In an effort to discourage mining companies from speculating in mineral recovery, the Zimbabwean government has hiked diamond and coal exploration fees, the African Business Review reports.

Diamond companies seeking to explore in Zimbabwe are now charged a fee of $1 million, 20 times the former price of an exploration license, and the price of a coal exploration license has been raised by a factor of five to $100,000.

Companies and individuals are holding onto mining claims without working them, said Deputy Minister of Mines and Mining Development Gift Chimanikrie. "We want serious investors in the mining sector."

In addition to some of the world's richest diamond deposits, Zimbabwe has enormous resources of other valuable minerals. A document prepared by the Zimbabwe Investment Authority last month reported that the country has 2.8 billion tons of platinum, 30 billion tons of iron ore, and 13 million tons of gold deposits spread over five regions. Zimbabwe also has resources of copper, nickel, chromite, and methane gas.