GEOCHEMICAL/GEOPHYSICAL/GEOLOGICAL REPORT

Transcription

1 GEOCHEMICAL/GEOPHYSICAL/GEOLOGICAL REPORT OM SOIL GEOCHEHISTRY AND VLF-EM SURVEYS With Geological mapping^ OVER THE TAKU 2, DOEERTY, AND B.G.T. CLAIMS BREWERY CREEK, FORT STEELE AREA FORT STEELE.MINING DIVISION BRITISH COLUMBIA PROPERTY WRITTEN FOR SURVEYED BY WRITTEN BY DATED : 4.5 km NlOOE of Fort Steele, B.C. straddling Brewery Creek. : 49" 115" NW : N.T.S. 82G/12E : BOOMER RESOURCES LTD West Broadway Vancouver, B.C., V6J lw7 : TRANS-ARCTIC EXPLORATIONS LTD. # West Georgia Street Vancouver, B.C., V66 2T8 : David G. Mark, Geophysi # West Pender St Vancouver, B.C., V6C 2T : October 26, 1984 Engineering 8 Mining Geophysicists VANCOUVER, CANADA

2 SUMMARY CONCLUSIONS RECOMMENDATIONS i ii iii d d rrl INTRODUCTION AND GENE EMARKS... 1 PROPERTY AND OWNERSHIP... 2 LOCATION AND ACCESS... 2 PHYSIOGRAPHY... 3 HISTORY OF PREVIOUS WORK... 3 GEOLOGY 1. G.S.C. Maps Grid Mapping... 4 VLF-EM SURVEY: 1. Instrumentation and Theory Field Procedure Compilation of Data... 7 SOIL GEOCHEMISTRY: 1. Survey Procedure Testing Procedure Treatment of Data... 8 DISCUSSION OF RESULTS: (A) VLF-EM Survey General Comments Anomalies (B) Soil Geochemistry SELECTED BIBLIOGRAPHY GEOPHYSICIST'S CERTIFICATE AFFIDAVIT OF EXPENSES... 25

3 LIST OF ILLUSTRATIONS At Back of Report Property Location Map 1:8,600,000 MAP - 1 Claim Location Map 1: 50,000 2 In Back Pocket d Detailed Geology VLF-EM Survey Raw Data 1: 5,000 1: 5,000 VLF-EM Survey Data and Contours Fraser Filtered 1: 5,000 5 Soil Geochemistry Survey Gold 1: 5,000 6 Soil Geochemistry Survey Lead 1: 5,000 Soil Geochemistry Survey Zinc 1: 5,000

4 i SUMMARY Soil geochemistry and VLF-EM surveys as well as geological mapping were carried out over a portion of Boomer Resources Fort Steele property during June, The claims are located 4.5 km north of the Town of Fort Steele, British Columbia on Brewery Creek. Access to much of the property is easily gained by a twowheel drive vehicle. The terrain consists of gentle to steep slopes forested with light to moderately dense coniferous trees. The purpose of the surveys was to locate probable zones of gold, silver and/or sulphide mineralization both directly and through mapping the structure. Most of the property is underlain by argillites and quartzites of the Aldridge Formation. Similar rocks of the older Fort Steele Formation occur in the northwestern corner. Diorite dykes, sills or maybe flows strike northeasterly through the center of the property. The early development work consists of drifting on quartz veins within the Aldridge Formation. Nearby occurs the zinc-leadsilver-cadium deposit of the Kootenay King. VLF-EM readings and soil samples were taken every 50 meters on 50- and 100-meter separated northerly-trending lines. The VLF-EM data was then reduced, plotted and contoured. The soil samples were subsequently tested for 3 metals including gold, statistically analyzed, plotted, and contoured. Geological mapping was also done on the same grid.

5 ii CONCLUSIONS 1. The geological mapping on the property has indicated it to be mainly underlain by argillites and quartzites of the Aldridge Formation. There was also mapped carbonate breccia and amphibolite schist. Through the center of the property oc- curs a diorite dyke swarm within which the Dougherty adit occurs. 2. The VLF-EM has revealed mainly three anomalous zones, none of which correlates with soil geochemistry results. A fourth anomaly does correlate, however, with a gold anomaly (A). Around the Dougherty adit, occurs a complex VLF-EM anomalous zone that is probably reflecting lithological contacts. 3. The gold soil anomalies are small and spotty though most occur on the edge of the survey area. However, since gold in soils has little mobility, these anomalies are considered of exploration interest, especially considering the large sample spacing. 4. The main exploration interest within the survey area is anomaly G, the lead-zinc anomaly. The results are high and it has a good length of 1,000 m. Also, along the whole length, it is open to the west and the northern half is open to the east. The width is therefore unknown. Resides containing lead and zinc mineralization the causative source probably contains silver mineralization as well. 5. The soil results have indicated that there is likely no sub- stantial mineralizaiton occurring within or around the Dougherty adit.

6 iii RECOMMENDATIONS 1. The area to the north of the property should be staked since much of the interesting results occur in this area. 2. All gold anomalies that have been labelled should be de- tailed on a 10-m grid for, say 50 m, in all directions. 3. The soil sampling should be continued east, west and north of anomaly G, which the writer considers to be of strong ex- ploration interest. 4. Thorough prospecting should be conducted around anomaly G to locate the causative source (or sources) if possible.

7 GEOCHEMICAL/GEOPHYSICAL/GEOLOGICAL REPORT ON SOIL GEOCHEMISTRY AND VLP-EM SURVEYS With Geological Mapping OVER THE TAKU 2, DOHERTY, AND B,G.T, CLAIMS BREWERY CREEK, FORT STEELE AREA FORT STEELE MINING DIVISION BRITISH COLUMBIA INTRODUCTION AND GENERAL REMARKS This report discusses the survey procedure, compilation of data and the interpretation of VLF-EM and soil geochemistry surveys as well as geological mapping carried out over the Taku 2, Doherty and B.G.T. Claims during the period of June 12th to 23rd, The surveys were carried out by Trans-Arctive Exploratins Ltd. under the supervision of E.A. Dodd and the field supervision of Guy Royer, geologist, with the aid of D. Bowra. A total of 9.6 line km of VLF-EM survey were done and a total of 424 soil samples were picked up. The primary purpose of the VLF-EM survey was to delineate geo- logical structure as an aid in the exploration for gold mineral-

8 2 ization. That of the soil sampling was to locate gold mineraliz- ation directly. Besides gold, the samples were tested for lead and zinc. PROPERTY AND OWNERSHIP The property consists of three claims each overstaking the other and located within the Fort Steele Mining Division as shown on Map 2 and as described below: Claim Name NO. units Record No. Expiry Date B.G.T Oct. 27, 1984 Doherty Jan. 5, 1985 Taku Apr. 4, 1985 The expiry date shown does not take into account the surveys un- der discussion as being accepted for assessment credits. The claims are owned by Boomer Resources Ltd. of Vancouver, British Columbia. LOCATION AND ACCESS The property is located 4.5 km N1O"E of the Town of Fort Steele straddling Brewery Creek. The geographical coordinates are 49"40'N longitude. latitude and 115"36'W Access is easily gained to the propert! by travelling northnortheasterly out of the Town of Fort Steele along the Wild Horse River road. Just over 4 km and at a sharp turn in the road

9 3 on the immediate easterly side of Brewery Creek, one turns right (north-northeasterly) onto the Brewery Creek road. At this point occurs the property's southern boundary. Access roads occur through the claim group. PHYSIOGRAPHY The property lies to the west of the Rocky Mountain trench within the Purcell Mountains which are physiographic divisions of the Columbia Mountain System. The terrain consists of gentle slopes within the western part of the property to steep slopes within the northeastern corner. It lies across the Brewery Creek valley and on the southern slope of Lakit Mountain, Elevations vary from about 1,880 meters a.s.1. at the southwest corner of the property to,510 meters a.s.1. at the northeast corner to give an elevation difference of 630 meters, The main water source would be Brewery Creek. HISTORY OF PREVIOUS WORK The history of the property goes back to the 1904 when the main development work was done, probably mostly drifting, Since the present claims have been staked, no other work has been carried out. GEOLOGY 1, G.S.C. Maps The following is taken from the G.S.C. map by Leech.

10 4 The oldest rocks that occur in the area and on the property are those of the Precambrian Fort Steele Formation. It occurs in the northwest corner of the property and consists of white siliceous quartzite, grey, argillaceous quartzite, dark argillite, grey and black dolomitic and calcareous argillite as well as dolomite. The rest of the property is underlain by the Precambrian Aldridge Formation which overlies the Fort Steele Formation. It consists of similar rocks which are dark grey to black laminated argillite, grey siltstone, and quartzite, with rusty weathering. An earlier G.S.C. map by Rice also shows diorite sills and dykes of the Purcell Intrusives to strike northeasterly through the claims. The property contains the showing known as the Dougherty which Rice simply described as "quartz veins within the Aldridge Formation". He shows it occurring near the diorite sills, He does not describe any particular mineralization, but it is assumed to be gold. Leech, on his map, does not show the Dougherty. The closest main mineral property is the Kootenay King located about 6.5 km north of the Dougherty. Rice states that the "ore occurs in a bed of grey-green, dolomitic argillite, in the transition zone between the Fort Steele and Aldridge formations," "The ore is very similar in appearance to that of the Sullivan deposit. It consists essentially of fine-grained galena, sphalerite, and pyrite with little gangue other than unreplaced parts of the original sediments." 2. Grid Mapping The property was mapped 'by Royer as he carried out the VLF-EM

11 5 survey and the soil sampling. It is shown on Map 3. Most of the property is underlain by quartzites and argillites, probably of the Aldridge Formation. Near the northern boundary is an outcropping of carbonate breccia which could be of the Fort Steele Formation. There are also two outcroppings of amphibolite schist which could belong to either group. The beddings of the above-mentioned sediments strike northerly and northwesterly, and dip steeply to the west as well as the east. A swarm of northeasterly-striking diorite dykes were mapped through the center of the property. They are probably the Purcell Instrusives mapped by Rice, as mentioned above. The Dougherty adit is mapped within quartzite within the center of the dyke swarm. No mapping of the adit was undertaken by Royer. VLP-EM SURVEY 1. Instrumentation and Theory A VLF-EM receiver, model 27, manufacture by Sabre Electronic Instruments Ltd. of Burnaby, B.C. was used for the VLF-EM sur- vey. This instrument is designed to measure the electromagnetic component of the very low frequency field (VLF-EM), which for this survey is transmitted at 24.8 KHz from Seattle, Washington. In all electromagnetic prospecting, a transmitter produces an alternating magnetic field (primary) by a strong alternating current usually through a coil of wire. If a conductive mass

12 6 such as a sulphide body is within this magnetic field, a second- ary alternating current is induced within it which in turn in- duces a secondary magnetic field that distorts the primary mag- netic field, It is this distortion that the EM receiver meas- ures. The VLF-EM uses a frequency range from 16 to 24 KHz, whereas most EM instruments use frequencies ranging from a few hundred to a few thousand Hz, Because of its relatively high frequency, the VLF-EM can pick up bodies of a much lower conductivity and therefore is more susceptible to clay beds, electro- lyte-filling fault or shear zones and porous horizons, graphite, carbonaceous sediments, lithological contacts as well as sul- phide bodies of too low a conductivity for other EM methods to pick up. Consequently the VLF-EM has additional uses in mapping structure and in picking up sulphide bodies of too low a conduc- tivity for conventional EM methods and too small for induced polarization. (In places it can be used instead of 1.P.). How- ever, its susceptibility to lower conductive bodies results in a number of anomalies, many of them difficult to explain and, thus, VLF-EM preferably should not be interpreted without a good geological knowledge of the property and/or other geophysical and geochemical surveys. 2. Field Procedure The survey consisted of 9.6 line km of VLF-EM readings centered around the Dougherty adit. The base line was placed through the center of the Dougherty adit on a bearing of N70"E - S7O"W. It was extended for 800 m being well flagged with florescent orange survey flagging. The cross lines were run perpendicular to the base line at a 50- and 100-m spacing with the instrument readings taken at a 50 m in- terval facing towards the transmitter at Seattle.

13 7 3. Compilation of Data The VLF-EM field results were plotted on Map 4 at a scale of 1:5,000. They were then reduced by applying the Fraser-filter and the filtered results subsequently plotted on Map 5. The filtered data was plotted between actual reading stations. The positive dip-angle readings were then contoured at an interval of 4". The Fraser-filter is essentially a 4-point difference operator, which transforms zero crossings into peaks, and a low pass smoothing operator which induces the inherent high frequency noise in the data. Therefore, the noisy, non-contourable data are transformed into less noisy, contourable data. Another advantage of this filter is that a conductor that does not show up as a crossover on the unfiltered data quite often shows up on the filtered data. SOIL GEOCHEMISTRY 1. Survey Procedure The samples were picked up at 50-meter centers on the same N2OoW-S20"E lines as that for the VLF-EM survey. They were dug with a D-handled shovel at about a 15- to 20-cm depth. The horizon sampled was B. Samples were placed in brown, wet-strength, paper bags (gussett bags) with the sample number marked thereon. 2, Testing Procedure All samples were tested by Acme Analytical Laboratories Ltd, of Vancouver, B.C. The sample is first thoroughly dried and then pulverized in a ring pulverizer.

14 8 For the gold analysis, 10 grams of the sample was then fire-assayed with standard techniques. It was then leached with nitric acid and digested in aqua regia. It was next analyzed by the atomic absorption technique to a detection limit of 1 part per billion (ppb). For the lead and zinc, a 0.5 gram of the sifted material was put into a test tube with subsequent measured additions of perchlor- ic acid and nitric acid. The mixture was next heated for a cer- tain length of time. measured by atomic absorption. The parts per million (ppm) metal was then 3. Treatment of Data The values in ppm lead and zinc were grouped into equal logarithmic intervals. The cumulative frequency for each interval was then calculated and then plotted against the correlating interval to obtain a logarithmic cumulative frequency graph. The mean background value for each metal is taken at the 50% level. The sub-anomalous threshold value, (a term used by the writer to denote the minimum value that is not considered anomalous but still important as an indicator of mineralization) is taken at one standard deviation from the mean background value which is at the 16% level. The anomalous threshold value is two standard deviations away at the 2 1/2% level. The gold geochemistry data were not analyzed with a cumulative frequency graph due to the way the data were distributed. Rather, its statistical parameters were "eye-balled." As a result of the above, the. statistical parameters for each metal are shown in the following table with the sheet number that the geochemistry values for each of the metals were plot-

15 9 ted on. The maps are drawn at a scale of 1:5,000. Metal Au Pb Zn Map number G 8 9 Mean background value Sub-anomalous threshold value Anomalous threshold value The lead and zinc values are in ppm, and the gold, in ppb. DISCUSSION OF RESULTS (A) VLF-EM Survey 1. General Comments The major cause of VLF-EM anomalies, as a rule, are geologic structures such as fault, shear and breccia zones. It is therefore logical to interpret VLF-EM anomalies to likely be caused by these structural zones. Of course, sulphides may also be a causative source. But in the writer's experience, when VLF-EM anomalies correlate with sulphide mineralization, the anomalies are usually reflecting the structure associated with the mineralization rather than the mineralization itself. There is some variation in intensity from one VLF-EM anomaly to the next. This is not only due to the conductivity of a causative source, but also the direction it strikes relative to the direction to the transmitter. In other words, those conductors lying closer to the same direction as the direction to the transmitter (S70W in this case), can be picked up easier than those that are lying at a greater angle. Depending upon its con-

16 10 ductivity, a 'conductor may not be picked up at all if it is at too great an angle. However, on this particular survey are some VLF-EM conductors that have strong intensity and yet are at a low optimum direction to Seattle. This is therefore an indication of the causative source being a strong conductor. The survey has produced interesting results throughout the prop- erty, particularly the VLF-EM highs. These highs are of greater economic interest since they may be reflecting sulphides, frac- turing and/or alteration any of which could be associated with gold mineralization. The highs often are at points of intersec- tion of two or three conductors striking in two or three different directions, If the conductors are in fact geological struc- tures, then the points of intersection become amenable to miner- alizing fluids. 2. Anomalies There are three anomalous zones on the property. An easterly-striking zone of moderate strength occurs on the northern part of the property. The minimum length is 500 m and it is open on both ends. It has a northeasterly-striking arm in- dicating cross-structure, Around the Dougherty adit occurs a complex VLF-EM anomalous zone with the individual conductors striking northwesterly to northeasterly. It is quite possible, these conductors are reflecting contact zones. Nevertheless, the VLF-EM results indicate complex geology in this area. Towards the southern part of the survey area and the property is the third anomalous zone. Since there are only two survey lines, not much can be said, but the results appear to be reflecting

17 11 two easterly-striking conductors and possibly one northeasterly. (B) Soil Geochemistry Several anomalous zones that are worthy of exploration interest have been revealed by the soil geochemistry survey. These have been labelled by the capital letters A to H. In general, the correlation with VLF-EM conductors is poor. The samples were picked up at an interval no closer than 50 m. For gold, this can be a large interval. Therefore any anomalous results, even 1- sample highs, can be of interest. Anomalies A, B and C are strictly gold. Anomaly A is lineal in shape, strikes northeasterly, is at least 250 m long and is open to the northeast, This soil anomaly is the only one that correlates with a VLF-EM conductor, Anomalies B and C are 1-value highs occurring on the edge of the survey grid. Anomaly D is an easterly-striking gold anomaly that occurs on the side of a lead-zinc anomaly, The minimum length is 150 m being open to the east. Anomaly E is principally a 1-value gold anomaly, that occurs on a trend of northeasterly-striking sub-anomalous gold results. On this trend to the immediate northeast is a lead-zinc anomaly with a 250-m length that appears to be striking northwesterly. Anomaly F is an easterly-striking gold anomaly open at both ends with a minimum length of 600 m. The results are not that high but they are consistent, The eastern part of this anomaly contains minor lead and zinc results. The western part correlates with the strong lead-zinc anomaly labelled G.

18 12 Anomaly G is perhaps the most interesting anomaly within the survey area, It is a consistently strong anomaly with values as high as 74 ppm for lead and 319 ppm for zinc. The causative source not only likely contains lead and zinc mineralization but also, quite probably silver mineralization, The anomaly appears to be striking northerly in which case the length is 1,000 m. However, since it is open to the west along it whole length and to the east along the northern half the width is unknown. VLF-EM surveying was done in this area as is also the case for anomalies D, E and F. No Anomaly H is strictly a zinc anomaly that occurs at the southeastern part of the property, It appears to strike easterly, is open to the east, and has a minimum length of, say, 100 m. Certainly of interest is the fact that there was only a minor lead response in the soils around the Dougherty adit. The gold and zinc results were virtually flat. Respectf ly submitted, G m N & SURVEYS LTD. \ Geoppysicist. October r 1 4

19 13 SELECTED BIBLIOGRAPHY Leech, G.B., Geology Map - St. Mary Lake, British Columbia, Sheet 82 F/9, G.S.C. Map , Leech, G.B., Geology Map - Fernie (West Half), Kootenay District, B.C., Geological Survey of Canada, Map , Leech, G.B., Fernie Map-area, West Half, British Columbia; Geo- logical Survey of Canada, Paper 58-10, Rice, H.M.A. - Nelson Map-Area, East Half, British Columbia, G.S.C. Memoir 228, p , Rice H.M.A., Cranbrook Map-area, British Columbua, Geological Survey of Canada, Memoir 207, Schof ield, S. J. Geology of Cranbrook Area, British Columbia, Minister of M i n e s Reports p

20 14 GEOPHYSICIST'S CERTIFICATE I, DAVID G. MARK, of the City of Vancouver, in the Province of British Columbia, do hereby certify: That I am a Consulting Geophysicist of Geotronics Surveys Ltd., with offices located at # West Pender Street, Vancouver, British Columbia. I further certify: 1. I am a graduate of the University of British Columbia (1968) and hold a B.Sc. degree in Geophysics. 2. I have been practising my profession for the past 16 years and have been active in the mining industry for the past 19 years. 3. I am an active member of the Society of Exploration Geophysicists and a member of the European Association for Exploration Geophysicists. 4. This report is compiled from data obtained from VLF- EM, soil geochemistry and geological surveys carried out by Trans-Arctic Explorations Ltd., under the supervision of E.A. Dodd and under the field superivsion of Guy Royer, geologist, from June 12th to 23rd, I am not a shareholder of Boomer Resources Ltd. nor do I hold any interest in the B.G.T., Doherty or Taku 2 claims, nor will I receive any interest as a result of writing this report. October 26, 1984

21 15 AFFIDAVIT OF EXPENSES The VLF-EM and soil geochemistry surveys as well as geological mapping were carried out from June 12th to 23rd, 1984 over the Taku 2, Doherty and B.G.T. Claims, Brewery Creek, Fort Steele area, Fort Steele Mining Division, B.C. to the value of the following: FIELD: Supervisor, 5 days at $200/day $ 1, Instrument operators: geologist and assistant, 98 hours at $45/hour 4, Truck rental: 4x4 3/4 ton truck, 12 days at $llo/day (includes oil and gas) 1, Room and board, 2 men, 12 days at $100/day 1, Room and board, 1 man, 5 days at $50/day Survey supplies Instrument rental, VLF-EM, 21 days at $25/day $ 8, LABORATORY : Soil samples tested for gold, lead and zinc 424 soil samples $ 2, OFFICE: Geophysicist, 20 $45/hr Geophysical technician, 40 Drafting and printing Typing and photocopying $25/hr $ , , $ 3, Resp n lei c fully submitted, RCTIC EXPLORATIONS LTD. GRAND, TOTAL $14, S. Simpson Gen 1 Manager RicqT

22 d PROPERTY Islands rl I s l a n d L rl Pacific Ocean 12 TAKU 2, DOHERTY, B.G.T. CLAIMS Km. IO0 0 IO0 200 Mi MAP I BRAD'S DRAFTING SERVICE

23 Y I //so 36' BOOMER RESOURCES LTD. TAKU 2, DOHERTY, B.G.T. CLAIMS BREWERY CREEK, FORT STEELE AREA, B.C. I I 2 KILOMETRES. CALE. I' 50,000 OATE: MAP1 HTS Aug G/12E

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