Depreciation: Stanley Coal Mines Facts Cost of crane $600,000 Estimated useful life 10 years Estimated salvage value $100,000 Productive life in hours 50,000 hours Calculate the first year depreciation. (Activity Method) If Stanley uses the crane for 4,000 hours the first year, the depreciation charge is? Straight-Line Method? Sum-of-the-Years-Digits? Declining-Balance Method (Double Declining)?