Vancouver — In 1988, a junior company called Calpine Resources sparked an exploration frenzy in northern British Columbia by discovering the Eskay Creek gold-rich massive sulphide deposit. Today, using state-of-the-art computer modeling, another small company is hoping that lightening will strike twice in the Iskut-Sulphurets gold camp, just north of Stewart.
Heritage Explorations (HXL-V), formerly Heritage American, has launched a 4,000 metre drill program over its 473 sq. km land package around Barrick Gold’s (ABX-T) highly profitable mine. The junior is testing conceptual targets defined by Australian-based Geoinformatics Exploration, formerly Fractal Graphics. The Aussie company, which were the winners of the March 2001 Goldcorp Challenge, used all the available data from the region to develop a 3-D model to define drill targets. The effort lead to the identification of nine areas, which show similar affinities to the mineralization at Eskay Creek.
With two of the prospective zones lying on joint venture ground, Heritage inked a deal to earn the remaining 50% stake in does not already own in the Sib and Megan claims. Under the deal, Heritage must pay Uniterre Resources (UNT-V) $50,000 on signing and $300,000 before the end of October. Another $400,000 is due over the next two years in two equal installments. Uniterre retains a 2% net smelter royalty over the claims.
The 3.4 sq. km Sib claims are located adjacent and along strike from the Eskay Creek operation. Previous work between 1988 to 1991 defined a 1,680-metre strike length portion of the favorable Contact Mudstone horizon. This is the same horizon that hosts the Eskay Creek Mine mineralization
In 1990, 26-hole diamond drill holes, totaling 4,000 metres, tested selective geophysical and mineralized stratigraphic zones along the length of the Sib claims. One of the holes returned 14.3 metres grading 13.1 gram gold and 961.1 grams silver per tonne. Dubbed Lulu, the new discovery was followed-up by an additional 1,680 metres, with 4 holes intersecting massive barite with high gold and silver values and 25 holes cutting gold-silver bearing stockworks.
Some southeast of Sib, the junior also holds the Polo property, where in 1990 and 1991, rock chip, stream sediment and geochemical sampling and reconnaissance geological mapping were carried out. Grab samples returned up to 3.4 grams gold and 78.1 grams silver.
Another piece of ground held by the company, the Skookum claims are located 3-km north and northwest of the Eskay Creek mine. To date only limited first pass exploration has been carried out.
In August, Heritage picked up the bulk of its Eskay Creek ground by purchasing all the shares of privately owned Glenfred Holdings. The company held interests in 433 sq. km of ground in the area. Under the deal, the junior issued 7.4 million escrow shares to St Andrew Goldfields (SAS-T) (50%), Zebrex Holdings (37.5%) and Dolly Varden Resources (DLV-V) (12.5%). The shares will be released in amounts of 15% each at six-month interval starting Jan. 19, 2003. Insiders W. Frederick Christensen and Heritage’s Chief Executive officer, Glenn Laing were each granted 368,500 options in Heritage at an exercise price of 12.212 cents per share.
In the deal, Heritage picked up the prospective Bonsai and Treaty Creek properties. Located only 6-km from the Eskay Creek mine, the Bonsai property hosts a geochemically anomalous zone of gold-arsenic. Moving 20-km east of the mine, the Treaty Creek property hosts 10 mineralized zones.
The latest drill program will test the TV, Coul, AP, Noot, Unuk, Lance, Bonsai and Treaty conceptual targets identified from the modeling and confirmed by field evaluations.
The Eskay Creek region has a long history of exploration dating back to 1932 when T.S. Mackay first discovery mineralization there. Early work identified more than 30 distinct mineralized zones in upper Coulter and Eskay creeks along a line of gossanous bluffs that extends more than 7 km. The initial targets were located in the southern part of the area at the Mackay adit some 9 km southwest of the yet to be discovered 21 zone. In the northern part, some 3-km southwest of the 21 zone, underground development occurred at the Emma adit. Surface work included several thousand metres of diamond drilling, numerous trenches, pits and opencuts. In 1971, a 1.5-tonne sample of high-grade ore was extracted from trenches on the 22 zone, which lies 2-km southwest of the 21 zone. In 1979, these trenches were mined to produce 8.75 tonnes of hand-cobbed ore. In 1996, surface and underground exploration diamond drilling totalled 36,576 metres.
Murray Pezim-led Calpine hit the first real significant mineralization in 1989, when hole 109 cut 208 metres grading 27.2 grams gold and 30.2 grams silver. The rest, as they say, is history. Eskay Creek went into production in 1994 and the ore is so high grade (>3 oz. gold equivalent per tonne) that it is simply mined, crushed and shipped directly to smelters with no milling or concentrating. In 2001, the underground operation produced 320,784 oz of gold and 15.5 million oz of silver at a total cash cost of US$49 per oz of gold. For 2002, Barrick expects the mine to add 366,00 oz of gold and 16 million oz of silver to its global output.
Hosted in Middle Jurassic volcanic and sedimentary rocks, the bulk of the initial reserves were defined in the 21B zone, which forms a lens-shaped body up to 900-by-300-by-20 metres. The mineralization occurs as a stratabound sheet within carbonaceous mudstones of the contact unit and underlying rhyolite breccia, beneath mostly barren andesite flows. This is the horizon that Heritage aims to test on its ground.
In the north, sulphide layers also occur in the hangingwall andesite unit. Mineralization is marked by sphalerite, tetrahedrite and lead-sulfosalts with lesser galena and pyrite, and minor arsenopyrite. Stibnite and some times cinnabar locally overprint the mineralization. Based on mineral associations and continuity of grade, the 21 zone has been divided into two deposits: the 21A (formerly called the South zone) and the 21B (which includes the former Central and North zones). The deposits are separated by 140 metres of weak mineralization. Diamond drilling has traced the entire zone for 1.4 km along strike, 250 metres downdip over widths of 5-to-45 metres.
The 21C zone is centred about 450 metres due north of the 21A deposit. It is a discrete mineral zone 100 metres downdip from the 21B deposit and subparallel to it. The Pumphouse zone is located immediately northeast of Pumphouse Lake, east of the southern end of the 21B deposit. Mineralization displays both lateral and vertical zoning. Antimony, arsenic and mercury-rich mineral assemblages in the south change to zinc, lead and copper-rich assemblages in the north. Vertical zoning is expressed as a systematic increase in gold, silver and base metal content up-section. The 21 zone mineralization is unusual in that there is a close relationship between low-temperature epithermal gold-silver and volcanogenic massive sulphide deposit types. Epithermal mineralization characterized by gold, silver, arsenic, antimony and mercury mineral suites, forms massive and stratabound lodes as well as more usual crosscutting veins and disseminations. Massive sulphide mineralization show typical ore textures but atypical mineralogy and precious metal enrichment.
The exploration success did not stop with the start of production. In 1995, the NEX and Hangingwall zones were hit. The bulk of stratiform ore is contained in the 21B and NEX zones, which are both, hosted in marine mudstone overlying rhyolite. The NEX zone lies north of the 21B lens, at the same stratigraphic horizon, and consists of mainly massive sphalerite, tetrahedrite, galena and lesser lead-sulfosalts, with late chalcopyrite stringers crosscutting the lens. The Hanging Wall zone is stratigraphically above the NEX zone, usually above the first basaltic sill, and is dominated by pyrite, sphalerite, galena and chalcopyrite.
The underlying rhyolite hosts vein systems that are interpreted as feeders for the stratiform mineralization. The stockwork vein and disseminated sulfides are most noticeable in the 109, 21C and Pumphouse zones. The entire host sequence comprises a succession of andesite, marine sedimentary rocks, intermediate to felsic volcaniclastic rocks, rhyolite, mudstone which hosts stratiform mineralization, and basaltic sills and flows which are intercalated with turbiditic mudstones. The sequence is capped by a thick accumulation of clastic rocks, which fill the Bowser Basin. The mine stratigraphy is folded into a north-northeast trending upright open fold, plunging gently to the north. Stratiform ore lenses occur on the western limb of the fold, near the fold closure, and generally dip 30 to 45 degrees to the west. Northwest trending faults, as well as north to northeast axial planar faults, cut the sequence. Metamorphic grade in the area is lower greenschist facies.
Heritage is concentrating on the favourable contact unit, which is dominantly comprised of sphalerite, tetrahedrite and possibly boulangerite with varying amounts of galena and chalcopyrite. Alteration minerals are again chlorite, muscovite, quartz and calcite. Mineralized textures vary from crudely banded massive sulphides to thick and thin sulphide bands intercalated with mudstone.
The junior is currently in the midst of a $1.5 million financing aimed for further work on the project. The private placement includes 1 million flow through units and 1 million regular units both priced a 75 each. A regular unit holds 1 share and 1 warrant, which is exercisable at $1 for 18-months.
St. Andrews and Zebrex each hold a 28.4% stake in Heritage. The company currently has 4.4 million shares outstanding, 6.95 million fully diluted.
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