In the article “Unconventional Grading” in your August issue, you have made an outstanding contribution to the prevailing confusion about the relationship of the metric system to other systems of weights and measures. The word ounce derives from the Latin word uncia, which means one- twelfth. Thus, the Roman or Troy ounce is one-twelfth of a pound. The English or Avoirdupois ounce is one- sixteenth of a pound. The troy ounce is subdivided into 20 pennyweights. The avoirdupois ounce is subdivided into 16 drams. The Apothecary system of weights and measures was devised by medieval apothecaries to measure small doses of medication. The grain was originally the weight of a grain of wheat taken from the middle of the ear. There are 480 grains in a troy ounce, 437.5 grains in an Avoirdupois ounce.
Daily quotations on the price of gold are given in U.S. dollars per troy ounce. Assayers report the gold content of rock in troy ounces per ton of 2,000 pounds.
The metric system is based on the metre, which is one-10-millionth of the distance from the equator to the poles. It was introduced by the French in 1797 following the French Revolution. A centimetre is one-hundredth of a metre. The gram (or gramme) is the unit of weight and is the weight of one cubic centimetre of water.
The relationship of the metric to other systems is roughly as follows:
— one metre is 39.37 inches
— one troy ounce is approximately 38 grams
— one gram is approximately 0.028 troy ounces
— one gram per tonne is roughly 0.03 troy ounces per ton
Geologists and other people with scientific training have recently shown a tendency to report gold concentrations in grams per tonne. A tonne is a thousand kilograms (or a million grams) and is equal to 2,240 pounds. If your geological consultant reports gold content in this way, you are justified in asking him or her also to report it in troy ounces per ton since that is the way the price of gold is quoted. Forty-one parts per million (or 41,000 parts per billion) is roughly equal to one troy ounce per ton. Lorne E. Ross, President, Taseko Mines. Interest in Knelson It was with great interest that I read the article titled “Towards the Perfect Mill” in the August issue. In particular, I would like to learn more about the Knelson concentrator since it seems to represent a better approach to gravity separation. Could you please provide me with a contact name, address or phone number. Eric Konigsmann, Chief Metallurgist, Hemlo Gold Mines (Editor’s Note: The Knelson concentrator is sold by Knelson International Sales Inc., 20313-86 Ave., R.R. #11, Langley, B. C., V3A 6Y3, (604) 888-4000 or (604) 421-3255.) Lupin Story Praised Allow me to congratulate you and your team on an outstanding issue of The Northern Miner Magazine this past August. The article on the Lupin gold mine, especially, is a good example of thoughtful, in-depth writing — the kind of coverage for which your magazine is becoming renowned. I was a contract worker on the Lupin project during startup, so I was grateful for being updated as to how this fascinating gold producer is progressing.
Your new publication just keeps getting better and better. Keep up the good work. Robert Forster, North Bay, Ont.
In the article “Unconventional Grading” in your August issue, you have made an outstanding contribution to the prevailing confusion about the relationship of the metric system to other systems of weights and measures. The word ounce derives from the Latin word uncia, which means one- twelfth. Thus, the Roman or Troy ounce is one-twelfth of a pound. The English or Avoirdupois ounce is one- sixteenth of a pound. The troy ounce is subdivided into 20 pennyweights. The avoirdupois ounce is subdivided into 16 drams. The Apothecary system of weights and measures was devised by medieval apothecaries to measure small doses of medication. The grain was originally the weight of a grain of wheat taken from the middle of the ear. There are 480 grains in a troy ounce, 437.5 grains in an Avoirdupois ounce.
Daily quotations on the price of gold are given in U.S. dollars per troy ounce. Assayers report the gold content of rock in troy ounces per ton of 2,000 pounds.
The metric system is based on the metre, which is one-10-millionth of the distance from the equator to the poles. It was introduced by the French in 1797 following the French Revolution. A centimetre is one-hundredth of a metre. The gram (or gramme) is the unit of weight and is the weight of one cubic centimetre of water.
The relationship of the metric to other systems is roughly as follows:
— one metre is 39.37 inches
— one troy ounce is approximately 38 grams
— one gram is approximately 0.028 troy ounces
— one gram per tonne is roughly 0.03 troy ounces per ton
Geologists and other people with scientific training have recently shown a tendency to report gold concentrations in grams per tonne. A tonne is a thousand kilograms (or a million grams) and is equal to 2,240 pounds. If your geological consultant reports gold content in this way, you are justified in asking him or her also to report it in troy ounces per ton since that is the way the price of gold is quoted. Forty-one parts per million (or 41,000 parts per billion) is roughly equal to one troy ounce per ton. Lorne E. Ross, President, Taseko Mines. Interest in Knelson It was with great interest that I read the article titled “Towards the Perfect Mill” in the August issue. In particular, I would like to learn more about the Knelson concentrator since it seems to represent a better approach to gravity separation. Could you please provide me with a contact name, address or phone number. Eric Konigsmann, Chief Metallurgist, Hemlo Gold Mines (Editor’s Note: The Knelson concentrator is sold by Knelson International Sales Inc., 20313-86 Ave., R.R. #11, Langley, B. C., V3A 6Y3, (604) 888-4000 or (604) 421-3255.) Lupin Story Praised Allow me to congratulate you and your team on an outstanding issue of The Northern Miner Magazine this past August. The article on the Lupin gold mine, especially, is a good example of thoughtful, in-depth writing — the kind of coverage for which your magazine is becoming renowned. I was a contract worker on the Lupin project during startup, so I was grateful for being updated as to how this fascinating gold producer is progressing.
Your new publication just keeps getting better and better. Keep up the good work. Robert Forster, North Bay, Ont.
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