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The Ashanti Belt has the longest history of gold mining and is consequently the most understood of Ghana's gold belts. The area was the focus for gold exploitation in pre-colonial times when small scale artisanal mining extracted gold for traditional authorities whose culture attached great significance and value to the metal. From the late 19th century, conventional mining and extractive methods were employed by British companies, leading to the development of deeper underground mines at Obuasi, Tarkwa, Prestea, Marlu, Abosso, Konongo and many other smaller shafts and adits developed on mineralization on the Ashanti Belt. These mines remained the focus of gold production in Ghana for much of the colonial era. After independence the government nationalized the industry and most of the mines were then run by state mining corporations. Insufficient development capital resulted in the deterioration of mining infrastructure, decreasing production and failing profitability of most of the operations. The advent of a new Mining Code and privatization of the state run mines in 1992 led to an injection of investment capital to replace infrastructure at old mines and funded a resurgence of exploration using modern techniques. The focus of the bulk of this activity was on the Ashanti Belt and led to very significant extensions of resources at Obuasi, Tarkwa and Prestea. New world class deposits were discovered and developed at Obuasi, Tarkwa, Iduapriem, Teberebie, Bogosu, Damang, and Akyem on the Ashanti Belt so that the Ashanti Belt now has an aggregated gold endowment (past production + resources and reserves) in excess of 125,000,000 ounces of gold. This is undoubtedly one of the world's premier gold belts.
The geology of the Ashanti Belt comprises coeval Lower Proterozoic Systems of Birimian (2.17 - 2.18 billion years old) metavolcanic and metasedimentary rocks uncomfortably overlain by younger Tarkwaian epiclastic metasediments. The Birimian and Tarkwaian lithologies have been intruded by two distinctive granite types, older and larger basin-type Cape Coast granitoids and the younger belt-type Dixcove granitoids. The belt is elongated northeastward, extending from the coast at Axim to the Voltaian escarpment near Konongo, where the Birimian lithogies are covered by younger sediments. The belt has been subjected to multiple deformation events giving rise to several phases of folding and faulting. The most significant structures are the major northeast trending marginal structural corridors which tend to host most of the major orogenic gold deposits.
There are two styles of gold mineralization encountered on the Ashanti Belt. Typical shear zone hosted deposits are focussed on the aforementioned marginal structures and on splays of these structures. Deposits of this type on the Ashanti Belt include Obuasi, Konongo, Prestea, Bogosu, Damang, Akyem, Salman, Anwia, Wassa, Mampon, Sian and Konongo. The other deposit type is the Witwatersrand-style conglomerate hosted deposits. Examples of this deposit type on the Ashanti Belt include Tarkwa, Abosso, Teberebie and Iduapriem.
The belt has been extensively explored over the last 15 years and could arguably be considered a mature exploration area. However major, mid-tier and junior companies continue to extend known resources and discover new deposits, which have the potential to develop into new standalone operations or supplementary resources for the many infrastructure hubs that are spread along the length and breadth of the Ashanti Belt.
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