CRITERIA AND SIZE OF ESTONIAN OIL-SHALE RESERVES

There are several criteria for determining mineable oil shale reserves and resources. Three characteristics: thickness, average calorific va lue, and depth of the mineable bed were used in the era of planned eco nomies, based on available mining technology capabilities. The reserve cut-off values had been estimated mostly for the needs of the large p ower industry. A research project to find new characteristics for the determination of oil shale reserves which are compatible with today's economy was performed in 1996/1997. According to this study, a given o il shale bed is defined as a reserve, provided that the costs of ifs m ining and delivery to the consumer are lower than the consumer's expen diture of coal procurement. This study also defines an oil shale bed w ith an energy rating above 25 GJ/m(2) as a resource. Using these crite ria, Estonia's oil shale resources are over 6 billion tonnes, or over 47 EJ (EJ - 10(18) J) of energy, including active reserves exceeding 2 billion tonnes, with over 17 EJ of energy.