主题：【原创】日益枯竭的煤炭资源，走向深渊的中国经济 -- hwd99

21 Recoverable reserves are those quantities of coal which geological and engineering information indicates with reasonable certainty can be extracted in the future under existing economic and operating conditions. Because recoverable reserves are a subset of total coal resources, recoverable reserve estimates for a number of countries, including China and the United States, could increase substantially as coal mining technology improves and as additional geological assessments of the coal resource base are completed. The reserves-to-production ratio is based on the reserves estimates and data on world coal production for 2006 shown in Table 9.