MDI is a relatively illiquid stock, but if you're patient it may be worth your time looking into the business. Their continued rig expansion, geographically diversified USD based earnings, the financial difficulties experienced by one of their main competitors (
http://www.bdlive.co.za/business/mining/2015/01/13/missed-loan-deepens-shaft-sinkers-woes) etc. make for enticing prospects. It appears as if these chaps are capable of delivering large capex savings to the mining houses; couple that with the move to mechanisation and it should bode well.