The Hearne Hill deposit is located just south of Hearne Hill, east of the south end of Morrison Lake, approximately 70 kilometres northeast of Smithers.
The property is underlain by northwest trending massive andesite flows, tuffs and epiclastic sedimentary rocks of the Lower to Middle Jurassic Telkwa Formation (Hazelton Group). These are in fault contact with greywacke, argillite and conglomerate of the Jurassic to Cretaceous Ashman Formation (Bowser Lake Group). A small dioritic to quartz dioritic stock of the Triassic to Early Jurassic Topley Intrusions has intruded the layered rocks and is in turn intruded by a small biotite feldspar porphyry plug (BFP) and associated northeast trending dike swarm of the Eocene Babine Intrusions. Copper and gold mineral deposits in the Babine Lake district are associated with the BFP intrusions.
At the Hearne Hill property there are two types of copper-gold - molybdenum - silver deposits, as follows, a) a stockwork porphyry copper of the general Babine-type, and b) breccia bodies containing enriched copper-gold mineralization (known as the Chapman and Peter Bland zones) situated within a high grade core zone of the porphyry deposit.
In the BFP intrusions and surrounding Hazleton volcanic country rock, chalcopyrite, pyrite and molybdenite occur as fracture fillings, as disseminations and within stockwork quartz veinlets. The hostrocks contain biotite and quartz-sericite alteration. Alteration zoning from fresh unaltered porphyry through propylitic, phyllic and potassic is present within the porphyry deposit.
The volcanic rocks are locally strongly silicified and termed "hybrid diorite". Biotite alteration is associated with the best copper mineralization, and sericite-pyrite alteration is found peripheral to the copper mineralization. Porphyry copper-style, fracture controlled and disseminated chalcopyrite, bornite and minor molybdenite mineralization, estimated to average 0.2 per cent copper (Assessment Report 20084), is found in highly fractured "hybrid diorite" and in the porphyry plug. A breccia pipe, approximately 50 by 60 metres in size, cuts the porphyry copper mineralization and is mineralized with chalcopyrite. One drillhole in the breccia pipe assayed 2.75 per cent copper across 22.9 metres (Assessment Report 20084).
The breccia bodies are situated within and adjacent to the porphyry copper stockwork. The Chapman and Peter Bland zones are separated by approximately 300 metres, have a 010 to 030 degrees strike, and appear to dip steeply (70-80 degrees) to the east. The breccias consist of angular clasts up to several tens of centimetres size of BFP and Hazelton volcanics. Open space in the breccia prior to mineralization is estimated at 5 to 20 per cent of rock volume. Chalcopyrite, pyrite and carbonate minerals were deposited in the space between the angular clasts.
Work History
Historically, Trojan Consolidated Mines Ltd. and the Buttle Lake Mining Company Limited acquired 363 claims in the Kofit, Reg, ML, Marc, and Cram groups. These claims, held jointly by the two companies, surround the Morrison property (093M 007). Tro-Buttle Exploration Limited, which is controlled by the above companies, began exploration work on the property in 1967. Geophysical and geochemical surveys and bulldozer trenching located mineralization on the Kofit group on Hearne Hill. Texas Gulf Sulphur Company optioned the property in 1967 and during the latter part of the year carried out geophysical and soil geochemical surveys, and 1942 metres of diamond drilling in 12 holes. The option was subsequently dropped. The Chapman breccia zone was first discovered in 1967.
In 1968, Canadian Superior Exploration Limited optioned the property and work during 1968 and 1969 included geological mapping, electromagnetic, induced potential, geochemical soil surveys, and percussion drilling in 47 holes totalling 3353 metres near the base of Hearne Hill.
Additional diamond drilling and exploration work was completed by Canadian Superior Explorations in 1986-88 and Noranda-Bell in 1989-90 (11 holes totalling 1366 metres). The best intersection intersected 2.75 per cent copper over 22.9 metres in 1989 (Property File Rimfire - Weary, 1998) and 24.4 metres grading 0.67 per cent copper and 0.05 per cent molybdenum in 1990 (Property File Placer Dome - Ogryzlo, 1991). In 1991, Dave Chapman completed seven diamond-drill holes totalling 550 metres in the Breccia zone.
Previous drill indicated and inferred reserves in the main breccia body (Chapman breccia zone) located within a large, low grade porphyry system are 180,000 tonnes grading 1.7 per cent copper (Information Circular 1994-1, page 18).
The level of sampling information at Hearne Hill as of December 31, 1992 was much lower than for the Morrison deposit and rigorous resource calculations were not appropriate. The resource estimates for stockwork mineralization at Hearne Hill were performed by first calculating 12.5 metre bench composites from the diamond drill area. The diamond drill composites were then kriged and contoured, and volumes calculated within each contour to a depth of approximately 100 metres. Resource estimates for breccia mineralization were calculated by constructing polygons on-section to the confines of the breccia pipe.
As of December 31, 1992, the inferred resource for the Hearne Hill porphyry deposit was estimated to be 60 million tonnes at an average grade of 0.16 per cent copper and 0.1 gram per tonne gold using a cut-off grade of 0.10 per cent copper. The breccia pipe (Chapman) within the Hearne Hill porphyry deposit, to a depth of 100 metres, was estimated to contain an indicated resource of 143,000 tonnes at an average grade of 1.73 per cent copper and 0.8 gram per tonne gold using a cut-off grade of 0.75 per cent copper (CIM Special Volume 46, page 300).
In 1993, Booker Gold acquired the property and complete 12 diamond-drill holes in 1994. These extended the low grade porphyry mineralization 250 metres to the east of the previous limit.
During 1994 and 1995, drilling approximately 200 metres to the northwest of the Chapman zone located a new zone called the Peter Bland zone, a second breccia body of high grade copper-gold-silver mineralization. This zone is estimated to be 500 metres in length, 200 metres in width and at least 460 metres in depth. This new zone is reported to be lithologically identical to the Chapman zone and the two may connect at depth. Over the next two years, drilling in the vicinity of the Chapman zone produced the highest copper and gold grades to date on the property. This included a 3-metre section grading 17.75 per cent copper and 11.14 grams per tonne gold (Property File Rimfire - Weary, 1998)
Between October 1995 and October 1996, 58 NQ diamond-drill holes were drilled between by Booker Gold for a total of 14,684 metres. The 1996 program of Booker Gold was reported to prove that the porphyry system on the Hearne Hill property is of larger dimensions than previously inferred and contains at least three copper-gold volcanic breccia zones with grades of 0.4 to 5 per cent copper and 0.1 to 3 grams per tonne gold (1997 Cordilleran Roundup Abstracts, page 35). One drillhole at this time (95-16) assayed 0.75 per cent copper and 0.32 gram per tonne gold over its entire length of 299.4 metres (Property File Rimfire - Morrison, 1995).
Between October 1996 and October 1997, 69 NQ diamond-drill holes were completed for a total 15,957.20 metres. In 1997, Booker Gold conducted an extensive surface trenching mapping and sampling program. Six kilometres of trenches were excavated, exposing approximately 4.3 kilometres of bedrock. The bedrock was sampled and mapped in detailed and used to produce a 1:1000 geological map. In 1996 and 1997, Booker Gold was successful in extending the Bland and Chapman zones. Drilling in the vicinity of the Chapman zone produced the highest copper and gold grades to date on the Hearne Hill property (17.75 per cent copper over 1 metre, 11.14 grams per tonne gold over 3 metres), and extended the zone both at depth and to the southeast (Assessment Report 25287).
As of January 31, 1998, Booker Gold had completed 143 diamond-drill holes on the property and determined the Bland and Chapman zones contain an indicated resource of 4,230,000 tonnes grading 0.6 per cent copper and 0.186 gram per tonne gold, at a 0.3 per cent copper cut-off; and an inferred resource of 947,000 tonnes grading 0.408 per cent copper and 0.183 gram per tonne gold, at a 0.3 per cent copper cut-off (Press Release - Booker Gold Explorations Limited, July 7, 1998).
In late 2003, Pacific Booker Minerals Inc. retained Beacon Hill Consultants to prepare a scope of work and cost estimate to complete a full feasibility study on the Morrison/Hearne Hill porphyry copper/gold projects and estimates that the feasibility study will take 15-18 months to complete. Preliminary stages of environmental and geotechnical programs have been in progress during the past six months as data for these activities are collected over extended periods, or are co-ordinated with continuing drilling programs (Press Release - Pacific Booker Minerals Inc., December 5, 2003).
In 2019, John Kreft completed a program of biogeochemical and geochemical (rock and soil) sampling on the Hearne Hill property. Two rock samples (1907937 and 1907939) yielded greater than 1.00 per cent copper each, 2.9 and 7.1 grams per tonne silver and 0.197 and 0.252 gram per tonne gold, respectively (Assessment report 38541).