The Morrison deposit is located 21 kilometres north of the Bell mine (MINFILE 093M 001), north of Babine Lake and 86 kilometres east of Hazelton.
Siltstone, silty argillite and minor conglomerate of the Middle to Upper Jurassic Ashman Formation (Bowser Lake Group) are host to small Eocene Babine Intrusions, including biotite-hornblende-plagioclase porphyry plugs, sills and dikes.
In this area, the Ashman Formation sedimentary rocks are intruded by a multiphase Eocene biotite-hornblende-plagioclase porphyry plug (BFP). The sediments are massive and strongly altered so bedding is not visible. Where observed, bedding generally strikes north to northwest and dips steeply. The siltstones and argillites are very fine to medium-grained and their overall appearance and mineralogy depend largely on their location in the alteration zones. Fawn or medium grey colours and clastic textures are characteristic of rocks with considerable introduced carbonate at the outer portions of the property. The rocks become darker greyish green and fawn, indurated, chlorite-carbonate–rich greywackes and argillites as the copper zone is approached; in the copper zone, these are dark grey and jet-black biotitized. Conglomerates are evident at a few localities distant from the porphyry plug. Throughout the entire property, the sediments are cut by abundant biotite-hornblende-plagioclase porphyry dikes and sills. Light tan-coloured, medium to fine-grained rhyodacite dikes with aplitic textures occur locally. Postmineral andesitic dikes have been encountered in drillholes.
The Morrison is a strongly zoned, annular porphyry copper deposit that is largely within the multiphase porphyry plug. The main porphyry pluton is a faulted plug with nearly vertical contacts, which occupies a northwest-oriented elliptical area of 900 by 150 to 300 metres. Before faulting, the plug was roughly circular in section, with a diameter of approximately 500 metres. Numerous offshoots of the plug, many of which are north-trending dikes or sills, occur throughout the host sedimentary rocks. The offshoots, most with sharp contacts, vary in width from less than 1 metre to greater than 500 metres. The plug contains a large number of phases, whose presence is indicated by the abundance of phenocrysts and groundmass grain sizes. Some of these variations occur over distances of only a few metres. Part of this variation in appearance is due to superimposed hydrothermal alteration.
The Morrison deposit occupies the central part of a major graben that is a component of the regional northwest-trending block-fault system of this area. The western bounding fault is believed to be along Morrison Lake, and the eastern fault is approximately 800 metres east of the property. The most prominent structure at Morrison is the north-northwest–trending Morrison fault, which bisects the porphyry plug and copper zone. The fault is apparently vertical and has a right-hand throw of approximately 300 metres. The vertical displacement, although unknown, is believed to be considerable. Rather than a single break, the fault is a linear zone of parallel shears and fractures. The zone averages approximately 25 metres in width but ranges from 50 metres in the central portion to only a few metres at the extremities.
Along its entire length, the Morrison fault is marked by intense clay-carbonate alteration and well-defined zones of carbonate-cemented gouge and breccia. North-northwest–trending streaks and patches of clay-carbonate alteration found elsewhere in the intrusive plug and surrounding rocks are believed to have developed along minor shears and fractures that formed along contacts and bedding planes during movements on the fault.
The Morrison copper zone is a vertical annular cylinder that conforms to the shape of the porphyry plug and is disrupted by the Morrison fault, which bisects the zone along its low-grade core. The copper zone is defined by external and internal boundaries marking the limits of rock that consistently grades greater than 0.3 per cent copper. In most places, the external boundary is relatively sharp and copper grades decline outward to less than 0.1 per cent within approximately 40 metres. The low-grade core averages between 0.15 and 0.2 per cent copper. Between the internal and external 0.3 per cent isopleths, copper increases fairly regularly to form a higher grade annulus. In the 15 to 150-metre-wide annulus, copper exceeds 0.5 per cent. Maximum grades over appreciable widths are approximately 0.7 per cent copper. Along the Morrison fault is a linear zone, 5 to 20 metres wide, in which downgrading to approximately 0.2 to 0.25 per cent copper has occurred. This is due to mixing and diluting sheared rock during fault movements and to leaching by late hydrothermal solutions and possibly by groundwater. In the high-grade annulus, molybdenum averages approximately 0.01 per cent whereas gold and silver average 0.3 gram per tonne and 3 grams per tonne, respectively. Spotty occurrences of galena and sphalerite, in carbonate-cemented brecciated veins within and near the fault and in smaller parallel shears, contribute to relatively high yet uncommercial values of lead and zinc.
Chalcopyrite and pyrite are the main sulphides. Locally, minor to moderate amounts of bornite contribute significantly to copper grades; however, most of the high-grade sections owe their copper content solely to chalcopyrite. All rocks contain anomalous quantities of pyrite (greater than 1 per cent) but the most pronounced concentrations (5 to 15 per cent by volume) occur in three segments that surround the copper zone. Most of the chalcopyrite occurs along thin seams and veinlets with or without quartz and is distributed chiefly in fracture stockworks, but approximately 20 to 30 per cent of the mineral is disseminated in the porphyry plug matrix and in peripheral sedimentary rocks. Very minor molybdenite occurs in some chalcopyrite-pyrite seams and as minute disseminated flakes. Pyrrhotite and marcasite occur only in minor amounts. Pyrrhotite occurs almost exclusively in the pyrite halo. Marcasite is most commonly associated with pyrite, arsenopyrite, galena, sphalerite, geocronite and boulangerite. These minerals occur with quartz and carbonate in small vuggy veinlets and pockets in minor faults and in the clay-carbonate altered rocks of the Morrison fault zone. Locally, exposed copper minerals are altered to malachite, brochantite and small amounts of an unidentified pale blue copper silicate. Some iron-bearing sulphides are altered to iron oxides and minor jarosite.
Detailed polished section studies indicate that pyrite and chalcopyrite have a well-defined zonal relationship. Although pyrite predominates in the pyrite halo, the 0.3 per cent copper isopleth precisely marks a change in pyrite to chalcopyrite ratios; chalcopyrite consistently exceeds pyrite inside this boundary. Although the absolute abundance of pyrite decreases toward the centre of the deposit, disseminated grains persist throughout the copper zone and in the low-grade core. These studies have also shown that magnetite and minor bornite are present in the low-grade core and the copper zone (that is, the area enclosed by the 0.3 per cent copper isopleth).
Hydrothermal alteration is characterized by biotite-chlorite zoning. Biotitization is directly related to copper grades; chloritization is strongest in peripheral, pyritized rocks. The deposit is within a centrally located biotite zone; the intensity decreases outward. Surrounding the biotite zone is a chlorite-carbonate zone. Intense clay-carbonate alteration is associated predominantly with the Morrison fault and related shears and is superimposed on the earlier biotitic and chloritic alteration. Minor epidote is found in all parts of the property but is most common in the outer chlorite-carbonate zone. A potassium-argon age date from hydrothermal biotite from the mineralized zone returned 52.1 million years (Bulletin 64, p. 142).
Minor amounts of well-crystallized chlorite occur in the biotite zone, mainly as veinlets and crystal clusters. Finer, less strongly crystallized chlorite is common in the weak outer part of the zone. Abundant chlorite, occurring mainly as pseudomorphs after hornblende, and sericite characterize the chlorite-carbonate zone. The biotite to chlorite ratio increases as the copper zone is approached, as does the crystallinity of both minerals. Potassium feldspar is evident in very minor amounts in the inner, greater than 0.3 per cent copper portion of the copper zone; gypsum also occurs locally. Disseminated fine-grained apatite is anomalously abundant in the porphyry plug and in some large dikes. Very minor amounts of tourmaline were observed in thin sections of the intrusive and sedimentary rocks near the western edge of the mineralized zone.
The Morrison deposit and its concentric sulphide-silicate alteration zones were formed during a single hydrothermal episode that followed the emplacement and crystallization of most of the phases of the biotite-hornblende-plagioclase porphyry plug (Canadian Institute of Mining and Metallurgy [CIM] Special Volume 15).
Geological resources published in 1976 give a reserve of 86 million tonnes grading 0.42 per cent copper (0.3 per cent copper cutoff), 0.34 grams per tonne gold and 3.4 grams per tonne silver (CIM Special Volume 15, 1976, p. 264).
Indicated and inferred resources for the Morrison deposit as of December 31, 1993, total 190 million tonnes grading 0.4 per cent copper and 0.21 gram per tonne gold to a depth of 300 metres, using a cutoff grade of 0.3 per cent copper. An open-pit resource developed on the basis of a 0.75 to 1 waste to ore strip ratio and the same cutoff grade is estimated at 58 million tonnes grading 0.41 per cent copper and 0.21 gram per tonne gold (CIM Special Volume 46, p. 300).
The Morrison deposit is owned by Noranda Mining and Exploration Inc. and Booker Gold Explorations Ltd. See also Hearne Hill (MINFILE 093M 006).
A drill-indicated resource for the Morrison showing was reported in July 1998 as 123 200 000 tonnes grading 0.38 per cent copper and 0.203 gram per tonne gold, at a 0.3 per cent copper cutoff (Press Release, Booker Gold Explorations Limited, July 7, 1998).
The Morrison Lake area was first explored in the early 1960s during the initial rush of exploration to the Babine region. Regional stream sediment sampling in 1962 by the Norpex Group of Noranda Exploration Company Limited led to the discovery of the Morrison deposit in 1963. During follow-up exploration in 1963 of copper-anomalous stream sediments collected in 1962, copper-bearing biotite (hornblende) plagioclase porphyry (BFP) float and exposures were found by employees of Noranda Exploration Company Limited in the stream flowing over the copper zone. Trenching of the thin overburden uncovered relatively unweathered chalcopyrite-bearing bedrock in large areas on both sides of the stream, where soil samples were anomalous.
Ninety-five diamond drill holes, most oriented east or west with a dip of 045 east, were drilled from 1963 to 1973. The first 65 holes were AEX diameter; the remaining 30 were BQ diameter. Induced polarization surveys were not definitive because of widespread pyrite; however, the BFP intrusions, including portions of the BFP plug, were known to contain abundant magnetite. As a result, magnetic surveys were used as a guide in the early drilling. By 1968, a sub-economic deposit had been outlined that consisted of two zones totalling approximately 55 million tonnes averaging 0.42 per cent copper. The zones are immediately northwest and southeast of the small central pond, and their positions correspond closely to strong geochemical and magnetic anomalies.
Geological mapping done in 1963 and 1967 had indicated the possibility that the two zones might comprise a single faulted deposit. Hydrothermal alteration studies initiated in 1967 showed that the deposit had well-defined biotite-chiorite zoning and that biotitization was very closely related to copper grades. Although data were sparse, biotitization in the large, poorly tested area between the two known zones appeared to be widespread and strong, indicating that this area was probably underlain by additional (plus) 0.4 per cent copper mineralization. Drilling in 1970 tested the central area and succeeded in joining the portions of the faulted copper zone, increasing the known tonnage of the deposit from approximately 55 to 86 million tonnes.
The Morrison copper zone and peripheral hydrothermally altered rocks have resisted erosion by glaciation more than the surrounding unaltered rocks. The altered rocks occur in an elevated, thinly mantled, roughly elliptical plateau 60 to 90 metres above the level of Morrison Lake. This plateau is bisected by a north-south gully carved along the East Fault and is surrounded by areas of shallow to very deep glacial overburden.
It is significant to note that following the 1973 drill program, Noranda did no further fieldwork at Morrison. Pit design studies were carried out in 1988 and 1990 to establish whether Morrison could supply feed to the Bell mine, but no further drilling was done on the property until Booker Gold Exploration (now Pacific Booker Minerals Inc.) initiated a two-phase exploration program in 1998. The main features of each phase were as follows (as per Assessment Report 26410).
A 1999 diamond drill hole ended at 307 metres depth (the drill’s maximum capability), still in rock mineralized with chalcopyrite and bornite. The hole was deepened in 2000 to 466.56 metres. The grade, consistent throughout the hole, averaged 0.7 per cent copper and 0.4 gram per tonne gold (George Cross Newsletter #100, May 3, 2000). Mineralization is open to depth. In 2001, Pacific Booker Minerals Inc. continued diamond drilling to drill off the Morrison deposit.
In 2002, Pacific Booker Minerals Inc. completed its three-year program of 60-metre grid drilling of the Morrison porphyry copper deposit by drilling 5578 metres in 20 diamond drill holes and subsequently released an open-pit resource calculation. Based on 82 holes (22 824 metres of drilling) and a 0.3 per cent copper cutoff, an independent consultant estimated the Morrison deposit contains a measured plus indicated resource of 62 121 000 tonnes at 0.46 per cent copper and 0.22 gram per tonne gold, and an inferred resource of 8 937 000 tonnes at 0.52 per cent copper and 0.21 gram per tonne gold (Exploration and Mining in BC 2002, p. 6).
In 2003, the project entered the environmental assessment process with a proposal to develop a 20 000 to 25 000-tonne per day open-pit mine. Measured plus indicated reserves were determined by E. Kimura, P.Geo., to be 12.4 million tonnes at 0.53 per cent copper and 0.26 gram per tonne gold (at 0.3 per cent copper cutoff and 0.75 strip ratio) in a starter pit, within an ultimate pit of 62.1 million tonnes grading 0.46 per cent copper and 0.22 gram per tonne gold (at 0.3 per cent copper cutoff and 1.15 strip ratio; Exploration and Mining in BC 2003, p. 13). To close gaps in the resource base and for hydrologic and geotechnical assessment, Pacific Booker drilled eight holes (totalling 2420 metres) in 2003, bringing the total number of drillholes in the Morrison deposit to 90.
In 2004, Pacific Booker Minerals Inc. continued to collect environmental baseline data and contracted a preliminary economic study related to the potential development of the property. Optimized open-pit resources were estimated at 86 892 000 tonnes grading 0.45 per cent copper and 0.257 gram per tonne gold (Exploration and Mining in BC 2004, p. 33). Waste rock is estimated at 125 million tonnes, giving a waste to ore ratio of 1.44. Approximately 97 per cent of the mineral resources is classified as measured and indicated, and the remainder is inferred. Included in the waste are 28 152 000 tonnes grading 0.278 per cent copper and 0.123 gram per tonne gold that would be placed on a low-grade stockpile and processed subject to prevailing metal prices.
In 2005, Pacific Booker advanced the project by drilling 700 metres of P-size core to recover a metallurgical test sample and a further four holes totalling approximately 1000 metres to complete resource definition.
In 2007, activity resumed on the Morrison copper-gold project after a one-year hiatus. Pacific Booker Minerals Inc. completed geotechnical drilling to assess tailings impoundment sites and metallurgical and engineering work—all related to a feasibility study expected to be complete by year end. The project report for a 30 000-tonne per day open-pit mine is expected in mid-2008. The measured plus indicated resource was given as 206 869 000 tonnes grading 0.39 per cent copper, 0.2 gram per tonne gold and 0.005 per cent molybdenum. Projected metal recoveries are approximately 86 to 88 per cent for copper, 60 per cent for gold and 50 per cent for molybdenum (Exploration and Mining in BC 2007, p. 12).
In 2008, Pacific Booker Minerals Inc. advanced the Morrison copper-gold project, meanwhile trying to engage the Lake Babine First Nation. A program of geotechnical and hydrogeology drilling and test-pitting was completed. Metal leaching and acid generation test work continued, and environmental fieldwork was completed.
A geotechnical feasibility study was completed by Klohn Crippen Berger Ltd. in January 2009, based on a 30 000-tonne per day open-pit mine with a conventional milling plant and a tailings facility located approximately 3 kilometres northeast of the open pit. Updated resource estimates were included in a March 2009 technical report for Pacific Booker. Combined measured and indicated resources reported were 208 250 000 tonnes grading 0.39 per cent copper, 0.19 gram per tonne gold and 0.005 per cent molybdenum, calculated using a 0.3 per cent equivalent copper cutoff (Robertson, J, 2009).
The final application for provincial environmental assessment certification was submitted in mid-2010 and, in August 2012, Pacific Booker received an unsigned environmental assessment certificate upon completion of the review stage. In September 2012, the Government of British Columbia refused to issue an environmental assessment certificate for the Morrison project; as a result, the company’s federal environmental assessment application was put on hold in October 2012. In the spring of 2013, Pacific Booker filed a petition with the Supreme Court of British Columbia to set aside the September 2012 decision denying the Morrison Copper-Gold Project application for an environmental assessment certificate.