Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 54 | Metric tons of gross weight | NA |
| 2003 | 78 | Metric tons of gross weight | 44.44% |
| 2004 | 45 | Metric tons of gross weight | -42.31% |
| 2005 | 146 | Metric tons, gross weight | 224.44% |
| 2005 | 146 | Metric tons of gross weight | 0.00% |
| 2006 | 150 | Metric tons of gross weight | 2.74% |
| 2006 | 16 | Metric tons, gross weight | -89.33% |
| 2007 | 31 | Metric tons, gross weight | 93.75% |
| 2008 | 8 | Metric tons, gross weight | -74.19% |
| 2009 | 45 | Metric tons, gross weight | 462.50% |
| 2009 | 45 | Metric tons of gross weight | 0.00% |
| 2010 | 57 | Metric tons of gross weight | 26.67% |
| 2011 | 58 | Metric tons of gross weight | 1.75% |
| 2012 | 58 | Metric tons of gross weight | 0.00% |
| 2013 | 58 | Metric tons of gross weight | 0.00% |
