436 ECONOMIC GEOLOGY Characteristics of Economic Mineral Deposits The AGI Glossary of Geology defines economic geology as ‘‘the application of geologic knowledge and theory to the search for and the understanding of mineral deposits; study and analysis of geologic bodies and materials that can be utilized profitably by man, including fuels, metals, non-metallic minerals, and water’’ In this work (Encyclopedia) water and hydrocarbon fuels are treated separately in view of their major industrial and economic importance The solid mineral resources also fall into specialist groups, as indicated in the definition quoted above Collectively, they comprise the non-renewable resource base of the extractive industries To qualify for ‘‘profitable utilisation by man’’ they must all demonstrate certain characteristics that are, appropriately, both economic and geological Geological Attributes of Economic Deposits The size (tonnage) must be sufficient to sustain exploitation for a period long enough (mine life) to justify development The valuable content (grade) must be high enough to repay all costs Taken together, the tonnage and average grade express the comparative geological potential of the deposit The shape, attitude, depth and physical properties of the deposit must be amenable to extraction by existing mining technology The valuable constituent(s) must be amenable to separation from the unwanted portions (waste), and beneficiation to marketable product by existing technologies the seven attributes listed reveals that the risk of financial failure is shared between measurable geological, engineering and logistical natural factors on the one hand and indefinite state-imposed constraints or incentives on the other Economic geologists need a sound appreciation of mineral economics, mining engineering and mineral processing technology, but their core expertise rests upon their knowledge of mineral deposits Figure illustrates the hierarchical progression from mineral occurrence to mineral prospect to mineral deposit, and then through mineral resources and proved mineral reserves to profitable mining This progression rests for its success, above all else, on the quality of geological observation and interpretation, and its application in industry It is important also to appreciate that the mines of today are exploiting only those selected deposits that have met all the criteria for current economic development They represent only the tip of the iceberg of the Earth’s mineral resources Large deposits of many mineral commodities, currently identified but subeconomic, may in future become payable because of improvements in mining or mineral extraction technology, commodity demands and prices, and similar conditions Those deposits may one day join the stock of future discoveries that will provide the economic deposits and mines of tomorrow Economic Attributes of Economic Deposits The price received for the product(s) must cover all production costs and assure competitive advantage The geographical situation must be amenable to mine development, including water and power supplies; and within economic transport distance to market, especially for bulky products Socio-political conditions must be favourable These include planning permission and mineral rights, various taxes and royalties, labour and safety laws and conditions, regulations for waste disposal, and rehabilitation when the mine is worked out A new mining development is typically capital intensive with a lead-time of years between discovery and profitable production Brief consideration of Figure The progression from a mineral prospect to mineral extraction Expenses increase as work becomes more detailed Mine development requires capital expenditure before cash flow starts from mineral product sales The categories of resources and reserves, and the technical terms proved, probable, meas ured, and indicated are strictly defined in codes of practice for mulated by professional mining institutions in some leading mining countries (Australia, Canada, South Africa, UK/Europe, and USA) and accepted by financial organizations such as stock exchanges