The Donnelly porphyry prospect of the GJ property is situated on the southwest portion of the Klastline Plateau. The GJ property is underlain by Stuhini Group rocks, intruded by the Groat Stock, and unconformably overlain by Lower Jurassic Hazelton volcanic rocks. Porphyry-style alteration and copper-gold mineralization occur within the stock and in the Stuhini Group rocks where disseminated, fracture, quartz vein and quartz stockwork controlled pyrite with variable chalcopyrite containing elevated gold values have been identified.
The Early Jurassic Groat stock intrudes Upper Triassic Stuhini Group fine-grained clastic and pelagic sedimentary rocks consisting of bedded sandstone, siliceous siltstone, chert and graphitic chert. Volcanic siltstone, sandstone and conglomerate overlie these siliceous sediments to the north. To the south are coarse andesite and basalt derived conglomerates. The country rocks are cut by several coarsely augite-phyric mafic sills which, in turn, are cut by Groat dikes.
The Groat stock is a faulted, northeast trending, coarse-grained porphyritic to fine-grained equigranular intrusion with granodiorite to quartz monzonite modal compositions. A Uranium-Lead age date of 205.1 plus/minus 8 Ma was determined by R.M. Friedman of the University of British Columbia (Fieldwork 1996, page 295).
The Donnelly and GJ zones are reported to be part of a very large intense sulphide system that occurs along the southern flank of the Groat stock. This sulphide system, as defined by geophysics, is at least four kilometres by one kilometre in extent and is open-ended. Within the sulphide system, almost continuous copper-gold mineralization has been traced for about 2.5 kilometres from the east end of the GJ zone to the west end of the Donnelly zone. The highest-grade interval of the 2005 program on the Donnelly is reported to be 46.95 metres grading 0.832 per cent copper and 1.317 grams per tonne gold within a thicker interval that graded 0.440 per cent copper and 0.647 gram per tonne gold over 130.95 metres (Canadian Gold Hunter Corp., Press Release, November 12, 2005).
Significant sulphide mineralization occurs in the intrusive and to a lesser degree in the country rock. This occurrence includes numerous small showings of disseminated, shear zone, and quartz vein stockwork mineralization. Pyrite and chalcopyrite are the most common sulphides with lesser amounts of sphalerite, bornite, covellite, galena, malachite and azurite. One 3.4-metre section of drill core contained 1.15 per cent copper and 2.85 grams per tonne gold (Assessment Report 8498).
The GJ/Kinaskan Lake property hosts three principal styles of mineralization: a) The porphyry copper-gold mineralization related to 205 MA aged quartz deficient intrusive rocks similar to the Groat stock. b) Disseminated pyrite ± chalcopyrite mineralization with copper-gold values associated with silicification related to 180 MA aged granite/felsite dikes. c) Dolomite quartz vein/fault-controlled pyrite-chalcopyrite-arsenopyrite ± sphalerite ± galena with gold and silver values. This occurs along north-south structures possibly related to mid-Jurassic rifting.
The most significant of the three styles of porphyry style mineralization is disseminated, fracture quartz vein and quartz stockwork controlled pyrite with variable chalcopyrite, rare bornite and trace molybdenite mineralization containing elevated gold values which have been identified in the North (104B 180), GJ (104B 034) and Donnelly zones (104B 086). Host rocks for copper-gold mineralization in all zones include intrusive and sedimentary rocks of which wackes and monzodiorite are the most significant. It is unclear, which unit, if any is the principal mineralizing phase, however mineralization is closely associated with steeply dipping fractured, brecciated intervals that are related to east-west to east northeast by west southwest striking faults.
Typically, the best chalcopyrite mineralization occurs where pyrite is weaker and IP chargeability responses are moderate, which generally occurs on the flanks of more intense chargeability anomalies. Secondary magnetite, generally associated with chalcopyrite, is found as disseminations, irregular clots, in veins with K-feldspar with or without chlorite and/or epidote and/or as fillings in single or sheeted fractures that are one to three millimetres thick and millimetres to 10 centimetres apart. Exceptions to this association (the Donnelly Deposit and portions of the North zone) appear to be where magnetite has been altered to hematite.
Host rocks to all styles of mineralization include: various intrusive phases; basalt tuffs, flows and dikes; and sedimentary rocks dominated by wackes. Where mineralization occurs in siltstones or cherts, it tends to be restricted to a few metres laterally from intrusive rocks or fault structures, and then only where it is near intrusive bodies. In wackes and basaltic rocks, the mineralization is largely disseminated with fracture and quartz-chalcopyrite-pyrite veins (with or without K-feldspar, magnetite, epidote and/or carbonate) constituting a smaller but significant portion. Where the mineralization occurs in intrusive rocks, it is largely confined to a fine- to medium-grained, equigranular monzodiorite phase, although mineralized monzonites, crowded feldspar porphyries and mafic leucocratic syenite phases have been noted.
Generally, the style of mineralization is similar to that of the volcanic and sedimentary rocks where disseminated pyrite and chalcopyrite dominate with fracture and quartz-chalcopyrite-pyrite veins (with or without K-feldspar and carbonate) constituting a slightly smaller percentage. However, in the 2005 drilling of the Donnelly Deposit, fault-bounded intervals of intensely altered intrusive, with up to 55 per cent quartz veining as sheeted veins to stockworks, were encountered in several drillholes at depth, as well as over the western-most two gridlines, covering the last 120 m of the deposit that had by then been drilled. In these zones, sulphides appear to be finer grained, occur equally in the intrusive and quartz veins and yield significantly higher copper-gold-silver grades. Multiple intrusive phases are apparent in and around the Donnelly Deposit and to date (2017) it was not possible to determine which intrusive unit, if any, is the principal phase associated with porphyry mineralization. The mineralization is, however, closely associated with strong fracturing and brecciation, which is very common throughout the Donnelly Deposit and which is associated with east-west to east-northeast striking faults.
Within the mineralized zone, regardless of whether rocks are intrusive or wackes, alteration consists of an early, selective pervasive potassic alteration overprinted by later, phyllic and propylitic (carbonate) alterations (Petrascience Consultants, 2004). Potassic alteration includes: selective replacement of rims of plagioclase by K-feldspar; K-feldspar–magnetite-chalcopyrite, with or without quartz, epidote, bornite veins and/or K-feldspar vein selvages; patchy K-feldspar replacement; replacement of mafic phenocrysts or phases by actinolite or secondary biotite; and secondary biotite envelopes developed along veins.
Phyllic and propylitic alteration is represented by quartz-sericite, with or without carbonate, chlorite, pyrite and/or epidote, which overprints the potassic alteration and yields the following textures: selective replacement of plagioclase cores by sericite with or without carbonate; veinlets of quartz-pyrite-chalcopyrite with or without carbonate; patchy and disseminated carbonate alteration of plagioclase, biotite and hornblende; replacement of secondary biotite by chlorite, with or without carbonate, epidote and/or rutile; and magnetite, chalcopyrite and pyrite that is variably rimmed and replaced by hematite.
Of the many porphyry copper-gold prospects located on the GJ claims block, the most advanced occur in an area measuring 3.5 kilometres east-west and north-south where disseminated, fracture, quartz vein and quartz stockwork-controlled pyrite with variable chalcopyrite, rare bornite and trace molybdenite mineralization containing elevated gold values occurs. This area contains the Donnelly Deposit, the North Donnelly deposit and the GJ and North zones.
WORK HISTORY
The first recorded exploration work carried out in the project area dates back to 1964, when Conwest carried out a regional evaluation of the Klastline Plateau and identified a number of porphyry copper-gold and precious metal shear-vein targets on the plateau including the GJ (104G 034) and QC porphyry systems (104G 033) and the Horn (SF) silver prospect (104G 035, 176,177). After staking claims over each prospect, Conwest carried out follow-up exploration programs. At GJ this included mapping and prospecting outcrop exposures along Groat Creek and carrying out limited silt and soil geochemical surveys near mineralized outcrops in 1964. In 1965 1.52 kilometres of I.P. and 1.83 kilometres of ground magnetometer surveys on the GJ showing were completed
In 1970, Amoco optioned the GJ project from Conwest and carried out 32 kilometres of I.P. and ground magnetic surveying along with geological mapping and soil sampling in the area of the main showing, before drilling five BQ diamond drill holes totalling 1529.8 metres, from one set-up on the main showing in Groat Creek. In 1971, Amoco constructed a rough access road from the south-west end of Kinaskan Lake up to the south end of the Klastline Plateau, and then northward to the GJ showing and the headwaters of Groat Creek. They carried out further geological mapping and drilled an additional 2479.1 metres of BQ core in 14 holes, nine in the GJ zone and five in the North Zone.
In October 1975, the Amoco claims were allowed to lapse and the 12-unit GJ claim was staked over the GJ showing and target by United Mineral Services Ltd. (UMS) A few days later Texasgulf staked the Goat-80 group claims to the west, north and northeast effectively covering what are now known as the Donnelly and North Zones.
In 1976, Great Plains Development Corp. (parent company - Norcen Energy Resources Ltd.) optioned the GJ property from UMS and carried out geological mapping, geochemical surveys, 22 metres of trenching along with constructing a 15.5 kilometres picket-line grid for a ground magnetic survey. During the same year, Texasgulf constructed 10.6 kilometres of picket-line grid over the Donnelly showing and target, completed I.P. and ground magnetic surveys over the grid, and did geological mapping and 51 metres of trenching.
In 1977, Great Plains carried out an I.P. survey over the 15.5 km GJ grid and geochemical sampling, and then dropped their option. Texasgulf continued exploration of the Donnelly target by extending the picket-line grid a further 13.1 kilometres, carrying out 18.5 kilometres of I.P. surveys, collecting 75 bedrock surface samples using a hand-held, gas powered Pionjaar drill. They then tested the Donnelly target with ten BQ diamond drill holes totalling 1523.9 metres. No further work was carried out on the Donnelly zone until 1980 when Texasgulf returned to the property and drilled an additional 1115.0 metres of BQ core in five holes, including four new holes and the deepening of previous hole TG-77-04. Texasgulf (which became Kidd Creek Mines Ltd. and was later acquired by Falconbridge Limited) carried out no additional exploration work and allowed the claims to lapse in 2000. In 1979, Dimac Resources Corp. purchased the GJ claims from United Mineral Services and then optioned them to Canorex Minerals Ltd. in 1981, who diamond drilled seven NQ holes totalling 1779.4 metres in the GJ Zone. Following Dimac declaring bankruptcy, Curator Resources Ltd. (later International Curator Resources) emerged as the sole owner of the GJ property in 1983. In 1989, Ascot Resources Ltd. optioned many claims covering the eastern half of the Klastline Plateau plus the GJ property from Curator. Field work in 1989 included 73 silts from drainages around the GJ target, 62 rock chip samples and 389 bedrock surface rock chip samples collected using a gas powered “wacker” drill. The following summer Ascot took 274 soils from contour lines along the plateau edge, conducted 20.7 kilometres of I.P. and ground magnetics on flagged grid lines and then drilled 1656 metres of BTW (1.654 inch diameter) sized core in nine holes before dropping the option.
In 2000, Curator carried out a very small program that involved taking 18 rock and 61 soil samples from newly staked ground covering the Donnelly and North zone targets when Falconbridge allowed the Texasgulf claims to lapse. This was followed in 2002 with the first of a multi-year, systematic evaluation of the copper-gold porphyry mineralization related to the Groat Stock. This work involved constructing a picket-line grid and carrying out 17.85 kilometres of I.P. and ground magnetic surveys over the Donnelly Zone target.
In 2003, in merging with Royal County, Curator acquired claims covering most of the remaining portions of Klastline Plateau including those immediately east and north of the North and GJ zones. Exploration on its Kinaskan (GJ) property, which includes the GJ, Goat (Donnelly) (104G 086) and North (new) showings comprised grid-controlled geochemical and geophysical surveys that helped develop drill targets, and a 1300 line-kilometre airborne high-sensitivity magnetic survey to search for new zones. In 2003, overburden drilling through a widespread till blanket outlined a copper-gold anomaly that extends the Donnelly zone 700 metres beyond previous drilling. In December 2003, Curator underwent a corporate re-organization and changed its name to Canadian Gold Hunter Corp.
In 2004, Canadian Gold Hunter Corp. conducted a 20-hole drilling program (4267 metres) on the Kinaskan (GJ) property to explore the poorly exposed Groat monzonite stock for a porphyry copper-gold deposit. A series of 200-meter step out holes in the Donnelly zone significantly enlarged the known extent of mineralization to an area 1100 meters long by 100 to 300 meters wide. The zone remains open along trend to the east and in width to the north.
In 2005, CGH accelerated the program on the property, concentrating largely on diamond drilling. An additional 11.3-line kilometre of I.P. and 34.9-line kilometre of ground magnetometer surveying expanded and filled in previous coverage. Soil sampling surveys were expanded. Thirteen hand trenches totaling 784 linear metres were excavated and sampled. Selected intervals of core from the Amoco, Canorex and Texasgulf programs were re-sampled for comparative assays. A total of 11,730 metres of diamond drilling in 37 holes was completed, mostly in the Donnelly Zone.
In 2005 eight holes totalling 2,336 metres were drilled in 2005 on the GJ zone. In addition, continuous chip samples from hand-dug trenches were taken over the original GJ showing in Groat Creek. Eight holes were drilled on the GJ and 13 on the North zone. It was not indicated how many of the remainder were drilled on the Donnelly.
Canadian Gold Hunter Corp., calculated an inferred resource for the Donnelly (Goat) occurrence in 2005 (Technical Report on the Donnell-GJ-North Copper-Gold Porphyry Zones, Canadian Gold Hunter Corp. May 15, 2005 (available on Canadian Gold Hunter website - www.canadiangoldhunter.com). The geological model was based on 5,256 metres of diamond drilling in 23 core holes with some 1,500 assays. Thirteen of the core holes were drilled by Texasgulf Canada Ltd. in 1977 and 1980. The other ten holes were drilled by Canadian Gold Hunter in 2004. A table at various cut-off levels follows:
___________________________________________________________Resource Cut-off Million Copper Gold Silver Category (% Cu) tonnes (%) (g/t) (g/t) Inferred 0.05 124.92 0.280 0.284 1.6 Inferred 0.10 105.10 0.320 0.323 1.8 Inferred 0.15 91.24 0.348 0.350 1.9 Inferred 0.20 71.22 0.397 0.398 2.2 Inferred 0.25 54.05 0.448 0.457 2.5 Inferred 0.30 41.47 0.501 0.521 2.8 Inferred 0.35 30.28 0.568 0.597 2.8 Inferred 0.40 24.46 0.614 0.665 2.8 ______________________________________________________________ |
In 2006, CGH continued its exploration of the Donnelly Zone while initiating drill testing of untested anomalies in the Donnelly North, YT, Saddle and North Zones. Work carried out included 32.1-line kilometres of deep penetrating IP and 53.8 line kilometres of ground magnetometer geophysical surveys; further geological mapping and prospecting; and diamond drilling 18,133.16 meters of NQ2 sized core in 62 holes (Assessment Report 29989). New resource estimates were calculated, using a 0.20 per cent copper cut-off, of 116.93 million tonnes indicated resources grading 0.361 per cent copper, 0.398 gram per tonne gold, 2.2 grams per tonne silver and 9.87 inferred resources grading 0.336 per cent copper, 0.365 gram per tonne gold, 1.8 grams per tonne silver (2007 Annual Information Form; www.canadiangoldhunter.com).
In 2007, CGH focused its exploration work on in-fill drilling of the Donnelly and North Donnelly Zones. In the Donnelly Zone a total of 4319 metres in 21 holes is reported. An updated resource for the Donelly zone was reported with an indicated resource of 116.93 million tonnes grading 0.361 per cent copper, 0.398 gram per tonne gold and 2.2 grams per tonne silver with and inferred resource of 9.87 million tonnes grading 0.336 per cent copper, 0.365 gram per tonne gold and 1.8 grams per tonne silver using a 0.20 per cent copper cut-off (Mehner, D.T., Giroux, G.H., Peatfield, G.R. (2007-04-30): Technical Report on the GJ Copper-Gold Porphyry Project).
In March of 2008 Canadian Gold Hunter Corp. released results from their 2007 drill program. Highlights included drill hole 07-197, which intersected 64.0 metres grading 0.49 per cent copper and 1.06 grams per tonne gold as well as drill hole 07-203, which intersected 72.5 metres grading 0.75 per cent copper and 1.03 grams per tonne gold (March 11, 2008 News Release; www.sedar.com).
In 2008, Canadian Gold Hunter press release announced an NI 43-101 compliant measured and indicated resource for the Donnelly and North Donnelly of the GJ property. This resource estimate is based on assay results from 169 diamond drill holes over a strike length of 1.6 kilometres. The resource, at cut-off of 0.20 per cent copper, is 153.3 million tonnes grading 0.321 per cent per cent copper and 0.369 gram per tonne gold containing 1.09 billion pounds of copper and 1.82 million ounces of gold. There is an additional inferred resource, at a cut-off of 0.20 per cent copper, of 23 million tonnes grading 0.26 per cent copper and 0.31 gram per tonne gold containing 132 million pounds of copper and 0.23 million ounce of gold (News Release, October 7, 2008).
The WILLOW claims were transferred to NGEx by a Bill of Sale registered on March 21, 2011, but it was Teck that explored the GJ property from 2010 through 2014. Their work included several limited diamond drilling campaigns and a considerable amount of ancillary studies, including: geological mapping in several areas to augment previous work; a major program of re-logging of historic drill core; various ground and airborne geophysical surveys; surface soil geochemical studies; an overview of archaeology pertinent to the property; collection of material for geometallurgical work; and other tasks. As part of their work, the existing camp facility was replaced by a much more permanent facility.
Work by Teck in 2010 was focused on further geological mapping concentrated around the Donnelly Zone. In addition, historical drill holes were re-logged. Geophysical surveys (ground magnetics and IP) and SWIR spectral studies also formed a large proportion of the work performed during 2010.
In 2011, the Teck operated program consisted of ground magnetics and an induced polarization (I.P.) survey, soil and rock sampling and 4,300 metres of drilling. The geophysics component of the 2011 field season comprised 76.6-line kilometres of I.P. surveys on nine lines, in addition to 50 kilometres of ground magnetic survey. A total of 10 diamond drill holes were drilled, taking note of lithology, mineralization and hydrothermal alteration. 1185 soil samples were also collected.
Further drilling on the Donnelly in 2011 by Teck included 61.85 metres grading 0.15 per cent copper and 0.21 gram per tonne gold; and another of 9.60 metres grading 0.15 per cent copper and 6.64 grams per tonne gold (Assessment Report 33085). Hole GJK-11-219 yielded a 141.21 metre interval grading 0.39 per cent copper and 0.54 gram per tonne gold (Assessment Report 33085). Six drill holes were drilled on the Donnelly, three on the Wolf, and one on the GJ. In 2012, Teck drilled 5 drill holes on the Wolf, 1 on the Seestor and 1 on the North zone. In 2013, Teck drilled 3 holes on the Donnelly.
In 2012, Teck drilled five holes, totalling 2613 metres, on the Wolf (MINFILE 104G 045) occurrence, three holes, totalling 2028.1 metres, on the Donnelly occurrence and three holes, totalling 1387 metres, on reconnaissance targets. Other work included ground and airborne geophysical surveys, soil and rock sampling and geological mapping.
In 2013, Teck completed 3 deep holes, totalling 2028.1 metres, on the Donnelly occurrence. A deep intercept in hole GJK-11-219 graded 0.39 per cent copper and 0.54 gram per tonne gold over 141.21 metres (Giroux, G.H., Peatfield, G.R., Cathro, M.S. (2016-02-24): Technical Report on the Donnelly-GJ Deposit Area, GJ Property).
In 2014, Teck completed a minor amount of geological work including the collection of samples for geometallurgical studies.
All 80 of the GJ property claims, held by Teck and its joint venture partner NGEx, were transferred to Skeena Resources Limited on November 03, 2015.
Most of the Skeena exploration efforts across the combined Spectrum-GJ property have been in the Spectrum Claims Block as result of the company’s acquisition of the GJ claims block occurring late November 2015. Despite this, prospecting, rock and soil sampling programs were carried out in addition to the drilling program in 2016 when bringing the total number of holes drilled into the deposit to 178 for a total of 49,240.37 metres (historical drilling plus the Company’s drilling).
In 2016, a combined measured plus indicated resource for the Main and North Donnelly (MINFILE 104G 189) zones was reported at 133.670 million tonnes grading 0.32 per cent copper and 0.36 gram per tonne gold with an inferred resource of 53.690 million tonnes grading 0.26 per cent copper and 0.33 gram per tonne gold using a 0.20 per cent copper cut-off (Giroux, G.H., Peatfield, G.R., Cathro, M.S. (2016-02-24): Technical Report on the Donnelly-GJ Deposit Area, GJ Property).
In 2017, Skeena Resources Limited filed a mineral resource update and a preliminary economic assessment for the project. Resources estimates for the GJ Donnelly deposit at 0.15 gram per tonne copper gold equivalent cut-off are as follows. In the Indicated resource category there are 215.2 million tonnes grading 0.31 gram per tonne gold, 1.9 grams per tonne silver and 0.26 per cent copper; and in the inferred category there are 28.3 million tonnes grading 0.31 gram per tonne gold, 1.8 grams per tonne silver and 0.14 per cent copper (Skeena Resources Ltd, Press Release April 20, 2017).
