储量定义美国资源局精.docx

1、储量定义美国资源局精192APPENDIX AAbbreviations and Units of Measure1 carat (metric (diamond = 200 milligrams1 flask (fl = 76 pounds, avoirdupois1 karat (gold = one twenty-fourth part1 kilogram (kg = 2.2046 pounds, avoirdupois1 long ton (lt = 2,240 pounds, avoirdupois1 long ton unit (ltu = 1% of 1 long ton or

2、22.4 pounds avoirdupoislong calcined ton (lct = excludes water of hydrationlong dry ton (ldt = excludes excess free moistureMcf = 1,000 cubic feet1 metric ton (t = 2,204.6 pounds, avoirdupois or 1,000 kilograms1 metric ton (t = 1.1023 short ton1 metric ton unit (mtu = 1% of 1 metric ton or 10 kilogr

3、amsmetric dry ton (mdt = excludes excess free moisture1 pound (lb = 453.6 grams1 short ton (st = 2,000 pounds, avoirdupois1 short ton unit (stu = 1% of 1 short ton or 20 pounds, avoirdupoisshort dry ton (sdt = excludes excess free moisture1 troy ounce (tr oz = 1.09714 avoirdupois ounces or 31.103 gr

4、ams1 troy pound = 12 troy ouncesAPPENDIX BDefinitions of Selected Terms Used in This ReportTerms Used for Materials in the National Defense Stockpile and Helium StockpileUncommitted inventory refers to the quantity of mineral materials held in the National Defense Stockpile. Nonstockpile-grade mater

5、ials may be included in the table; where significant, the quantities of these stockpiled materials will be specified in the text accompanying the table.Authorized for disposal refers to quantities that are in excess of the stockpile goal for a material, and for which Congress has authorized disposal

6、 over the long term at rates designed to maximize revenue but avoid undue disruption of the usual markets and financial loss to the United States.Disposal plan FY 2011 indicates the total amount of a material in the National Defense Stockpile that the U.S. Department of Defense is permitted to sell

7、under the Annual Materials Plan approved by Congress for the fiscal year. FY 2011 (fiscal year 2011 is the period October 1, 2010, through September 30, 2011. For mineral commodities that have a disposal plan greater than the inventory, actual quantity will be limited to remaining disposal authority

8、 or inventory. Note that, unlike the National Defense Stockpile, helium stockpile sales by the Bureau of Land Management under the Helium Privatization Act of 1996 are permitted to exceed disposal plans.Disposals FY 2011 refers to material sold or traded from the stockpile in FY 2011.Depletion Allow

9、anceThe depletion allowance is a business tax deduction analogous to depreciation, but which applies to an ore reserve rather than equipment or production facilities. Federal tax law allows this deduction from taxable corporate income, recognizing that an ore deposit is a depletable asset that must

10、eventually be replaced.193 APPENDIX CReserves and ResourcesReserves data are dynamic. They may be reduced as ore is mined and/or the extraction feasibility diminishes, or more commonly, they may continue to increase as additional deposits (known or recently discovered are developed, or currently exp

11、loited deposits are more thoroughly explored and/or new technology or economic variables improve their economic feasibility. Reserves may be considered a working inventory of mining companies supply of an economically extractable mineral commodity. As such, magnitude of that inventory is necessarily

12、 limited by many considerations, including cost of drilling, taxes, price of the mineral commodity being mined, and the demand for it. Reserves will be developed to the point of business needs and geologic limitations of economic ore grade and tonnage. For example, in 1970, identified and undiscover

13、ed world copper resources were estimated to contain 1.6 billion metric tons of copper, with reserves of about 280 million metric tons of copper. Since then, about 400 million metric tons of copper have been produced worldwide, but world copper reserves in 2011 were estimated to be 690 million metric

14、 tons of copper, more than double those in 1970, despite the depletion by mining of more than the original estimated reserves. Future supplies of minerals will come from reserves and other identified resources, currently undiscovered resources in deposits that will be discovered in the future, and m

15、aterial that will be recycled from current in-use-stocks of mineral or from minerals in waste disposal sites. Undiscovered deposits of minerals constitute an important consideration in assessing future supplies. USGS reports provide estimates of undiscovered mineral resources using a three-part asse

16、ssment methodology (Singer and Menzie, 2010. Mineral-resource assessments have been carried out for small parcels of land being evaluated for land reclassification, for the Nation, and for the world.Reference CitedSinger, D.A., and Menzie, W.D., 2010, Quantitative mineral resource assessmentsAn integrated approach: Oxford, United Kingdom, Oxford University Press, 219 p.Part AResource/Reserve Classification for Minerals