Reader Rebuttal (February 01, 2003)
Quebec’s non-metal mines left out
It seems like you have forgotten us or made a translation mistake on page 28 of your September 2002 issue [map of the geological subdivisions and location of active mines in Quebec in 2001]. The map is not coherent with its legend; the title should be “Geological subdivisions and location of active metal mines in Quebec in 2001”.
If you want to keep the title then you would have to include other mines including the chrysotile asbestos mines of the Thetford Mines mining camp. I am working for L.A.B. Chrysotile’s Bell Operation, which started in 1878 and is an underground mine extracting close to 7,000 tonnes/day of ore by block caving. We are still mining chrysotile asbestos and are proud to contribute to the economic wealth of the region, the province and the country.
Jean Garant, production engineer L.A.B. Chrysotile Inc., Bell Operations Thetford Mines, Que.
Bring provincial maps into the 21st century
There are large amounts of valuable geological data in older geological maps, but they are presented in patterns that do not lead prospectors to think along the lines of our current geological understanding of the Earth’s crust.
It seems to me that the provincial geological surveys could make a significant contribution to the development of their natural resources by re-issuing geological maps with a 21st century interpretation. Aside from production and distribution costs, this could be done on a rather reasonable cost basis because it consists primarily of “brain-power” based on field spot-checking to confirm rock types.
Many years ago, I noticed that four of the largest volcanoclastic massive sulphide (VMS) deposits in the Canadian Precambrian Shield lie on a straight line, namely the Horne, Kidd Creek, Geco and Mattabi mines. My curiosity led to drawing this line on a geological map and identifying other areas of felsic volcanic activity along this lineament, which might deserve further prospecting.
Along the extension of this lineament, I picked the largest areal extent of volcanic rock that had not yet yielded a significant discovery. Fortunately this area has good geological maps, Ontario government airborne survey coverage, and good road access. Therefore, I was able to advance my prospecting to specific targets in a relatively short time. A lot of pick and shovel prospecting, mobile metal ion soil testing, geological mapping and rock breaking to pursue airborne targets, produced abundant bedrock observations.
Federal and provincial geological maps provided excellent factual information about outcrop location, rock types and structural field observations. Certain rock types that aroused my curiosity were re-classified after field-checking, but generally these maps were reliable and invaluable.
My experience was that Canadian geologists have been sound observers and recorders of the facts. We can rely on their identification of rocks and structures on a consistent basis, although today we may not agree with their structural interpretations. Older geological maps provide a structural interpretation consistent with the geosynclines, geanticlines and isoclinal fold structures that predominated during the last century. They do not relate to concepts of island arc geology, ocean bottom black smokers, subducted continental margins and crustal spreading being developed today.
In my prospecting area, for example, I have changed what was interpreted 20-40 years ago as a single isoclinally folded normal sequence of felsic and mafic volcanic rocks, to a double sequence with a major unconformity between the two volcanic types. This change of interpretation, which was inspired by reading recent crustal studies, has changed my priorities for prospecting airborne geophysical anomalies.
New ideas are of limited use if they are not available for the front-line explorers to use.
I would like to see the old concepts of geological interpretation replaced in the provincial database by new concepts at a reasonable cost. These reinterpretations would provide prospectors with the latest ideas of where to look for mineral deposits.
Lionel Kilburn, prospector Oakville, Ont.
How about them diamonds?
I read your column about Canadian diamonds [“Doing Some Digging, p. 5, CMJ December 2002] with great interest. I gather from your article that there is a premium attached to GNWT designation. I am assuming that at least part of that premium has to do with the fact that certification assures you aren’t getting a conflict diamond.
How do Canadian diamonds compare purely in terms of quality with offshore (e.g., South African) diamonds–i.e., is the raw value of the stone as great (understanding that there are doubtless all kinds of gradations of quality)? In the end analysis, would a very well cut Canadian diamond be “as good as” or worth as much as a very well cut South African diamond?
Steve Mitchell Toronto, Ont.
The premium pays for the additional paperwork in tracking the stones from the mine to the store, and for a Northwest Territories agent to make a detailed description and evaluation of each stone. Whether people are willing to pay a premium for this, will be decided by the marketplace. Some will want a Canadian stone because it is Canadian, and others will want it because it is not a conflict diamond.
Canadian stones, both rough and cut, are certainly worth as much as stones from South Africa or anywhere else. In fact, the two Canadian diamond mines are recovering stones that have a higher per-carat value than from most other mines in the world, because there is a higher percent of gem-quality colourless diamonds. I am told that the quality standards at the Yellowknife cutters is high, but you should remember that Yellowknife has only had a diamond cutting industry since 1998 and so far there are only a handful of master cutters who were trained in Canada.