Associations and parageneses of microelements in coal

Resumo

Microelements present in coal may be chemically bound with organic matter or with mineral impurities (clastic and authigenic minerals). Analytical data present the total (gross) content of microelements in coal. Such microelements are generally present in associations. In addition, some chemical elements accumulate in the coal on account of their content in organic matter; they constitute a paragenesis. In predicting the content of rare metals in coal deposits and in their extraction from the coal, it is important to establish the parageneses of the microelements—in other words, to distinguish the parageneses from associations of microelements. Such microelements may create anomalous concentrations in the coal. The present work establishes the characteristics of associations and parageneses of microelements in coal and proposes a statistical method for distinguishing parageneses from associations. The method is illustrated for data regarding Baikal coal deposits; it proves very effective.