Not Amused

I am disgusted at the attitude displayed in your editorial entitled “Our Man at Thompson” [see December 1990 issue]. The licence that you took describing the city of Thompson in the way that you did is beneath contempt.

To correct your facts: While Inco has one of its mines near our city, Thompson is not a “nickel operation.” It is a city of 15,000 people who exist in their own right. It is also not 400 miles north of civilization. Thompson has almost every amenity that civilized people normally expect, including every retail facility, a university campus, clean air and regular visits from a world-renowned ballet company and symphony. I cannot think of anything that you have in Don Mills that is more representative of civilization than these. We do not have gridlock, smog and commuting time.

As a voice for the mining industry, your magazine has a responsibility to present factual information about mining to the public.

Distortion of the facts for a cheap joke does credit to neither you nor the mining industry. If you cannot maintain high journalistic standards, we cannot complain about the political misunderstandings you regularly discuss in your publications.

You mentioned that this was your first visit to Thompson. Perhaps if you visited the communities that you represent more often, you would have a better grasp of the relevant facts. If you cannot manage an apology and cheap jokes are the best you can do, I would suggest that you do not visit us again.

David Shefford,

Chairman,

Thompson Industrial Commission,

Thompson, Man.

Distorted Perception

Although we appreciate The Northern Miner Magazine’s coverage of Inco’s Manitoba division, some of us were dismayed at the editorial reference to Thompson being “. . . 400 air miles north of civilization.”

This twist of phrase unfortunately reinforces a distorted perception many people have of northern lifestyles. Indeed, we pride ourselves on the quality of life enjoyed in such resource-based communities where people thrive both materially and intellectually. We are not 400 air miles north of civilization, but rather 400 air miles north of Winnipeg.

G. Daniel McSweeney,

Superintendent, Public Affairs,

Inco Ltd.,

Thompson Division

Editor’s note: With reference to the preceeding letters, the phrase “north of civilization” was a figure of speech that was used to emphasize the latitude of the Thompson operation. It was not intended to be taken literally; nor was it meant as a “cheap joke” upon the residents of Thompson.

Mixed Signals

Graham Clow’s article on “Why Gold Mines Fail,” in the February issue, is a timely warning to all whose enthusiasm gets ahead of their realism. But I had to smile when he advises “cut stray high assays if they cannot be properly explained, since most gold deposits are cursed with some degree of nugget effect.” Turning back a few pages in the same issue brought me to James (or was it Moses?) Wade’s “10 Commandments of Mine Feasibility,” the sixth of which is: “Thou shalt not adulterate the grade by cutting indiscriminately erratic high-grade values.”

Now, who are we going to believe? From an assayer’s viewpoint, they are both right, but we had all better clearly understand why, if we are to get out of this cycle of confusion. The nugget effect is simply caused by taking too small a sample to represent the whole, nothing more, nothing less. It will always show up when the laboratory has been asked to do the impossible — which is to get a 30-gram fire assay to represent 2 to 3 kg of nuggety rock.

Opening a mine based on “nuggety” 30-gram fire assays should only be done by cutting grades like crazy, and then you’ll probably be pleasantly surprised at your mill recoveries. But if you are working with a marginal property (is there any other kind these days?), then apply Wade’s sixth commandment and get serious about sample size or you may be cutting the mine as well as the grade.

Our answer to the problem has been to run the whole sample through a cyanide leach to dissolve all the nuggets and then fire-assay the residues. The total gold value reported is both free of any nugget effect and higher (by 10% to 30%) than single fire assays.

George Duncan, President,

Accurassay Laboratories,

Kirkland Lake, Ont.