Engineer Gold Mine
Exploration & Development Strategy
Blind Creek Resources Ltd. acquired 100% interest in the Engineer Mine property from BCGold Corp. (now Pan Andean Minerals Ltd.) in February, 2017. The historic high-grade gold-silver mine is situated 32 km west of Atlin, B.C. Over the past 10 years BCGold spent >$4.7M at Engineer Mine with a focus on property consolidation, exploration for additional high-grade and bulk tonnage mineralization, test mining, bulk sampling, test milling and mineral resource development. Since acquiring Engineer Mine, Blind Creek has more than tripled the property size (currently 11,556 hectares) through recent staking. Blind Creek is now positioning to continue exploration and resource and mine development at Engineer Mine.
Location & Access
Located 32 km west of Atlin, B.C., 140 km south of Whitehorse, Yukon, situated on east shore of south arm of Tagish Lake and easily accessed year-round by boat / barge / float plane (summer) or ice road / ski plane (winter).
Mine History (See below for more detailed mine history)
Property and Ownership
- Historic high-grade gold producer (peak production mid-1920s, ceased operation early 1930s)
- >18,000 oz gold and 9,000 oz silver officially produced at realized grades exceeding 39 g/t Au and 20 g/t Ag
- Narrow, high-grade epithermal quartz-carbonate veins (Boulder, Double Decker, Engineer) mined on 6 of 8 mine levels
- The Engineer Mine property consists of six crown grants, five legacy mineral claims, and 41 Mineral Titles Online "MTO cell" claims that surround and overlap the crown grants. The total contiguous property package covers an area of approximately 11,556 hectares.
- Blind Creek has a 100% interest in property
- Fully permitted historic mine located on central core of patented crown grants.
- Pan Andean holds a 1.0% net smelter return royalty ("Pan Andean's Royalty") on the Engineer Mine property, the Gold Hill property, and the Company's Blind Creek property that borders the west and south sides of the Engineer Mine and Gold Hill properties. Guardsmen Resources Inc. retains a 2.5% net smelter return royalty ("Guardsmen'sRoyalty") on the Gold Hill property. Blind Creek has rights to buy back all of Pan Andean's Royalty and to buy back up to 2% of Guardsmen's Royalty.
High-Grade Gold Mineralization & Exploration Potential
- Inferred Mineral Resource of 41,000 t grading 19.0 g/t gold for 25,000 oz contained gold, or 14,000 t grading 52.5 g/t gold for 23,600 oz contained gold, calculated by Snowden Mining Industry Consultants Ltd. and described within their 2011 NI 43-C 101 compliant Technical Report
Bulk-Tonnage Gold Exploration Potential
- historic production was from, high-grade, bonanza-style, low-sulphidation epithermal quartz-carbonate +/- roscoelite +/-Au +/- Ag veins (historic gold target) occur adjacent to a second-order semi-brittle and brittle shear zone splay of the crustal-scale Llewellyn fault
- gold mineralization occurs primarily as electrum, in association with roscoelite, in discrete, vertical, high-grade ore shoots
- >25 known veins on the core property
- only 4 veins (Engineer, Double Decker, Boulder, Shaft) have seen limited production / exploration
- essentially unexplored below 200 m from surface; all veins remain open at depth
Near-Term Production Potential
- property overlays >8 km of highly prospective 2nd order shear structures known to hold significant low-grade gold-silver mineralization.
- Shear Zone "A" defined over 400 m strike length with near-surface drill intercepts up to 0.45 g/t Au over 34 m (2008)
- Shear Zone "A" remains open along strike and at depth
- +50 m thick gold-bearing hydrothermal breccia zone traced within Shear Zone "A"
- Undrilled and open-ended >1.0 km long gold-silver-arsenic soil anomaly 0.5km East of mine spatially related to Shear A, broad resistivity and magnetic high anomalies.
- Shear Zone "B" has been defined for 2.5 km northward from, the mine trending towards the Happy Sullivan high-grade gold epithermal prospect
- potential for low-grade (2 -- 7 g/t Au) 0.5 -- 2M oz. gold deposit in mine area of Shear Zone "A":
- predicated on historical reference to chip sample series averaging 5.1 g/t Au taken from 45 m crosscut on mine's deepest level (8 Level)
- sampling conducted in early 1930s, not followed up
- potential quantity conceptual in nature
- insufficient exploration completed to define a mineral resource on Shear Zone "A"
- uncertain that further exploration will result in target being delineated as a mineral resource
Mine History and Previous Exploration & Development Programs (1899 -- 2007)
- permitted 30 tpd gravity separation mill on the property
- access and production drifts in place for 6 veins
- excellent potential for resource development and near-term small scale production from existing underground headings on Boulder, Governor, Jersey Lilly, Shaft, Double Decker and Engineer Veins
- excellent potential for additional bonanza-grade vein mineralization at depth and laterally within the current workings
- Company permitted to dewater 3 lowest mine levels at any time
- minimal development required for near-term, sustainable small scale gold production (30tpd)
- sustainable production could be ramped up to 100-200 tpd within 2-3 years with nominal capital for exploration, mine and mill upgrades and additional permits
The history of the Engineer Mine property dates back to 1899 when an engineer from the Yukon & White Pass Railway discovered visible gold in quartz veins on the shore of Tagish Lake below Engineer Mountain. He returned with associates and they staked the Engineer Group of claims. After some development work, the claims were allowed to lapse in 1906, but were re-staked and sold in 1907 to Captain James Alexander and partners.
In 1912, Captain Alexander took control and systematically explored the property. He developed the upper levels of the underground workings and built a stamp mill at what is now known as the 1-Level Entrance. He processed over 2,000 ounces of gold over several seasons. In 1918, Captain Alexander died in the sinking of the Steamship Princess Sophia. He died along with many others, including two men involved in a deal that had just been made for the sale of the Engineer Mine to the Mining Corporation of Canada. After his death, several claimants appeared with interests in the Property, and many years of litigation followed.
The Property was taken over in 1923 by a New York group and mining began in 1924 for Engineer Gold Mines Limited. Developments at this time were the most significant that the property had yet seen, including the development of the town site, the installation of a power plant on the Wann River with transmission lines to Engineer, and the concentrator and mill on the lakeshore near the 5-Level portal. Over 140 people were employed at the site at this time and development of the underground tunnels down to the 8-Level occurred at this time. The presence of visible gold was the primary method of identifying and following ore shoots in the veins. Reserves were exhausted by 1927, but development continued with drifting and limited mining on the 6, 7 and 8 levels until 1933. Underground workings consist of about 5,500 metres of drifts, shafts, raises and stopes on 8 levels.
A total of 562 kilograms gold (Au)
(18,000 ounces) and 278 kilograms silver (Ag)
(9,000 ounces) was reportedly produced from 14,263 tonnes of ore at Engineer Mine in the period between 1913 and 1952. This equates to total realized gold and silver production grades of 39 g/t Au
(1.2 oz/ton) and 20 g/t Ag
(0.6 oz/ton) respectively.
The property changed hands several times in the intervening years. Reginald Brook, an associate of Captain Alexander, stayed on as caretaker of the property and selectively hand-mined parts of the mine. In 1944 a group of miners leased the property and high-graded the veins on the underground workings until 1952.
Several exploration companies worked on the property from the 1960's to 1980's, to varying degrees. These include: Tagish Gold Mines in the early 1960's, Nu-Energy Resources Limited in 1975 who sampled the hydrothermal breccia zone along Shear Zone A on the 5-Level, and Nu- Lady Gold Mines Ltd. in 1979. In 1987, Total Erickson Resources Limited conducted a comprehensive exploration program that included an aeromagnetic survey, detailed geological mapping and sampling and drilling.
Gentry Resources Ltd. optioned the property from Total Erickson in 1989, and acquired title to the property in 1990 with Winslow Gold Corp. Ampex Mining acquired an interest in the property from Winslow in 1993, and through further transactions the property interest was passed to Old Engineer Mining Corp. who underwent a name change to Engineer Mining Corp in 1997.
During 1991 to 1992, the portal and most of 5 Level was rehabilitated by Ampex and some original documents were acquired from Jim Brook whose grandfather Reginald had worked on the property from 1899 to the 1930's. Blasting and sampling on the No. 2, No. 3, and Double Decker veins was unsuccessful in locating new gold shoots. On the Engineer vein, impressive samples of gold in roscoelite were collected on small remnants of an ore shoot found in pillars between surface and 2 Level, and along the 5 Level (bonanza shoot). Access to the 3 and 4 Levels was not attempted. In 1993 the northeast part of the mine was re- habilitated. At the north end of the Boulder vein (524 raise), approximately 150 tons of material averaged approximately 31 g/t Au and a smaller sample at the south end (523 raise) averaged 26 g/t Au. A boating accident at the end of the summer resulted in the loss of the daily records, mining journal and rock samples.
During the 1994 season, EMC secured permitting for a 30 ton per day pilot mill and a 10,000 ton bulk sample. The mill, a 150 kW generator, an enlarged camp, a dump truck, a D7 Cat and a 931 Cat loader were barged to site and assembled. A 50 ton sample from the 505-1 raise (Engineer vein) was processed, but problems in the mill circuit prevented an accurate assessment of grade. A 30 ton sample from the 524-2 raise (Boulder vein) was more successfully processed and yielded a grade of approximately 27 28.6 g/t Au. In 1995 track mining equipment was purchased and 600 m of track installed. Bulk sampling continued and a total of 945 tons of material from both surface and underground was processed with variable results.
Previous Exploration & Development Programs - BCGold Corp. (2007 -- 2016)
- 2007 Exploration:
- $500k program entailing surface and underground mapping and sampling on 5 Level, 3D mine modeling (VULCANTM), exploration targeting and resource estimation
- 2008 Exploration:
- 1,850 m diamond drill program defined Shear Zone "A" structure over 400 m strike length with near-surface drill intercepts up to 0.45 g/t Au over 34 m
- 600 m trench excavation completed on Boulder, Shaft, Double Decker and Shear "B" zones, all of which were either exposed or partially developed 120 m vertically below on 5 Level in the 1920s; exposed veins geologically mapped and channel sampled
- 2010 Exploration:
- 1,100 m underground drilling confirmed high-grade depth extensions to Engineer (129.0 g/t Au and 121.63 g/t Ag over 1.00 metre) and Double Decker (22.32 g/t Au and 17.59 g/t Ag over 0.96 metres) Veins
- Snowden commissioned to complete NI 43-101 compliant Technical Report and Mineral Resource estimate
- 2011 Exploration, Bulk Sampling & Test Milling:
- $1.1M program completed based on Snowden Mining Industry Consultants Ltd.'s exploration and development recommendations to increase the mineral resource and take property to small scale production in near term (see BCGold May 25, 2011 news release)
- 30 tpd pilot mill circuit refurbished and optimized
- 6 bulk samples (400 tonnes) mined from Engineer and Double Decker veins (see BCGold October 6, 2011 news release)
- 246 tonne composite sample milled, returning average mining head grade of 16.9 g/t gold
- wire gold in roscoelite and/or fine gold in quartz observed in all samples
- 969.2 kg dry concentrates (Table, Sluice and High-Grade Gold Stream) recovered from composite sample returned weighted average grade of 2139.1 g/t gold, containing estimated 68.3 oz gold
- preliminary test milling averaged 51.3 % gold recovery from the on-site gravity separation mill
- 60% of composite sample mined outside of current Inferred Mineral Resource (see BCGold February 27, 2012 news release)
- new exploration target defined on high-grade "505-3" shoot discovery, within Engineer vein and outside current Inferred Mineral Resource (see BCGold February 29, 2012 news release)
- 600 line km SkyTEM deep penetrating Time-Domain Electromagnetic / Magnetic airborne survey conducted over Engineer Mine and Gold Hill properties; numerous exploration targets defined for follow-up
- 2012 Exploration & Development:
- Completed $550,000 exploration and mine-dewatering program on Engineer Mine and Gold Hill properties
- geologically mapped, prospected and conducted MMI soil surveys over Shear Zone "A" and "B" bulk tonnage gold exploration targets
- MMI surveys detected 3 Shear Zone style, bulk-tonnage gold drill targets on Engineer and Gold Hill properties
- dewatered 6 and 7 Level of underground mine workings to access down-plunge extension of high-grade 505-3 and 505-5 Shoots on Engineer Vein
- installed air and water services to 6 and 7 Level, completed geological mapping and panel sampling
- underground panel sampling confirmed Engineer Vein and high grade gold shoots persist at least to 7 Level
- 2012 grab samples on 6 and 7 Level up to 12,720 g/t Au and 3,180 g/t Au, respectively
- 2012 Metallurgical Work & Concentrate Sales:
- approximately 0.8 dry metric tones gold-rich gravity concentrate produced during 2011 bulk sampling sold to Auramet Trading, LLC at US$1608/oz for $107,000 (see BCGold June 26, 2012 news release)
- Gekko Systems of Ballarat, Australia conducting on-going metallurgical studies consisting of bench-scale gravity and leach amenability tests on mill feed and table concentrate from 2011 program
- In 2014 BCGold conducted a limited soil geochemical and MMI soil survey south of the immediate mine area.
- In 2016 BCGold conducted a follow-up MMI soil sampling survey south of the mine, defining a number of Au-Ag-As-Sb geochemical anomalies.
- historic development includes >5,500 m of drifts, shafts, raises and stopes; 8 mine levels developed, main portal on 5 Level (with rail)
- narrow veins and headings, ground in excellent condition
- lowest 3 mine levels flooded (Company permitted to dewater at any time)
Geology of the Tagish Lake Region
- all-season 20 man trailer camp on property
- fully functional, permitted 30 tpd gravity separation mill on site
- permanent, industrial dock to be utilized for loading and offloading float planes and barges
- main underground access provided by tracked portal on 5 Level
- power, air, water available to most areas of 5 Level and 6 and 7 Levels
- compressors, generators, electric loci and four 1-ton ore cars, as well as a mucking machine on 5 Level (all Company-owned)
- small bulldozer and gravel truck on property
- vestiges of historic hydro-electric power line from power plant on the Wann River (5 km south) evident
Two crustal scale sub-parallel, northwest trending faults transect the Engineer Mine Property area, the Nahlin Fault Zone in the eastern property area and the Llewellyn Fault Zone through the Wann River area. The faults are grossly coincident with terrane boundaries. A belt of anomalously high regional gold-arsenic and antimony geochemistry extends the length of the Tagish Lake area, coextensive with the Llewellyn fault.
The Engineer Mine and Wann River claims are underlain by Carboniferous to Triassic oceanic rocks of the northern Cache Creek Terrane to the east of the Nahlin Fault Zone, Devonian to Permian metamorphic rocks of the Yukon-Tanana Terrane to the west of the Llewellyn Fault Zone and Triassic to Jurassic sedimentary strata of the Whitehorse Trough between the faults. The above lithologies are cut by Late Cretaceous to Tertiary intrusions and intruded by Eocene plugs and dykes and overlain by associated volcanic rocks and basal coarse clastic sedimentary rocks of the Sloko Group.
The Tagish Lake region hosts significant low-sulphidation epithermal gold-silver mineralization (Engineer Mine area), polymetallic veins (Ben-My-Chree), gold quartz vein (potential in Graham Creek area), copper (Whitehorse Copper) and gold skarn (TP in northern Tagish region) deposits, and possible Kuroko-style volcanogenic massive sulphide (Tulsequah Chief) deposits within Yukon-Tanana Terrane and copper-molybdenum-gold porphyry and gold-silver rich Eskay type shallow subaqueous hot spring deposits within the Whitehorse Trough.
Geology and Mineralization at Engineer Mine
Native gold is the principle metallic mineral at Engineer Mine. The Engineer Mine is noted for museum class gold and electrum specimens and is a type locality for the mineral allemontite (stibarsen and native arsenic). Gold grades at the Engineer Mine are sporadic, ranging from trace to >50 grams per tonne gold.
Quartz veining and gold mineralization occurs in two modes at the Engineer Mine property, in brittle deformation and hydrothermal breccia zones along Shear Zone "A" and in bonanza shoots within low-sulphidation quartz-carbonate veins peripheral to the Shear Zone "A" deformation zone.
Shear Zone "A"
Shear Zone "A" is a northwest-trending 200 metre-wide shear zone with a protracted deformation history, related as a splay to the major terrane-bounding Llewellyn fault. Earliest semi-ductile deformation along Shear Zone "A" may be as old as Late Triassic. Shear Zone "A" was reactivated along its northern boundary in the Eocene. The reactivation coincides with the emplacement of a volcanic complex immediately to the southeast at Engineer Mountain; part of the Sloko Group. Hydrothermal fluids related to the Sloko Group volcanic complex were focused along Shear Zone "A" and other pre-existing fractures on the property, resulting in gold-bearing hydrothermal veins and breccias.
Brittle Deformation and Hydrothermal Breccia Zones
The first mode of gold mineralization at the Engineer Mine property, occurring in brittle deformation and hydrothermal breccias zones along the Shear Zone "A" deformation zone, represents a bulk tonnage gold target. This gold occurs in quartz-calcite-pyrite cemented hydrothermal breccias and quartz vein zones 50 metres along a strike length of more than 250 metres. The lateral and depth extents have not been tested. The breccia zone is focused along the north side of Shear Zone "A", in the Eocene reactivated domain. Several breccia types are recognized in core, including pyrite cemented polymict breccias, fine pale quartz-cemented breccias, dark siliceous breccias with varying clast content, and intrusive clast breccias. Overprinting, multi-stage quartz-pyrite veining relationships are also recorded in core. Gold values are highest in zones of fine quartz flooding, and high silver values are attributed to quartz-arsenopyrite-stibnite veins.
High-Grade Gold and Silver Veins
The second mode of mineralization at the Engineer Mine property is in high-grade gold and silver veins that occur outside of the Shear Zone "A" deformation zone. These quartz-calcite veins formed in pre-existing structures that were re-opened during the Eocene hydrothermal event and reactivation of Shear Zone "A". To the south of Shear Zone "A", the veins are both extensional and shear in character. They show a structural relationship to Shear Zone "A" movement. Historic production in the area was from the Engineer and Double Decker veins (view Summary Map) that extend south from the reactivated section of Shear Zone "A". These veins are less than 2 metres wide, strike northeast, and pinch and swell along strike but have good vertical continuity.
Other important gold veins that occur outside of the Shear Zone "A" deformation zone are the high-grade Shaft vein and the Boulder-Governor vein system; all are to the north of Shear Zone "A". The Shaft vein is vertical on surface but changes to moderately southwest-dipping at depth. It produces coarse free gold. A high-grade zone on the Shaft vein, 113 metres below surface on the 5 Level underground, has bands of arsenopyrite and stibnite up to 1 centimetre wide. The mineralogy is similar to the very high grade Engineer vein to the south. The nearby Bolder-Governor vein system produces free gold in quartz and carbonate concentrated in hydrothermal breccia zones up to 5 metres wide and 50 metres long at vein intersections. The veins strike northwest and southeast. Bonanza gold grades were mined in the 1990's at these vein intersections.
The host rock to all the veins and breccia zones on the Engineer Mine property is argillite and greywacke of the Laberge Group. Monzodiorite dykes related to the Sloko Group complex occur across the property, displaying varying degrees of quartz-carbonate-clay alteration. Some of the most altered dykes may be rhyolite dykes from the same intrusive event.
Wann River Exploration and Mineralization
Seven Minfile occurrences are documented on the southern Wann claims; the Kim (109.7 g/t Ag, 0.7 g/t Au and 4.0% Cu) and Douglas polymetallic vein showings in the southwestern property area, the Kirkland showing and Gleaner prospect covering epithermal veins near the Engineer Mine, the Graham Creek placer and upstream extent in the northern property area, and the Brown polymetallic vein showing and the copper-nickel-platinum-palladium Anyox-Rodeo prospect within the Wann River area.
Previous exploration by Blind Creek Resources Limited in the Wann River area was focused on a 160° trending, 800m long by 180m wide corridor with quartz vein mineralization occurring within Devonian to Triassic Boundary Range biotite-feldspar-quartz schist in the southwest, and a faulted panel of Upper Triassic Stuhini andesite and quartz eye porphyry in the northeast.
Mineralization at the Brown showing within the corridor consists of tetrahedrite/freibergite, chalcopyrite, malachite, azurite, molybdenite, pyrite, sphalerite and galena. A sample collected from the Brown adit in 2010, returning 8.6 g/t Au and 420 g/t Ag over 0.3m, confirmed previous results by the British Columbia Geological Survey from a chip sample (assaying 8.6 g/t Au and 315.38 g/t Ag) and verified the presence of significant gold-silver values on the Wann River portion of the Tagish Lake Project.
2010 Exploration at Wann River
Results from grab samples from the Wann River area include 263 g/t Au, 1350 g/t Ag, 2.75% Cu, 4.45% Pb and 1.36% Zn hosted by quartz from tailings in the Lum trenches, and 15.9 g/t Au, 440 g/t Ag, and 1.04% Pb from the Newfie, 17.2 g/t Au from the Trail, including 32.9 g/t Au, 1180 g/t Ag and 3.35% Cu and 3.79% Pb from float, and 126 g/t Ag from the River quartz vein showings.
A 2011 Technical Report on the Tagish Lake Project recommended a significant exploration program on the Wann River portion of the Tagish Lake Project. A program consisting of 2,000m of diamond drilling to evaluate the southeastern sector of the corridor, a ground magnetic geophysical survey to aid in geological mapping, and additional prospecting, mapping and sampling was recommended on Wann River with a budget of $950,000.