Another worry: a worldwide shortage of tellurium, which is produced as a mining by-product, to fuel First Solar's long-term growth.

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Most of the mining companies that Silver Wheaton works with produce silver as a by-product of their mining operations and so is a win-win arrangement for both the participating companies.

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All seven economists insist that their results are not the product of data-mining crunching the numbers in search of any interesting pattern they can find.

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Mine supply for silver is rising faster than for other metals, helped by an increase of by-product from gold-mining operations plus a number of major primary projects in recent years.

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Daughter Jean has focused on mining the Internet to market and sell their product.

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Silver is actually a by-product of the gold and lead mining, there are few, if any, active mines that mine only silver.

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Silver Wheaton signs long-term purchase agreements with mining companies (typically gold and copper mining companies) that produce silver as a by-product.

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Since their product is so prized, gold miners tend to trade at even higher valuations than diversified mining firms.

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