Summary of Significant Accounting Policies (Tables) |
12 Months Ended | ||||||||||||
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Dec. 31, 2016 | |||||||||||||
| Accounting Policies [Abstract] | |||||||||||||
| Estimated Useful Life of Assets | Property and equipment and depreciation – We state property and equipment at cost, including capitalized interest on borrowings during the actual construction period of major capital projects. Capitalized interest costs were $2.9 million in 2014, $1.1 million in 2015 and $.9 million in 2016. We compute depreciation of property and equipment for financial reporting purposes (including mining equipment) principally by the straight-line method over the estimated useful lives of the assets as follows:
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