(Courtesy of Wayne Goodfellow) larger image [JPEG, 100.4 kb, 440 X 294, notice]

(Courtesy of Wayne Goodfellow) larger image [JPEG, 162.4 kb, 440 X 322, notice]

As a direct employer of about 2000 people, the Bathurst mines have been a critical part of northeastern New Brunswick's economy. Because the ore bodies were rapidly depleting, the EXTECH-II project in the Bathurst Mining Camp was begun in 1994. This project, involving a partnership of industry, universities, NB Department of Natural Resources, US Geological Survey and GSC led to the discovery the Camelback base metal deposit. Because of market conditions, this deposit is not currently commercial, but may be in the future. (EXTECH project)

Figure 1. General geology of the Bathurst Mining Camp and major volcanic-sediment hosted massive sulphide (VSHMS) deposits. larger image [JPEG, 359.0 kb, 1200 X 1543, notice]

Synopsis

The EXTECH II project in the Bathurst Mining Camp was initiated in 1994 because, without the discovery of new reserves, production would start to decline and, with it, the principal source of economic activity in northeastern New Brunswick. The project has delivered new geological, geophysical and geochemical data for exploration in the Bathurst area through a partnership involving industry, universities, New Brunswick Department of Natural Resources, United States Geological Survey and several divisions of the Geological Survey of Canada. An external evaluation of the impact and effectiveness of the project rated it highly. EXTECH-II resulted in an increase in exploration expenditures in the Bathurst area of $2-3 million per year over the life of the project, and higher levels of expending are expected to continue for 7-10 years. At the end of the project, the Bathurst Mining Camp will have the most comprehensive, publicly accessible geoscience database of any mining camp in the world. This knowledge infrastructure will support exploration for many years to come, and will greatly increase the probability of discovery of new base metal reserves.

Rationale

Mining is a growing and increasingly technologically-sophisticated industry that exerts a major impact on the Canadian economy. In 2002, mineral exports alone totaled $49.4 billion and the industry employed over 360,000 Canadians in over 400 communities across Canada. Over 2200 Canadian-based companies sell specialized scientific and technical equipment and services to the mining industry. Canada ranks first in the world in exploration expenditures and ranks in the top five in the production of Ni, Zn, Pt, Au, Mo, Cu, Pb and Cd. However, to sustain this industry and the communities it supports, new mineral reserves will have to be found by improving the geoscience infrastructure in frontier areas and by developing new and improved methods of detecting ore deposits at depth in mature mining districts.

Approach

The Bathurst EXTECH project represents an integrated and multidisciplinary approach to mineral exploration research. It encourages synergy among specialists in the various fields of geology, geophysics and geochemistry by focusing their efforts on understanding a specific deposit-type in a specific mining camp. Expertise and synergy are enhanced by linking federal, provincial, university and industry scientists in a single project. The nominal goal is to develop an integrated deposit exploration model - a model that incorporates the geological, geophysical and geochemical signatures and vectors for the deposit-type. The integrated model will assist in renewed exploration and resource assessments. In working toward this goal, the regional geoscience knowledge base of the mining camp is enhanced, generic and specific technologies are developed or improved, and the data, technologies and models are transferred through collaboration, workshops and publications to various client groups.

Figure 2. Generalized stratigraphic columns showing the age and lithostratigraphy of deposits hosted by different blocks and formations in the Bathurst Mining Camp. Notes: Flat Landing Brook (FLB) and Nepisiguit Falls (NFF) formations, Tetagouche Group; Spruce Lake (SLF), Mount Brittain (MBF) and Canoe Landing Lake (CLLF) formations, California Lake Group; Clearwater Stream Formation (CSF), Sheephouse Brook Group. larger image [JPEG, 413.6 kb, 1000 X 655, notice]

Mineral Resources

The Bathurst Mining Camp is one of Canada's most important base metal mining districts, accounting in 2001 for 30% of Canada's production of Zn, 53% of Pb, and 17% of Ag. The value of production from the Bathurst Mining Camp in 2001 exceeded $500 million and accounted for 70% of total mineral production in New Brunswick. Approximately 2000 people are directly employed by the mining industry in the Bathurst area. Ten Bathurst Mining Camp massive sulphide deposits have been brought into production with a total production to 1999 of 128 million tonnes with an average grade of 2.87 wt % Pb, 6.58 wt % Zn, 0.93 wt % Cu, and 82 g/t Ag. Only the Brunswick No.12 deposit is currently in production. In addition, 0.337 million tonnes of Cu have been mined from the Caribou supergene zone, and 1.254 million tonnes of Au from the Caribou, Murray Brook and Heath Steele gossans.

Geoscience

The Bathurst deposits are an economically important sub-group of seafloor hydrothermal deposits that are hosted by both sedimentary and bimodal volcanic rocks. The Bathurst Mining Camp has been subdivided into four approximately coeval groups of volcanic and sedimentary rocks - Tetagouche, California Lake, Sheephouse Brook and Fournier groups - and together these groups host all the major massive sulphide deposits in the Camp (Figure. 1 and Figure. 2). The Bathurst Mining Camp is interpreted to have formed in a Sea of Japanese style back-arc basin, referred to as the Tetagouche-Exploits back-arc basin, that opened by rifting of continental crust in the Early Ordovician (Figure. 3).The tectonic blocks represent different parts of this back-arc basin that were tectonically juxtaposed in a west-dipping subduction complex. Most Bathurst deposits probably formed in local fault-controlled third-order basins within the Tetagouche rift during periods of felsic volcanism. Four hydrothermal events spanning about 14 million years have been recognized, and from oldest to youngest are: Chester (478 Ma), Caribou (472-470 Ma), Brunswick/Heath Steele (469-468 Ma) and Stratmat (467-465 Ma) horizons.

Figure 3. Hydrothermal and tectonic models, Bathurst Mining Camp. (a) detailed cross-section of the hydrothermal system; (b) back-arc continental rift setting. larger image [JPEG, 460.1 kb, 800 X 1002, notice]

Geophysics and geochemistry have played an important role in the discovery of massive sulphide deposits in the Bathurst Mining Camp. As part of the EXTECH-II project, a multiparameter (magnetic, electromagnetic and radiometric), helicopter-supported and high-resolution survey was flown over the entire camp to support geological mapping of the Camp, and to stimulate exploration by identifying new targets for mineral exploration (e.g. Figure. 4). This survey led to the discovery of the Camelback base metal deposit.

Figure 4. Total magnetic field of the Bathurst Mining Camp generated data collected by a helicopter survey at 200 m line spacing . Also shown is an outline of the geology and massive sulphide deposits in the Camp. larger image [JPEG, 358.3 kb, 650 X 597, notice]

Outcomes

Results have been delivered by a series of papers, Open File releases, talks, workshops and field trip guidebooks. Final summary papers and maps were published in 2002 in Economic Geology Monograph 11 entitled "Massive sulfide deposits of the Bathurst Mining Camp and Northern Maine" edited by W.D. Goodfellow, S.R. McCutcheon and J.M. Peter.

The following are conclusions of an external impact assessment of the EXTECH-II project:

• EXTECH resulted in an increase in exploration expenditures in the Bathurst camp of $2 -3 million/year over the life of the project and this level of additional spending is expected to continue for at least 7 - 10 years following its completion. Thus, the combined expenditure of $6.5 million of the federal and provincial governments has stimulated incremental expenditures of $24 - 45 million by industry.
• At the end of the project, Bathurst will have the most comprehensive, publicly accessible digital geoscience data base of any mining camp in the world. This will serve the area for many years to come and greatly increase the probability of discovery of new base metal reserves.
• EXTECH II was a very effective program. It ranks the highest among nine similar evaluations conducted by the consultant over the past seven years. Its success owes in large part to its multidisciplinary approach, the effective integration of the efforts of federal and provincial geoscientists, the close partnership with mining and exploration companies active in the area, and the use of sate-of-the-art geographical information technology to integrate, display and interpret multi-parameter geoscience data.

Participants

The project involved over 40 geoscientists from the Geological Survey of Canada, New Brunswick Department of Natural Resources, U.S. Geological Survey, the university community, Minerals and Mining Sector, New Brunswick Productivity Council, Atlantic Canada Opportunities Agency, and industry.

More Information

More information can be obtained from the over 200 papers, maps and databases published in Economic Geology Monograph 11, GSC and DNR open files and reports, and journals, and from the EXTECH II: Bathurst Mining Camp N. B. web site.