Troy weight them Holland troy, Paris troy, etc. Their values varied from one another by up to several percentage points. Troy weights were first used in England in the 15th century, and were made official for gold and silver in 1527. The British Imperial system of weights and measures (also known as Imperial units) was established in 1824, prior to which the troy weight system was a subset of pre-Imperial English units. The troy ounce in use today is essentially the same as the British Imperial troy ounce (1824–1971), adopted as an official weight standard for United States coinage by Act of
Imperial Metals Corp Imperial Metals Corp Imperial Metals Corporation known as IMI Imperial Metals Inc until 2002, is a Canadian metals and mining company. Engaging in the acquisition, exploration, development, mining, and production of base and precious metals in North America, the majority of its holdings and operations are in British Columbia. In 2016 the Company produced 119.17 million pounds of copper, 94,930 ounces gold and 330,960 ounces silver from its Mount Polley and Red Chris mines. Imperial has two operating mines in British Columbia, one in southern Nevada, and two exploration stage projects also in British Columbia currently under development. The Mount