area surrounding the Ash Claims has been described by Duffel1 and McTaggart (1952) and by Church (1977). The oldest rocks on the claim group are Permian and belong to the Cache Creek Group; they are composed of metamorphosed cherty silt- stone, basaltic tuff and serpentine. Early Tertiary sandstone and conglomerate belonging to the Coldwater Beds overlie the Cache Creek Group. A mass of fine-grained rhyolite, ‘2 km in diameter, cuts the Coldwater Beds in the southern portion of the claim group.

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Detailed Geology: A map of the detailed geology of the claim group is 0 shown in Figure 4. The rock types are simple and distinct; the basement rocks are the Cache Creek Group which are overlain by sandstone and conglomerate of the Coldwater Beds into which a rhyolite body has been emplaced. These three rock types are described in the following section. Unit 1: Cache Creek Group The Cache Creek Group is exposed in several outcrops in the northeast portion of the claims. Metabasaltic tuff, siliceous metasediments and chert plus serpentine comprise the exposures of Cache Creek Group on the Ash claims. An altered serpentine mass, outcropping 500 m west of Gallagher Lake, contains dolomite veinlets (5 mm wide) and chalcedony veins (2 mm to 2 cm wide). Black chert pebbles are very abundant in the overlying Coldwater Beds and were most likely derived from the Cache Creek Group. 'No geologic contacts were observed on the property but the great difference in ages between the Cache Creek Group (Permian) and Tertiary sedimentary and volcanic rocks suggests either structural or unconformable contacts exist.

Unit 2: Coldwater Beds The unit described here as "Coldwater Beds" is identical to that of Church's (1977) and does not include any of the "Hat Creek Coal Formation" or the "Medi ci ne Creek Formati on". The Col dwater Beds exposed on the cl aims a are lithologically similar to those underlying the Hat Creek area to the west and are described by Church (1977) as being "firmly indurated brown sandstones and conglomerates". Layers, up to 1 m thick, composed domi- nantly of pebbles are interbedded with medium to coarse-grained sandstone. The pebbles are rounded to subrounded, up to 5 cm in diameter but aver- aging 2 cm in diameter. The most common pebble lithology is black chert (65%; with 10% white quartz and 5% felsitf: or rhyolite pebbles composing 80% of the layer with the remaining 20% made up by sandstone matrix. The black chert pebbles are derived from the Cache Creek Group, the rhyolite or felsite pebbles are probably derived from the Spences Bridge Group of Cretaceous rhyolites exposed to the south of the Hat Creek area.

Unit 3: Rhyolite The rhyolite unit on the claim group is composed of'a fine-grained rhyo- litic rock mass about 2 km in diameter, and forms the highest point on .the claim group. Typically the rhyolite is a homogenous, fine grained rock occasionally with a bimodal character containing small phenocrysts of quartz, sanidine, biotite or plagioclase. The phenocrysts are rarely over 1 m in diameter and seldom compose more than 5% of the rock. Quartz, sanidine, and biotite are most easily seen in fresh specimens whilst plagioclase is more visible in glacially polished outcrops.

Rhyolite is usually massive and featureless, except for sections of highly jointed lava. The highly jointed rhyolite is believed to be a cooling phenomena because fractures cross-cut phenocrysts which indicates fract- 0 uring occurred after crystallization. I'n the southeastern part of the

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claim group a small area about 1.5 m thick and 5 m long shows vesicu- lation and a crude layering that may be fl%w banding. No other textures were observed to indicate that the rhyolite was extruded hence it is concluded that the rhyolite represents an intrusive dome.

Structural Geology: The predominant structural trend on the Ash claims is NW-SE. Topographic linears and traces of faults run in the NW-SE direction as do the strike of most bedded rocks. Structural measurements made on the Coldwater beds show the strata to strike SSE to S (135' to 174O) and dip from 2Oo-5O0 westerly. Radial drainage patterns surround the rhyolite dome and indicate normal faulting assoicated with emplacement of the intrusive body. North-south trending faults cross-cut the rhyolite and suggest that some movement occurred along the major normal faults in the area after intrusion of the dome.

The structural geology of the rock units on the Ash claims supports Church's (1977) contention that the Hat Creek area is a fault-bounded graben. The Ash claims lie on the upper eastern portion of the graben and most deformation has been tensional whereby blocks have downdropped along N-S trending normal faults.

MI NE RAL I Z AT I ON

No mineralization was observed in outcrop or. float. The only evidence of gold mineralization is found in the results of the geochemical sampling work. There are no pyritic or silicified zones evident in either the rhyolite dome or the Coldwater Beds,however,the contact zone between these two units is obscured by overburden. The contact zone may be the source of several kezk gold anorfinliesnear the north-east margin of the rhyolite dome; the geochemical anomalies are discussed in the next section.

GEOCHEMICAL SURVEY FieTd and Analyt.ica1 Techniques

The geochemical survey consisted of silt, soil, and rock sampling on the Ash 1, 2 and 3 claims. Silt samples were taken from the silts of major drainage courses crossing the property. Soi 1 samples were collected along a grid tied into the claim boundary lines. Soil sample spacing was 200 m and samples were taken from the B horizon 5-25 cm below surface. Rock samples, consisting of 2 kg amounts, were collected from represen- tative outcrops over a 1 m interval; only fresh material was sampled.

All sarnple.sites were marked with orange flagging. Soil and silt samples were stored in large kraft envelopes. Rock samples were stored in heavy plastic sample bags. Assessment Report/Ash Mineral C1 aims/ 22 May 1981/Page 5/

The soil and silt samples were dried, the rock samples were crushed; the sample material was then sieved to minus 80 mesh, and the fines retained for analysis. Copper, lead, zinc contents were determined by atomic absorption spectrophotometry of solutions obtained by 20% nitric acid digestion of sieved material. Arsenic was released from the samples by pyrosulfate fusion and its concentration was estimated colorimetri cal ly. Gold values were obtained by aqua regia digestion of sample material , followed by solvent extraction and atomic absorption spectrophotometry. Molybdenum and tungsten were released from samples by nitric-perchloric acid digestion and pyrosulphate fusion, respectively. The contents of both elements were estimated colorimetrical ly with dithiol . Mercury was analysed using a hot leach in a mixture of nitric and perchloric acid. The mercuric ions in the sample solutions were reduced and the resulting elemental mercury flushed out by air and passed through an atomic absorption mercury meter. Fluorine analyses were obtained using the specific ion technique. All analyses were carried out by the Comi nco Exploration Research Laboratory i n Vancouver , B . C.

RESULTS

The concentration ranges, geometric means, and anomaly thresholds for gold, silver, arsenic, copper, lead, zinc and molybdenum are listed in Table I. Threshold values were estimated on the basis of probability plots and histograms. Also listed in Table I are the ranges for mercury, fluorine and tungsten with a threshold value estimate based on average abundances of the elements for igneous and sedimentary rock types common om the Ash claims. Sample sites and geochemical results are plotted in figures 4,5,6,7,8,9,10 and 11.

TABLE_- --- I DATA DISTRI BUT1 ON PARAMETERS ASH GEOCHEMICAL SURVEY Es timated Anomaly Element Range Geometric Mean Thres hol d

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chemical results and anomalies for Au, Ag, As, Cu, Pb, and Zn respectively. Figure 11 is a plot of silt geochemistry taken from creeks draining the claim group.

DISCUSSION OF RESULTS Interest in the area stems from high gold values obtained in both the silt (3300 ppb Au) and heavy mineral (1100 ppb Au/69 ppm As) fractions of a stream sediment sample collected in 1979. The Ash claims were staked in early 1980 and a stream sediment survey was undertaken to trace the source of the gold. Two Au anomalies were defined, one on the main part of Gall- agher Creek (56 ppb Au, see figure 11) the second on the south fork of the same creek (224 ppb Au, see figures 4 and 5). A modest scale soil and rock sampling program was then carried out to locate the bedrock source of the gold. Two Au anomalous areas were defined, one lies near the northern contact of the rhyolite dome and Coldwater Beds, the second lies southwest of the rhyolite dome - Coldwater Bed contact. The north contact ar2a (see figure 4) yielded the highest results forgold in soils but upon duplicate and triplicate geochem ana’lysis (of the same sample material - see figure 5) no anomalies were repeated. This suggests that the gold is in a particulate form and the ‘nugget effect’ strongly influences the sample result (i.e. the probability of the analyst in the lab picking a scoop of material bearing a gold grain is generally low). a The southwest contact area (see figure 4) shows two gold anomalies, one weak anomaly from a soil sample (60 ppb Au), another rather strong anomaly in a rock sample (940 ppb Au) . Both anomalies are spacially separate from other anomalous gold samples but because sample density is low in this area significance must be attached to them. The soil Au anomaly occurs near the volcanic-sedimentary contact whilst the rock Au anomaly lies about 600 m from it. The mck sample is a medium grained brown sandstone from the Coldwater Beds and does not appear mineralized or to differ sig- nificantly from other rocks in the Coldwater Beds.

Three weak silver anomalies (0.5 - 0.7 ppm) occur in the northwest contact area (figures 4 and 6); one anomaly (0.7 ppm) is coincident with a gold (80 ppb) anomaly. The values are very low and these anomalies are not viewed as significant.

Arsenic anomalies (see figures 4 and 7) are weak in the rhyolite (16-19

’ ppm) and commonly weak in the Coldwater Beds but several high values (137 and 720 ppm) were obtained from sandstone samples. The reason for high arsenic contents of the two rock samples is not readily apparent but may be attributed to detrital arsenopyrite. One weak mercury anomaly (178 ppb) in a rock sample of Coldwater sandstone was found in the northern part of the claim group. This sample occurs in close proximity to the Coldwater Beds - Cache Creek Group contact which may be a fault. A mercury enrichment near the fault may exist; this may be a checked by additional mercury analyses of samples collected near the fault.

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One weak molybdenum anomaly (3 ppm) was reported in a silt sample from Gallagher Creek. A second weak (3 ppm) molybdenum anomaly in a rock sample was found in the southern portion of the claims. Because the values are low and isolated, the anomalies are not rated as significant. Three weak lead anomalies (5 ppm) in soil samples and one weak anomaly (6 ppm) in a rock sampleweredefined. In addition three weak zinc anomalies (160 - 183 ppm) were found. These anomalies occur in the same general areas (see figures 4,9, and lo), but are weak and not coincident with either gold or silver anomalies hence are considered to be insignificant.

No copper or tungsten anomalies were found. Copper values ranged from <1 - 72 ppm (see figure 8) and tungsten values ranged from <2 - 2 ppm (see figures 4 and 11).

CONCLUSIONS AND RECOMMENDATIONS Significant gold anomalies occur in soils in the northern contact area (figure 4). A1 though rep1 icate analyses returned no anomalous values from previously high Au bearing sample material one new anomaly was pro- duced from previously low Au bearing material. This suggests that gold is indeed present in the rocks and soils but is in a particulate form and possibly of a grain size that induces the "nugget effect" during lab analyses.

It is recommended that addition soil and rock sampling be undertaken in the north contact area to further test for gold. A larger sample size should be analyzed to reduce the influence that discrete gold grains have upon the analytical results.

REFERENCES

Church, B.N. (1977): Geology of the Hat Creek Coal Basin in Geology in B. C. , Mi ni stry of Mines and Petrol eumResources , Province of B.C.

Duffel1 , S & McTaggart, K.C. (1975): Ashcroft Map-Area, British Columbia, Geol. Surv., Canada, Mem. 262. . Sinclair, A.J. (1976): Applications of probability graphs in mineral exploration. Spec. Vol. 4, Assoc. of Expl. Geochemists, 95 p.

Report by:

RJS/s kg Endorsed by : e Di s t ri buti on Mining Recorder (2) klestern District( 1) Approved for RJSIRYW (2) Re1 ease by :

Western Di strict APPENDIX "A"

E XH IB IT "A"

STATEMENT OF EXPENDITURES ON THE ASH 1. 2. 3 MINERAL CLAIMS for 1980- 1981

GEOLOGY Salaries: R.J. Sharp - May 16 to 20,1980 (5 days @ $148.72/day)= $ 743.60 October 8 to 15,1980 (8 days @ $148.72/day)= 1189.76 Report writing and drafting (5 days @ $101.20/day) 506.00

A.D. Croft - May 16 to 20,1980 (5 days @ $80.96/day) 404.80

M.L. Serack- October 8 to 15,1980 (8 days @ $107.50/day) = 860.00 Drafting (3 days (3 $73.15/day) 219.45 Expense Accounts

Accommodation and food for crew in Cache Creek (13 days) = 1224.30

GEOCHEMISTRY (Analyses done at Corninco's Vancouver Lab)

Soils: 180 (3 8.70 = 1566.00 21 I3 1.95 = 60.45 5 @ 4.20 = 21 .oo 36 (3 3.75 = 135 .OO

Rocks : 29 cd 11.95= 346.55 14 @ 8.75= 122.50

Silts: 24 I3 15.15 = 363.60 1 @ 8.70 = 8.70 1 @ 10.20 = 10.20 1 (3 11.70 = 11.70

Total Geochemistry: 2645.70 TRANSPORTATION Truck Rental (13 days @ $944/mo.) 409.07 Truck Fuel and Oil 190.00

GEOLOGICAL SUPPLIES Sample bags, flagging, drafting paper, notebooks 100.00

TOPOGRAPHIC MAP (1 : 10,000 Scale) 55.00

.. e FRE I GHT (Shipping Samples to Lab) 35.00 TOTAL EXPENDITURES : 5 8,583.68 APPENDIX "B"

STATEMENT OF QUALIFICATIONS

I ROBERT J. SHARP, OF THE CITY OF VANCOUVER, BRITISH COLUMBIA, HEREBY CERTIFY :

1. THAT I AM A GEOLOGIST RESIDING AT 2764 WEST SECOND AVENUE, VANCOUVER, BRITISH COLUMBIA WITH A BUSINESS 'ADDRESS AT 700-409 GRANVILLE STREET, VANCOUVER, BRITISH COLUMBIA.

2. THAT I GRADUATED WITH A B.SC. DEGREE IN MINERAL ENGINEERING FROM THE UNIVERSITY OF ALBERTA IN 1975.

3. THAT I GRADUATED WITH A M.SC. DEGREE IN SEOLOGY FROM THE UNIVERSITY OF ALBERTA IN 1980.

4. THAT I HAVE PRACTISED GEOLOGY WITH THE UNION OIL COMPANY OF CANADA LTD. , MINERALS DIVISION, IN CALGARY ALBERTA FROM 1978 TO 1980.

5. THAT I HAVE PRACTISED GEOLOGY WITH COf~lINC3LTD. FROM 1980 TO 1981.

6. THAT I AM REGISTERED AS AN ENGINEER-IN-TRAINING WITH THE ASSOCIATION OF PROFESSIONAL ENGINEERS, GEOLOGISTS AND GEOPHYSICISTS OF THE PROVINCE OF ALBERTA: MEMBER NUMBER 18311.

DATED THIS 25th DAY OF MAY, 1981, AT VANCOUVER, BRITISH COLUMBIA.

Signed: / Robert J/ Sharp

25 MAY 1981 hwn by: (Traced by: I 1

LOCATION MAP