MODEL FOR DETERMINING THE COST-BENEFIT OF MODIFYING CLEAN COAL SAMPLING PROGRAMS.

The primary objective of this study is to determine if altering the sampling program, by differing sampling decision rules, can result in tighter quality control of a preparation plant's clean coal output, and if so, to determine if it is economically desirable to do so. The basic trade-off that must be investigated is the product gain possible by altering the sampling program and the increased cost of sampling and analysis. To aid in the analysis of this trade-off between product gain and sampling and analytical costs, a computer model has been developed. Given the sampling history of a plant under study, the program analyzes the plant's current sampling scheme. Applying systematic decisions on sampling frequency based on results of previous sample analysis by the use of the Markovian Chain Theory and other statistical and mathematical techniques, new sampling schemes can be modeled and compared using economic considerations. Through this method, it may be found that for a given plant, overall economics can be improved by altering the sampling program, most likely by requiring additional sampling. Effects of premiums and penalties, as well as sampling and analytical costs on plant economics are also included. An example of the model's use will conclude the paper.