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File Created: 31-Aug-1989 by George Owsiacki (GO)
Last Edit:  24-Jul-2018 by George Owsiacki (GO)

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NMI
Name BLACKWATER, BLACKWATER-DAVIDSON, PEM, SILVER, GOLD, MT. DAVIDSON, BLACKWATER SOUTH, DAVIDSON, DAVE, KAOLINITE RIDGE Mining Division Omineca
BCGS Map 093F016
Status Developed Prospect NTS Map 093F02W
Latitude 053º 10' 22'' UTM 10 (NAD 83)
Longitude 124º 51' 29'' Northing 5893103
Easting 375810
Commodities Gold, Silver, Zinc, Lead, Copper Deposit Types H05 : Epithermal Au-Ag: low sulphidation
Tectonic Belt Intermontane Terrane Overlap Assemblage
Capsule Geology

The Blackwater property is located about 7 kilometres northeast of Mount Davidson, about 160 kilometres south of Vanderhoof.

Topographically, the Blackwater deposit forms an S-shape due to resistive silicification and inferred glacial scour within a cirque valley on the north side of Mt. Davidson. The Blackwater wedge occupies a roughly 5 kilometre square area and is juxtaposed against Ootsa Lake Group rocks across steeply dipping normal faults on the west and north, implying the Blackwater block is a high-standing remnant or horst in the region, preserving a Late Cretaceous volcanic edifice

In the Blackwater region, Hazelton Group consists of a lower unit of felsic tuffs and sediments, named the Entiako Formation and an upper unit of felsic to mafic volcanic flows and volcaniclastic and sedimentary rocks, termed the Naglico Formation. Hazelton Group rocks are overlain by post-accretion Upper Jurassic volcaniclastic, sedimentary and mafic to felsic volcanic rocks of the Bower Lake Group. The Hazelton and Bowser Lake groups in the area are collectively intruded by Late Cretaceous granitic to granodioritic plutons exposed within the Nechako uplift. Rocks of the Hazelton and Bowser Lake groups are overlain by Upper Cretaceous and Paleocene continental volcanic arc intermediate volcanic rocks and related sedimentary rocks of the Kasalka Group. Widespread Eocene volcanic arc related extensional felsic volcanic rocks and minor sedimentary rocks of the Eocene to Oligocene Ootsa Lake Group overlie the older rocks and are themselves overlain on higher ridges by basalt and andesite of the Eocene Endako Group

The Blackwater project area is underlain by intercalated volcanic and volcaniclastic felsic to intermediate lapilli and ash tuff, volcanic breccia and andesitic flows. These strata form a local wedge of laterally discontinuous strata. The Blackwater wedge is thought to dip generally northwest and is of limited aerial extent. On the west the Blackwater wedge is faulted against younger massive felsic volcanic rocks of the Ootsa Lake Group. The fault is a north trending, presumed steep dipping structure. A similar relationship exists on the north side where Blackwater host rocks are also juxtaposed next to Ootsa Lake Group strata across an east- northeast trending fault. Although displacement across the faults is not known, the relative age of rocks across the two faults implies that the Blackwater block is a horst or high standing remnant west and north of which the Ootsa Lake Group dropped to the west and north. East and south of the Blackwater block the relationship to the country rocks is unknown but presumed stratigraphic. Likely the Blackwater strata are underlain by Bowser Lake Group beds as at Capoose Lake.

The Blackwater wedge consists of a sequence of felsic to intermediate composition volcanic rocks. Individual mappable lithologies include felsic tuffs and lapilli tuffs, volcaniclasitic and epiclastic heterolithic breccias, and massive to layered andesites. Dark reddish-brown anhedral equant, garnet crystal fragments up to a centimetre in diameter are common as an accessory in the heterolithic breccia and locally make up 1 to 2 per cent of the rock.

Blackwater wedge rocks are pervasively hydrofractured and silicified. The amount of silica introduced through hydrofracturing and silicification may amount to 25 per cent or more of the total volume of volcanic rocks. Although intensely hydrofractured, the Blackwater wedge lacks clearly recognizable large scale faults or shear zones. Instead, extensive zones of broken rocks are seen in the mineralized zone. The zones grade laterally into unbroken rock and are generally not bounded by planar surfaces.

Mineralization is hosted within felsic to intermediate composition volcanic rocks of Late Cretaceous age (Kasalka Group) emplaced through and on Hazelton Group strata. The rocks are extensively hydrofractured and silicified and in association with pervasive stockwork and disseminated fine grained pyrite and other sulphide minerals distributed throughout. Gold is mainly associated with the sulphide minerals as gold grains between 5 and 50 microns across.

The Blackwater gold-silver deposit is interpreted as an intermediate sulfidation epithermal system. Mineralization is hosted by Late Cretaceous Kasalka Group rocks in a complex assemblage of andesite flows, lapilli tuffs and volcanic breccias; flow-banded and tuffaceous rhyodacites; heterolithic breccia containing altered fragments of other units; and intensely silicified hydrothermal breccias. Strata are discontinuous over short distances but are more discernible in the southeast corner of the deposit and are thought to dip generally northwest. Andesite host rock lies outside of the silicified zone and may represent the protolith for much of the orebody, particularly in chlorite-sericite altered portions. Alteration and mineralization is hosted in a large upright funnel-shaped fragmental zone that averages 350 metres thickness and tapers to 600 metres depth in a low-grade core. It is characterized by pervasive silica-muscovite-illite ± chlorite accompanied by disseminated and replacement pyrite-sphalerite-chalcopyrite-galena ± marcasite. Native gold and electrum as micron scale grains) are associated with sulphide and silicification, and silver with argentite occurring with galena. Local manganese (Mn)-rich spessartine garnet, an important indicator mineral, occurs with pyrrhotite-bearing potassic alteration in the western part of the deposit. The mineralized zone (above 0.2 gram per tonne gold) strikes east-west and dips shallowly north-northwest over an area measuring 1250 by 1000 metres. It is continuous across the central and southeastern parts of the deposit and extends to the north and northwest where a zone of higher grade silver lies along the outer portion of the 2012 drilling grid. Mineralization remains open at depth in the southwest and in the north and northwest of the deposit. Steep, north-plunging high-grade ore shoots are thought to be associated with subvertical structural intersections. Traces of arsenopyrite, tetrahedrite and boulangerite also occur.

Highest grades are localized along the margins of silicified breccia bodies. The silicified mass has moderate resistivity-chargeability and increasing chargeability marginal to silicification. The large fragmental zone of seriate subangular clasts (some glassy or devitrified shards) in a finer-grained matrix and pervasive silicification with minor quartz veinlets suggests a widespread metasomatic event in receptive host rock, possibly related to phreato-magmatic volcanism. The recent identification of ammonium-bearing clay alteration indicates a late volatile phase common to shallow hydrothermal systems. A potential source intrusion has been identified in a feldspar-porphyritic monzonite several kilometres south of the deposit area where regional magnetics (first vertical derivative) show a 6.2 kilometre diameter ring-shaped high.

WORK HISTORY

The Blackwater claim was staked in 1977. Intermittently from 1977 to 1984, Granges conducted geophysical and soil geochemistry surveys. A total of 31 core holes and 34 reverse circulation holes were drilled between 1985 and 1987. They identified 2 areas of mineralization, the Gold and Silver zones. Additional claims were staked in 1985, 1987, 1991 and 1992. Granges conducted detailed geological mapping, geochemical sampling, geophysical surveys (IP, magnetic and VLF-EM) and drilled 5 core holes on the Pem claim. In the mid-1980s, Kerr Addison Mines Limited staked the Dave, Chief and Mary Lou mineral claims adjacent to the Silver zone and the Jon Group, 2.5 kilometres to the south to cover zinc anomalies. Drilling began in 1985 and was concentrated between 1986 and 1994 with a total of 6300 metres completed during this period. A further 1332.6 metres of drilling was completed in the winter of 2005 to 2006.

In 2009, Silver Quest Resources optioned part of the property from Richfield Ventures Corp. In 2010, numerous gold-bearing intercepts at Blackwater-Davidson justified Richfield Ventures Corp. upgrading 20 kilometres of access road, installing a year-round camp and expanding its two year drill program to a planned 50,000 metres. The HQ drilling was on a 50 metre grid and will enable resource estimation in 2011. About 15,500 metres of the program is expected to be done in 2010. A deep-penetration induced polarization survey was completed to help interpretation and drilling. The gold zone straddles the boundary between a claim that is 100 per cent owned by Richfield and one that is 75 per cent owned by Richfield and 25 per cent by Silver Quest Resources Ltd. Later in the year, once Richfield had earned its interest in the joint claim, the drilling focused on the wholly-owned tenure until Silver Quest determines how it wants to manage its interest.

In a March 2, 2011 press release, the companies announced updated resource estimates combined for both the Blackwater and Davidson properties, which listed indicated resources of 53,460,000 tonnes grading 1.06 grams per tonne gold and 5.6 grams per tonne silver and inferred resources of 75,452,000 tonnes grading 0.96 gram per tonne gold and 4.0 grams per tonne silver, calculated using a 0.4 gram per tonne gold cut-off grade (Press Release, Richfield Ventures Corp., March 2, 2011). In June 2011, New Gold Inc. acquired Richfield Ventures Corp. and completed diamond drilling on the property. Highlights include drillhole BW-179, which returned 278 metres grading 2.78 grams per tonne gold (Press Release, New Gold Inc., August 9, 2011).

In 2012, New Gold Inc. released a preliminary economic assessment, which included an updated resource estimate showing indicated resources of 267,100,000 tonnes grading 0.88 gram per tonne gold and 4.3 grams per tonne silver and inferred resources of 120,500,000 tonnes grading 0.69 gram per tonne gold and 7.3 grams per tonne silver calculated using a 0.3 gram per tonne gold cut-off grade (Press Release, New Gold Inc., September 20, 2012). In 2012, the exploration program at Blackwater was the biggest in the province and included resource and geotechnical drilling of over 800 holes comprising about 236,606 metres. Drilling confirmed continuity of mineralization, a higher grade silver zone in the northwest, and extension to the north beyond the 1.1 square kilometre delineation grid. In March, New Gold Inc. expanded their land position near the Blackwater project with the acquisition of Auro and AuroSouth from Gold Reach Resources Ltd.

In 2013, New Gold Inc. released an updated resource estimate using the data from 1002 drillholes totaling 309,509 metres. In this estimate, all material with a gold equivalent cut-off grade of greater than 0.4 gram per tonne is considered for direct processing while all material with a gold equivalent cut-off grade between 0.3 and 0.4 gram per tonne is earmarked to be stockpiled. The estimate shows measured resources of 116,995,000 tonnes grading 1.04 grams per tonne gold and 5.6 grams per tonne silver, indicated resources of 189,044,000 tonnes grading 0.78 gram per tonne gold and 6 grams per tonne silver, and inferred resources of 13,815,000 tonnes grading 0.76 gram per tonne gold and 4.1 grams per tonne silver, calculated using a 0.4 gram per tonne gold equivalent cut-off grade. They also calculated a measured resource of 26,521,000 tonnes grading 0.3 gram per tonne gold and 4.1 grams per tonne silver, indicated resource of 64 382 000 tonnes grading 0.3 grams per tonne gold and 4.4 grams per tonne silver, and inferred resources of 3,785,000 tonnes grading 0.66 gram per tonne gold and 4.0 grams per tonne silver, using a grade cut-off of between 0.3 and 0.4 gram per tonne gold equivalent (Press Release, New Gold Inc., April 4, 2013).

In 2013, intermediate gold producer New Gold Inc. commenced the Feasibility Study (FS) phase for the Blackwater project. All exploration work in support of the FS was completed by April, including over 20,000 metres of geotechnical and condemnation drilling for proposed site facilities north of the deposit, 10 drill holes of oriented core for structural analysis in the proposed pit area, and pump and piezometric well installations. Additional work throughout the year included: geological block model completion; mine design and production scheduling; metallurgical testwork and flowsheet design; mill and related facility design and layouts; grinding circuit design studies; TSF and water management designs, and construction scheduling; power supply connection study and transmission line routing; geotechnical testing for road and air access layouts; and layout designs for construction and permanent camps. The FS built upon the positive PEA study released in September 2012. The PEA study describes an open-pit mining operation with 60,000 tonnes per day (21.9 million tonnes per year) processing plant and a mine life of 16.4 years.

In January 2014, New Gold Inc. released the National Instrument (NI) 43-101 technical report. It describes an open-pit mining operation with 60,000 tonnes-per-day processing plant and a mine life of 17 years. Life-of-mine average annual production would be 12,846 kilograms of gold and 54,182 kilograms of silver. Total metal production would be 217,724 kilograms of gold and 920,663 kilograms of silver.

In June 2015, New Gold Inc. resumed exploration near the Blackwater deposit, focusing on epithermal gold-silver targets up to five kilometres south and west of the deposit in the Blackwater South project area (including the Dave and Kaolinite Ridge target areas). At Blackwater South, exploration consisted of infill induced polarization and magnetic geophysical surveys, and drilling. Work followed up on the 2014 discovery of porphyry-style copper-molybdenum-silver mineralization at the northwest margin of the inferred Blackwater granodiorite pluton (Late Cretaceous), where a resistivity high and chargeability low geophysical anomaly had been targeted. Stockwork quartz veining and quartz-cemented breccia with coarse molybdenite and clots of chalcopyrite-pyrite was intercepted over lengths of 414 metres and 272 metres, and vertical depth of about 460-880 metres. Drilling in 2015 tested a geochemical anomaly coincident with a magnetite destructive linear feature in hornfelsed Bowser Lake Group sedimentary units at the margin of the pluton. About two kilometres north at the Dave target, grassroots work was followed by drilling that targeted a coincident geochemical and geophysical (magnetic low, chargeability high) anomaly following a northeast-trending structure in Kasalka Group volcanic rocks. About 3.5 kilometres to the west, at the Kaolinite Ridge target, grassroots work and a ground magnetic geophysical survey was followed by drilling that tested a northeast trending soil geochemical anomaly with a gold-in-till anomaly in the down-ice direction. The target area is underlain by crystal lithic tuff that is superjacent to the rhyolite flow sequence at Blackwater, and may belong to either the Kasalka Group or Ootsa Lake Formation. Further to the west (13 kilometres) at the Buck prospect (093F 050), a heliborne magnetic survey was completed and grassroots work. The area is underlain by gossanous, hornfelsed tuffaceous sedimentary units and volcanic rocks of the Bowser Lake Group and/or Hazelton Group. A granite pluton was dated as Late Cretaceous, and is considered prospective for gold-mineralized rhyolite dikes or sills.

In 2017, New Gold Inc. is 100 per cent owner of the Blackwater project. It is accessible by existing roads, but development would require construction of a 140 kilometre transmission line from a substation south of Endako (093K 006). The mine operation, once completed, would consist of an open pit, ore processing facility, waste rock dump, tailings pond, water management facilities, offices, employee accommodations, warehouses, and a truck shop. In 2015-17, the company continued advancing its environmental assessment process and coordinated with both federal and provincial governments, with the aim of meeting the requirements for an Environmental Assessment Certificate (EAC) from the Province of British Columbia, and a Decision Statement from the federal Minister of the Environment. In addition, New Gold continued collecting baseline data, completed additional soil and till sampling, and undertook geotechnical work related to mine design. Proven and Probable reserves stand at 8.2 million ounces of gold, and 60.8 million ounces silver. As proposed, Blackwater would be a 60,000 tonnes-per-day operation with a 17-year mine life.

In 2017, proven reserves are 124.5 million tonnes at 0.95 gram per tonne gold and 5.5 grams per tonne silver. Probable reserves are 169.7 million tonnes at 0.68 gram per tonne gold and 4.1 grams per tonne silver. Measured resources are 117 million tonnes at 1.04 grams per tonne gold and 5.6 grams per tonne silver. Indicated resources are 189 million tonnes at 0.78 gram per tonne gold and 6.0 grams per tonne silver (Information Circular 2018-1, page 43).

Bibliography
EMPR EXPL 1977-E185; 1979-214; 1980-321; 1982-288,289; 1985-C290; 1988-C155; 1992-69-106; 1998-B-3
EMPR FIELDWORK 1992, pp. 475-481; 1993, pp. 9-14, 39-44, *45-55; 1994, pp. 167-170, 171-176, 193-197, 199-205; 1999, pp. 173-184
EMPR OF 1994-19; 1995-10; 1995-16; 1998-10
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N MINER Nov.1-7, 2010; Apr.12, 2011
PR REL Southern Rio Resources Ltd., Apr.27, Jun.8, Nov.3, 2005; Richfield Ventures Corp., Sept.18,21,28, Oct.16, Nov.18, 2009; Apr.20, Jun.8,22, Jul.26, Aug.16-22, Sept.2,28, Oct.20, Nov.2,22,23, 2010; Jan.2,12,25, Feb.8, Mar.*2,15,14-20, May 3, Jun.27, Sept.19, Nov.27, 2011; Silver Quest Resources Ltd., Jan.20, Mar.2, Apr.5,19, 2006; Oct.29, 2009; Jan.6, May 7, 2010; Apr.19, May 10, Sept.19, 2011; New Gold Inc., Aug.*9, 2011; Mar.7, Apr.17, Jul.18, Sept.*20,28, 2012; Feb.5, Apr.*4, Dec.*12,13, 2013; Feb.4, Apr.29, 2015; Feb.*17, 2016

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