Revision History for Circular 930-O U.S. Geological Survey International Strategic Mineral Issues Summary Report--Tungsten First posted online in 1998 Revised and reposted in November 2014, as Circular 930-O, version 1.1 Revisions by John H. DeYoung, Jr., and Kim B. Shedd of the U.S. Geological Survey After publication in 1998 of U.S. Geological Survey (USGS) Circular 930-O, "International Strategic Mineral Issues Summary Report--Tungsten," inconsistencies between resource data for tungsten deposits in table 10 and the list of the 10 largest deposits in the world (in terms of tungsten content) in table 2 were examined and determined to be the result of errors in both tables. The 10 largest deposits listed in table 2 (on page 12) are based on tungsten content of resources in the R1 and R2 categories (explained in figure 1 on page 3) as presented in table 10 (on pages 50-65). A revised table 2 for page 12 is presented below, and a PDF file of the table is linked from the index Web page for this report. Table 2. Ten largest tungsten deposits or groups of deposits in the world. [This table does not include the Searles Lake brine/evaporite deposit in the United States, from which tungsten cannot be recovered profitably. Contained tungsten is calculated from resource data in table 10. Contained tungsten for individual deposits may not add to total shown owing to rounding] _____________________________________________________________________________________________________ Deposit name (province) Country Contained tungsten (thousand metric tons) _____________________________________________________________________________________________________ Verkhne-Kayrakty (Dzhezkazgan Oblast)................Former Soviet Union [Kazakhstan] 872 Shizhuyuan (Hunan)...................................China 497 Mactung (Yukon Territory and Northwest Territories).......................................Canada 434 /1 Lianhuashan (Guangdong)..............................China 317 Tyrnyauz (former Kabardin-Balkar A.S.S.R.)...........Former Soviet Union [Russia] 242 Logtung [Northern Dancer] (Yukon Territory)..........Canada 167 Yangchuling (Jiangxi)................................China 159 Xingluokeng (Fujian).................................China 142 Damingshan (Guangxi).................................China 115 Vostok-2 (Primor'ye).................................Former Soviet Union [Russia] 101 _____ Total.............................................................................. 3,050 _____________________________________________________________________________________________________ 1/Contained tungsten based on resource data (R1M, R1S, and R2S) from 1981 source listed in table 10. Contained tungsten based on resource data (R1M) from 1986 source listed in table 10 is 177 thousand metric tons. In this revised table 2, the conversion factor used to convert tungsten trioxide (WO3) to contained tungsten (W) was 0.7931, not 0.8 as was apparently used in the original study. Resource quantities in tables 2 and 10 are shown in thousands of metric tons (that is, in kilotons [kt]). 1) The largest deposit, Verkhne-Kayrakty (in Kazakhstan, which was part of the former Soviet Union), is shown in table 10 (on page 63) as having 1,100 kt of R1 resources at 0.128 percent WO3. The "R1" in table 10 should be "WO3"; that change results in the tungsten content of the deposit being calculated as 872 kt (1,100 kt x 0.7931 = 872 kt W). The corresponding R1 resources would be 859,000 kt (1,100 kt divided by 0.00128). If the 1,100 kt represented R1 resources and not WO3, the deposit would contain only about 1 kt of tungsten (1,100 kt x 0.00128 x 0.7931 = 1.12 kt W). 2) The contained tungsten for the Mactung deposit (in Canada) has been revised from 617 kt to 434 kt. In table 2 of the original report, the estimate for R1M resources from a 1986 source (179 kt W) was added to the R1M + R1S + R2S total from a 1981 source (438 kt W), thus double counting the R1M resources (179 kt W). When the double-counted resource is not included, and the more precise conversion factor is used, the revised tungsten content of the resource, based on data from table 10 (on page 52), is 434 kt (57,000 kt x 0.0096 x 0.7931 = 434 kt W). 3) Table 10 (on page 54) shows that the R1 resources of the Lianhuashan deposit (in China) are 40,000 kt at 1 percent WO3. This represents 317 kt of contained tungsten, ranking the deposit fourth in the revised table 2. It was not included in table 2 of the original report. As a result of this addition, the Ta'ergou deposit (in China), formerly ranked number 10, is not included in the revised table 2. The identification of these inconsistencies and the preparation of a revised table 2 resulted from attention brought to the largest deposit list (table 2) when it was cited by Pitfield and Brown (2011, p. 15) and Silberglitt and others (2013, p. 41). These reports listed the 12 largest tungsten deposits based on contained tungsten data for the 10 deposits in table 2 of USGS Circular 930-O and more recent resource data for the Hemerdon deposit in the United Kingdom (309 kt W; was 60 kt W in USGS Circular 930-O) and the O'Callaghan's deposit in Western Australia, which was discovered in mid-2008 (Pitfield and Brown, 2011, p. 15). The revised table 2 in this revision history is based on the data in table 10 of USGS Circular 930-O. No attempt has been made to update the data in table 10. For example, there are more recent resource estimates for Hemerdon (see above) and Mactung (estimates calculated to Canada's National Instrument 43-101 standards result in indicated plus inferred resources of 382 kt WO3 or 303 kt W per Wardrop Engineering, Inc., 2009, p. 1-2 to 1-3). Also, recent discoveries, such as O'Callaghan's (see above) or recent development of previously discovered deposits, such as at the Sisson deposit in New Brunswick, Canada (221 kt WO3 or 175 kt W; see Northcliff Resources Ltd., 2013) contain sufficient resources to be considered in a listing of large tungsten deposits. In addition, no attempt has been made to correct other parts of Circular 930-O (abstract, text, tables, figures, or maps) that may have been based on the original table 2. In addition, the presentation of the resource data in table 2 with three significant digits implies greater precision than is inherent in resource estimates. The annual USGS Mineral Commodity Summaries report presents reserve and resource estimates with no more than two significant digits (U.S. Geological Survey, 2014). Acknowledgment The authors gratefully acknowledge the counsel of W. David Sinclair, economic geologist at the Geological Survey of Canada and a coauthor of Circular 930-O, for sharing his recollection of the construction of table 2 in that publication and for providing examples demonstrating the reasons that recent resource numbers may not be comparable to those of the original report. Some of these reasons are new information on the discovery of deposits after Circular 930-O was prepared (mid-1980s) and released (1998), reevaluation of deposits that were identified when the data were compiled, changes in resource reporting standards, and differences among applications of those standards in different countries. References Cited Northcliff Resources Ltd., 2013, Development/history [of the Sisson deposit]: Vancouver, British Columbia, Canada, Northcliff Resources Ltd., accessed June 4, 2014, at http://www.northcliffresources.com/s/Development.asp. Pitfield, Peter, and Brown, Teresa, 2011, Tungsten [commodity profile]: Keyworth, Nottingham, United Kingdom, British Geological Survey, 33 p., accessed June 3, 2014, at http://www.bgs.ac.uk/downloads/start.cfm?id=1981. Silberglitt, Richard, Bartis, J.T., Chow, B.G., An, D.L., and Brady, Kyle, 2013, Critical materials--Present danger to U.S. manufacturing (prepared for the National Intelligence Council): Santa Monica, Calif., RAND Corporation, document RR-133-MC, 46 p. [Also available at http://www.rand.org/pubs/research_reports/RR133.html.] U.S. Geological Survey, 2014, Mineral commodity summaries 2014: U.S. Geological Survey, 196 p., accessed June 4, 2014, at http://minerals.usgs.gov/minerals/pubs/mcs/2014/mcs2014.pdf. Wardrop Engineering, Inc., 2009, Amended technical report on the Mactung property, document no. 1053390100- REP-R0001-00, prepared for North American Tungsten Corporation, Ltd.: Vancouver, British Columbia, Canada, Wardrop Engineering, Inc., [372] p., accessed June 4, 2014, at the SEDAR (System for Electronic Document Analysis and Retrieval) Web site at http://www.sedar.com/. Suggested Citation of USGS Circular 930-O, Version 1.1 Werner, A.B.T., Sinclair, W.D., and Amey, E.B., 2014, International strategic mineral issues summary report-- Tungsten (ver. 1.1, November 2014): U.S. Geological Survey Circular 930-O, 74 p., http://pubs.usgs.gov/circ/0930/o/. [Supersedes version 1.0 published in 1998; revisions in 2014 by John H. DeYoung, Jr., and Kim B. Shedd.]