South Africa is one of the richest countries in natural resources - from gold to iron ore. The problem: few companies want the headache of digging it up. Strikes, unreliable power supply, a mining code that has been under review for six years and disputes over compulsory holdings for local black shareholders have dented investor confidence, the Mining Indaba in Cape Town was told this week.Companies are voting with their feet: BHP Billiton, the world's biggest miner, left last year, leaving only five of the world's 40 largest commodity producers with operations in South Africa.Investors "want certainty, they want a clear regulatory environment, and they want an environment [in which] companies are not held hostage by unreasonable demands and unreasonable cost escalations," said Neal Froneman, Sibanye Gold CEO, the biggest producer of bullion in South Africa."They can't operate or invest in the current environment."Sibanye was spun out of Gold Fields three years ago, when the latter wanted to reduce its presence in the country.South Africa has the world's biggest reserves of platinum and third-largest of gold; it is Africa's largest source of iron ore and coal. Yet its influence is declining.The local mining industry makes up just 4.4% of global mining stocks, down from 18% in 2000 and 47% in 1980, according to Jim Rutherford, non-executive director of Anglo American.Though part of the deterioration is a result of the global slump in metal prices threatening 32000 jobs in the country, some of the problems are self-inflicted.One is an argument over a requirement that black investors need to own at least 26% of every company's assets or equity - adopted to help redress economic imbalances created by apartheid."When you do that you're not going to get the overseas investors," said Andrew Mitchell, a partner at Fasken Martineau in Johannesburg."You need a rich resource to sustain that and there are not many at the moment."The lack of availability of electricity has also undermined production and strikes are a further problem, with the platinum stoppage of 2014 lasting five turbulent months. ..