Читать книгу Coal-Fired Power Generation Handbook - James Speight G., James G. Speight - Страница 22

The coal reserves and resources of the world are difficult to assess because of the lack of accurate data for individual countries. Two fundamental problems make these estimates difficult and subjective. The first problem concerns differences in the definition of terms such as proven reserves (generally only those quantities that are recoverable) and geological resources (generally the total amount of coal present, whether or not recoverable at present).

Thus, in any text dealing with coal, there must be recognition, and definition, of the terminology used to describe the amounts, or reserves of coal available for recovery and processing. But the terminology used to describe coal (and for that matter any fossil fuel or mineral) resource is often difficult to define with any degree of precision (Speight, 2011b, 2014, 2020).

Different classification schemes (Chapter 2) often use different words which should, in theory, mean the same but there will always be some difference in the way in which the terms can be interpreted. It might even be wondered that if the words themselves leave much latitude in the manner of their interpretation, how the resource base can be determined with any precision. The terminology used here is that more commonly found although other systems do exist and should be treated with caution in the interpretation.

Generally, when estimates of coal supply are developed, there must be a line of demarcation between coal reserves and resources. Reserves are coal deposits that can be mined economically with existing technology, or current equipment and methods. Resources are an estimate of the total coal deposits, regardless of whether the deposits are commercially accessible. For example, world coal reserves were estimated to be in excess of one trillion tons (1 x 10¹² tons) and world coal resources were estimated to approximately 10 trillion tons (10 x 10¹² tons) and are geographically distributed in Europe, including all of Russia and the other countries that made up the former Soviet Union, North America, Asia, Australia, Africa, and South America (Table 1.7).

However, there are definitions that go beyond reserves and resources. To begin at the beginning, the energy resources of the Earth are subdivided into a variety of categories (Figure 1.4) and the resources of coal (as well as each of the other fossil fuel resources) can be further subdivided into different categories (Figure 1.5) (Speight, 2013, 2014, 2020).