GEOLOGICAL BRANCH ASSESSMENT REPORT ON THE PAM 1-5 CLAIMS DU PONT OF CANADA EXPLORATION LIMITED GEOLOGICAL AND GEOCHEMICAL REPORT

Transcription

1 DU PONT OF CANADA EXPLORATION LIMITED GEOLOGICAL AND GEOCHEMICAL REPORT ON THE PAM 1-5 CLAIMS LIARD MINING DIVISION LAT. 57'46'N, LONG. 127'45'W NTS: 94-E-13 E&W OWNER OF CLAIMS: OPERATOR: Du Pont of Canada Exploration Limited Du Pont of Canada Exploration Limited Author : H.J. Copland Date Submitted: 1982 October n GEOLOGICAL BRANCH ASSESSMENT REPORT

2 TABLE OF CONTENTS Paqe No. SUMMARY INTRODUCTION LOCATION AND ACCESS TOPOGRAPHY AND VEGETATION PROPERTY DEFINITION PREVIOUS WORK PERSONNEL GEOLOGY Regional Geology Local Geology Mineralization i.rr GEOCHEMISTRY Procedure Results TRENCHING CONCLUSIONS AND RECOMMENDATIONS COST STATEMENT REFERENCES QUALIFICATIONS APPENDIX A - Laboratory Procedures APPENDIX B - Calculation of Probability Graphs

3 LIST OF FIGURES Following Page No. Figure 1 General Location Map Figure 2 Index Map Figure 3 Regional Geology Figure 4 Au-Ag-As Geochem. Probability Curves Figure 5 Cu-P b-zn II $1 (I LIST OF DRAWINGS AR AR.82-5 AR.82-6 PARK Claims Geology PARK Claims Geology and Trenches PARK Claims - Trench Detail

4 SUMMARY The PARK 1-5 claims are located 130 km southeast of Dease Lake, British Columbia. The claims are owned and operated by Du Pont of Canada Exploration Limited. Work in the summer of 1982 involved trenching across a gold, silver and copper soil anomaly identified in the previous year. Sampling of the trenches reveals a high degree of enhancement of silver, copper and especially gold in the soils as compared to the underlying bedrock. The anomalous zone is concentrated over a band of highly silicified rock. INTRODUCTION During August 1982, assessment work consisting of trenching and subsequent soil and rock sampling was performed on the PARK claims, located in north-central British Columbia. The purpose of this year's work was to reach and sample bedrock below an auriferous soil anomaly. LOCATION AND ACCESS The PARK 1 to 5 claims are located 130 km southeast of Dease Lake, British Columbia within the Liard Mining Division, NTS: 94~/13 (Lat. 57'46'N, Long. 127O45'W). Access to the claims is via helicopter from the Strudee Valley airstrip which lies 75 km to the southeast. The major supply centre for the area is Smithers which lies 260 km south of Sturdee Valley. See Figures 1 (General Location map) and 2 (Index ~ ap). TOP OGRAP HY AND VEGETATION The PARK claims are located within the Stikine Ranges of the Cassiar Mountains. Elevation ranges from a high of 2000 metres in the northeast and southeast to a low of 1220 metres in a valley in the east central portion of the claims. The area is characterized by broad grassy valleys with scattered stands of spruce trees and shrubs. The slopes above 1500 metres are generally treeless and covered with grasses. PROP ERE' DEFINITION The PARK claims consist of five claims totalling 63 units. Figure 2. I See

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6 ... -ZMPPX MAP ~ R X CLAIMS

7 Claim Name # of Units Record # Tag # Date Recorded PARK July 25 PARK July 25 PARK July 25 PARK Oct. 13 PARK Oct. 13 PREVIOUS WORK There is no indication of previous work being conducted on the property, although Cominco Ltd.'s BILL claims adjoin the property to south and west. PARK 1, 2 and 3 were staked in July 1980 as the result of an auriferous stream sediment sample. Follow-up work in the summer of 1981 resulted in the locating of a zone of auriferous soil and rock on PARK 1. Subsequent to this in October 1981, PARK 4 and 5 were staked adjoining PARK Property work during 1982 consisted of placing eleven trenches across the auriferous soil zone of PARK 1 in an attempt to reach the bedrock source of the anomaly. PERSONNEL 1982 August 2 to October 15: H. Copland (~eologist) B. Yamamura (Jr. Geological Assistant) E. O'Brien (Jr. Geological Assistant) B. Dieter (Blaster) B. Richard (Blaster's Assistant) GEOLOGY Regional Geology The PARK claims lie near the eastern edge of the Intermontane Belt. Cambrian and older sedimentary and metamorphic rocks of the Omineca Crystalline Belt lie 90 kilometres to the east of the PARK claims. The oldest rocks in the area are a sequence of low grade metamorphosed sedimentary and volcanic rocks rela7 ted to the Upper Paleozoic Asitka Group, found in other areas. Thorstad (1980) has dated this sequence as Mississippian, on the basis of crinoids and conodonts found in the dolomitic. members.

8 Geologic sketch map showing distribution and major structuml elements of Upper Paleozoic rocks and relations to other rocks in the northwest'toodoggone map area.

9 To the south of the Stikine River, Lower Jurassic Toodoggone volcanic rocks and Upper Cretaceous sedimentary rocks of the Sustut Group dominate. To the east of the Toodoggone volcanic rocks small zones of Upper Triassic Takla Group and Lower Jurassic Hazelton Group crop out. North and east of the Stikine River Valley, near the claims, large plutons of Jurassic quartz monzonite and dioritie mark the boundary of the Intermontane and Omineca Belts. See Figure 3, Regional Geology. Local Geology PARK 2, 3 and the southermost area of PARK 1 are underlain by Asitka group metamorphosed volcanic rocks. These have been intruded by small plutons and dykes of igneous rocks ranging in composition from quartz monzonite to diorite. The northwestern corner of PARK 1 contains andesites and dacites probably belonging to the Triassic Takla Group. These units show varying degrees of silicification and pyritization and will be discussed further in a later section. The following is a brief description of lithologies observed on the PARK claims as described by Drown (1981). "i) Phyllite (Unit 1 ~ ) Occurring within PARK 1 and 3, this unit is greygreen in colour, is locally weakly chloritized and exhibits a well developed schistosity. Within the schistose layers occur frequent quartz lenses and sweats up to 10 cm wide. These quartz bodies often contain chalcocite, galena, and pyrite in massive blobs. Significant Ag values (321 ppm) are reported from these sulphide blobs. Minor carbonate alteration occurs in PARK 3 associated with disseminated pyrite and quartz sweats along foliation in the phyllite. The attitude of the phyllites is northwesterly with shallow northeasterly dips creating several dip-slope type hills and hogsback ridges. ii) Chert (Unit 1) This unit occurs extensively within PARK 2 and in the northeastern area of PARK 1. It consists of chert with lesser tuf faceous sediments and minor andesitic volcanic rocks. The chert is typically black to grey in colour and massive, although tuffaceous locally. Occasional quartz-calcite I

10 stringers cut the chert at numerous attitudes. The general trend of this unit appears to be northwesterly with shallow dips to the northeast. The emplacement of intrusives to the north has led to the development of intense pyrite alteration and bleaching of the chert creating spectacular gossans. iii) Andesite-Dacite (Unit 2) This unit consists of fine to medium grained, green to beige volcanics, possibly of the Takla Group. These rocks are in part porphyritic with anhedral plagioclases up to 1 cm long. The groundmass is mostly green except where alteration has changed it to a rusty beige colour. Frequent quartz stringers and veins cut the volcanics at unknown attitudes. Up to 10% disseminated pyrite has led to a significant gossan which is traceable for m in an east-northeast direction in PARK 1. At least two northwesterly trending faults offset the gossanous zone. The attitude of the volcanics appears from the style of hogsback ridge in PARK 1 to be east-northeast, dipping to the southeast at approximately 30". Volcanic rocks of this unit do not appear elsewhere on the PARK claims. iv) Diorite (unit 3) This unit occurs within the northeast and northcentral sectors of PARK 1 and is in contact with units 1 and 2. It is medium grained, pink and green and weathers to a pink/buff colour. Several fine to medium grained dykes, dark grey in colour, containing epidote intrude the chert (unit 1). It is unknown whether the dykes are offshoots of the main diorite body or separate entities. v) Quartz Monzonite-Granodiorite (Unit 4) This unit appears to exhibit several phases varying from rhyolite to granodiorite. It is fine to medium grained with chloritized mafics, minor pyrite and is strongly clay-quartz-pyrite altered along contacts with country rocks exhibiting several spectacular gossans. Alteration appears to be completely due to the contact with country rocks showing no veining or sulphide mineralization other than disseminated pyrite. I

11 In 1982, work concentrated on a 200 x 200 metre gossanous zone in the west central portion of PARK 1. Very little outcrop occurs in this gossan. It is composed mainly of an orangybeige soil with small rock fragments. Trenching was necessary to reach bedrock. Rock units observed in trenches in this zone can be classified into five basic units: 1. Andesite This unit is similar to that described previously (unit 2), and is the most extensive lithology of the area. The andesite has varying degrees of silicification and pyritization. Silica in the form of minor small quartz veinlets and partial replacement of the matrix increases towards the central zone of the gossan. Minor disseminated pyrite and pyrite cubes to 5 mm in size, comprise up to 20% of the rocks in several areas, 2. Tuff The tuffaceous rock occurs in two trench locations over a small portion of each trench. The rock is characterized by felsic and maroon angular fragments less than 1 cm in size and comprising 5-15% of the rock. Small rounded quartz eyes less than 2 mrn in size make up approximately 5% of the rock. Anhedral, clay altered feldspars averaging less than 5 mm in size make up 30-50% of this rock unit. 3. Chert Very fine-grained black chert containing pyrite nodules less than 1 cm in size and pyrite stringers occurs in the southern area of the gossan. This chert is probably related to Unit (1) described earlier. The small chert beds are intercalated with pyritiferous andesites. Silicified Zone A zone of highly silicified rock occurs as a downslope trending band through the gossan. The exact width of this zone is not known but it appears to average 10 to 15 metres over a distance greater than 150 metres. The core of this zone consists of a light grey to white fine-grained quartz containing minor pervasive pyrite cubes less than 1 m in size. Outward from this core, the rock grades to a silici+ fied andesite. The exact nature of the contact is not clear as it was poorly exposed in the trenches.

12 5. Magnetite - Quartz Sinter Zone Exposed at the surface in the central portion of the gossan is a distinctive sinter zone. The zone is made up of angular blocks to 1 emtre in size of a breccia composed of quartz fragments 0.5 to 3 cm in size cemented by an ironmanganese oxide. Two metres below the surface of this sinter occurs a zone of massive magnetite altering to a deep red clay. The magnetite zone is highly weathered and fractured and crumbles when touched. It is exposed over a length of 4 metres in one of the trenches. Mineralization Only minor amounts of mineralization have been noted on the property to date. Pyrite ranging from traces to 20% is present in quartz and andesites on PARK 1. This pyrite accounts for the prominent gossans observed on the slopes. As discussed previously, a zone of massive magnetite was found in one of the trenches running across a siliceous sinter zone. Small isolated zones of chalcocite-galena have been noted by Drown (1981). GEOCHEMISTRY Procedure A total of 123 soil and 62 rock samples were collected from trenches in the west central portion of PARK 1. Soil samples were taken at a 2 metre spacing along the length of the trench before blasting, and again once the trench was completed. The soils were placed in kraft sample bags along with a tag denoting the sample number. Where rock was encountered in a trench, rock chip samples were taken over 2 metre intervals. All samples were shipped to Min-En Laboratories, North Vancouver, B.C. for preparation and analysis. The soils were dried and sieved to -80 mesh and tested for Cu, Pb, Zn, Ag, As and Au. The rock samples were crushed to -100 mesh, assayed for Cu, Pb, Zn, Ag, As and Au and analyzed geochemically for Cu, Pb, Zn, Ag, Hg, As, Au and Sb. For details on analyzing procedures, see Appendix A. Results Soil and rock sampling in 1982 was restricted to the anomalous Au-Ag-Cu zone identified in Results from 1982 reflect this bias in sampling. All elements show an above background trend for the area.

13 R''Z 111.~11 I i:~. LL Pl4OlJAUlLlTY X 2 LOG CYCLES CLSL~~ co In

14 I'I(0IIALIILITY X 2 LOG CYCLES f('be nl.o, I.I.L C~SLII CO. 1" " : A

15 Soil samples from 1981 have been interpretated by Drown (1981). These results have been taken to represent normal background for the area soil sample results have been analyzed using the method described by Lepeltier (1969). For details on this method, see example calculation in Appendix B. These results have been graphed and are shown in Figure 4 for Au, As, Ag and Figure 5 for Cut Pb, Zn. A comparison of the background and threshold (anomalous) values for the general region (1981) and the gossanous zone (1982) is shown in Table 1. Background Au Ag As Cu Pb Zn Thresh -old Table 1: Background and Threshold Values in Soils [~ll values ppm except Au (ppb)] No. Samples: 1981:188, 1982:123. As seen in Table 1, values for Au, Ag, As and Cu in 1982 are substantially higher than those in This has resulted from the bias sampling of the gossanous zone on PARK 1 this year. Values for Pb and Zn are slightly elevated but not to the same extent as the others. Copper, zinc and arsenic all show a lognormal distribution of results. Gold, silver and lead show a flattening slope with increasing values. This is due to a positive skewness in the frequency curve, reflecting a large number of values above background. There are no generalized correlations that can be drawn between the various elements in the soils. In Trench 6 a copper, lead and zinc high occurs, whereas in Trench 8 high copper is associated with high gold values. Trench 5 has the highest values of Au, As and Ag occurring together. The strong Au-As correlation which occurs on Cominco's BILL claims 3 km to the south, is not so evident here. Analysis of rocks in the trenches reveals on average, lower, values than the soils. Some degree of enhancement of all elements has occurred in the soils of this area. Table 2 below summarizes the results of rock geochemistry and assays, and compares them to the soil geochemistry results. The enhancement from rocks to soil is evident in the soil/rock factor.

16 Soils Rock Geochemistry Rock Assay ~oil/~ock Factor. AU PP~ oz/ton ~g PPm oz/ton AS 1 cu 1 ~b PPm % Table 2: Comparison of Soil and Rock Results 25 8.O1 3.1 PPm PPm % I ~n ' PPm % O1 1.3 TRENCHING Eleven trenches were blasted and hand mucked in an attempt to expose fresh bedrock. The trenches were placed across and uphill of auriferous soil samples that had been collected in the previous year. Sampling technique has been previously discussed under geochemistry procedure. Depth of soil in this gossanous zone ranges from 50 cm to greater than 200 cm. Drawing Nos. AR.82-5 & 6 show trench locations and geochemical and assay results from each trench. Trench lengths vary from 8 to 14 metres with a width averaging 50 cm. CONCLUSIONS AND RECOMMENDATIONS A 200 x 200 metre gossanous zone on the west central portion of PARK 1 has been confirmed as a Au-Ag-Cu anomalous zone. Trenching across this zone has exposed bedrock in various locations throughout the gossan. A correlation exists between a silicified area of rock and a zone of high Au and Ag values both trending north-south down the hill. An area of hematite/ magnetite cemented quartz breccia with underlying massive magnetite exists to the west of the silicified zone. The extent of this magnetite is unknown at the present time. The source of the gold-silver-copper anomaly in soils has not been found by trenching, although it has been isolated to a, zone of silicified rock. A large degree of enhancement in soils of various elements has occurred. It is recommended that a geophysical survey consisting of both magnetometer and VLF-EM be conducted over the area to provide further information on subsurface geology.

17 l"lc COST STATEMENT 1. Wages (Aug. 2 - Oct. 15) 2 Jr. Field Assistants 5 1 Geologist (Field) 5 1 Geologist (office) 4 1 Blaster & Equipment 6 1 Blaster's Assistant 6 - Cost 2.. Camp Supplies (food, sundry) 3. Transportation Rotary Winq - ALC Airlift Corporation L, 6.2 $425/hr + $620 fuel. Fixed Wing - Central Mountain Air Services. Commercial Air Fare Vancouver-Smithers $ Smithers-Sturdee Valley: $ Blasting and Trenching Supplies (Powder, B-line, caps fuses) Bema Industries Invoice Nos. 7037, Analytical Services Min-En Laboratories 123 soil - $0.85 ea $ soil - Cu, Pb, Zn, Agl As, $12.70 ea 1, rock - $2.75 ea rock - Assays Cu, Pb, Zn, Ag, As, $47.50 ea 2, Expediting Bema Industries Invoice No. 2006

18 - 7. Radio Rental Spilsbury Communications (Invoice No ) 8. Freight (PWA, Loomis Courier) 9. Report Preparation TOTAL : $17,327.65

19 REFERENCES Drown, T. J.; Geological and Geochemical Report on the PARK 1-5 Claims, Liard Mining Division, British Columbia; Du Pont of Canada Exploration Limited Assessment Report, 12 pages; Lepeltier, C.; A Simplified Statistical Treatment of Geochemical Data by Graphical Representation; Economic Geology, Vol. 64, pp ; Thorstad, L.; Upper Paleozoic Volcanic and Volcaniclastic Rocks in Northwest Toodoggone Map area, British Columbia; Current Research, Part B; Geological Survey of Canada, Paper 80-lB, pp ; 1980.

20 QUALIFICATIONS I, Hugh J. Copland Jr., do hereby certify that: 1. I am a geologist residing at 5250 Ash Street, Vancouver, British Columbia and am employed on a temporary-summer basis by Du Pont of Canada Exploration Limited. 2. I am a graduate of the University of British Columbia with a B.Sc. onou ours) degree in Geology and McMaster University with a B.Eng. (~echanical). 3. I have practised my profession in geology for the past three years in British Columbia and the Yukon Territory. 4. In the summer of 1982, I participated in the field programme described in this report on behalf of Du Pont of Canada Exploration Limited. H. d. Copland 1982 October

21 APPENDIX A 'b. MIN-EN Laboratories Lrd. Spcrialisfs in Minerat Environments Comer 15th Street and Bewicke 705 WEST 15th STREET NORTH VANCOUVER, B.C. CANADA ANALYTICAL PROCEDURE REPORTS FOR ASSESSMENT WORK. PROCEDURES FOR Mo, Cu, Cd. Pb, Mn. Ni, Ap., Zn, As, F Samples are processed by Min-En Laboratories Ltd., at 705 W. 15th st. North Vancouver Laboratory employing the following procedures. fl 0 After drying the samp1.e~ at 95 C soil and stream. sediment samples are sc-reened by 80 mesh sieve to obtain the minus 80 mesh fraction for analysis. The rock samples are crushed by a jaw crusher and pulverized by ceramic. plated pulverizer gram of the samples are digested for 6 hours with HN03 and HC1o4 mixture. After cooling samples are diluted to standard. ' volume. The solutions are analyzed by Atomic Absorption Spectrophotometers. - copper, Lead, Zinc, Silver, Cadmium, Cobalt, Nickel and Manganese are analysed using the CH2H2-Air flame combination but the Molybdenum determination is carried out by.^ H -N 0 gas mixture directly or in directly (dependrng on the sensitivity and detection l i m i t required) on these sample solutions. or Arsenic analysis a suitable aliquote is taken from the above 1 gram sample' solution and the test,is carried out by Gutzit method using -Ag CS N 2 (C H ) as a reagent. The detection l i m i t obtained is. ppm. * I 2 Fluorine analysis is carried out on a 200 milligfam sample. After fusion and suitable dilutions the fluoride ion concentration in rocks or soil :samples are measured quantitatively by. using fluorine specific. ion electrode. Detection l i m i t of this test is 10 pprn F.

22 WQNE APPENDIX A MIN-EN~abbrator-ies Ltd Sprciofisfs in Mineral Environmcn~r Corner 75th Street and Bewicke 705 WEST '15th STREET NORTH VANCOUVER, B.C. CANADA ANALYTICAL PROCEDURE REFORTS FOR ASSESSNENT WORK.' PROCEDURE FOR GOLD GEOCHEMICAL ANALYSIS. Geochemical samples for Gold processed by Min-En Laborstories Ltd., at 705 W. 15th St., North Vancouver ' ~aborniory employing the following procedures. 0 After d.rying the samples pt 95 C soil and stream 4 sediment samples are screened by 80 mesh sieve to I obtain the minus 80 mesh fraction for analysis. he rock samples are crushed and pulverized by ceramic plated pulverizer;' - I.. A suitable sample weight 5.0 or 10.0 gra;ps are pretrea-ted with HNO and HC10 mixture. 3 4 ~ f t e r pretreatments the samples sre digested with Aqua Regia solution, and after digestion the samples. are taken up with 25% HC1 to suitable volume. At this stage of the procedure copper, silver and zinc can be analysed from suitable aliquote by Atomic ~bsorpt-on Sp~c~r~~hotbmetric procedure. Further oxidation and treatment of at least 757. of.. - the original sample solutions are made suitable for extraction of gold with Met.hy1 Iso-Butyl ~etone. I i ~i..th -a set of suitable standard solution gold is analysed by Atomic Absorption. instruments. he obtained detection l i m i t is 5 ppb.

23 APPENDIX B Calculation of Probability Graphs (According to Lepeltier, 1969) Procedure: 1. Geochemical data is assumed to follow a lognormal distribution. 2. Calculation of class interval ~og(interva1) = log R where R: Range of values n N: No points in curve This log interval is then recalculated as a ppb (or ppm) interval. 3. Cumulated frequencies are calculated from highest to lowest values and plotted on probability x log paper. A lognormal distribution should plot as a straight line. Two slopes represent a skewness in the population. 4. Analysis of graph: The following terms have been designated by Lepeltier. a. Background (b): For a perfect lognormal distribution, this is also the geometric mean and occurs at a 50% value. b. Deviation (s) : Standard deviation is defined as 68.3% of the population falling between (b-s) and (b+s) and is graphically represented by the 16% and 84% ordinates. c. Threshold (t): Is a function of the background and deviation log t = log b + 2s and is represented by the 2.5% ordinate. Following is a sample calculation for gold in soils: Total population: 123 Range (R) ppb Number of points desired on graph (n): 20 Log interval: log R = 0.18 n

24 APPENDIX B (continued) GOLD IN SOILS - PARK Log Interval Interval Frequency -% Cumulative ( P P ) ~ (%) TOTAL: 123 -

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