D. "wet basis" means ore in its natural wet state.

The key parameters of the oil shale resource appraisement consist of ore-bed recoverable thickness(H), orebody effective area(S), orebody weight(D) and orebody resource types, etc.

The copper ore leaching had been put into practice with a history of about 1000 years and was once well-developed in Soong Dynasty (960-1279 A. D. ) .