It’s widely believed that “illegal” mining is only undertaken by small groups of entrepreneurs or artisanal operators. If, and when, the state cracks down on their operations, the culprits are removed (sometimes with considerable violence, as in Brazil and Indonesia) to be replaced by registered and “more responsible” companies. But the reality is often more complex, and the offenders more numerous and difficult to identify. In the recent past, major corporations, such as Anglo American and Rio Tinto, have not been above collaborating with smallscale miners, using them as a point of entry into untapped deposits. More benignly, some others (Barrick-Placer in Venezuela, Benguet in the Philippines) have allowed smallscale miners to occupy their diggings, pending takeover of the worked areas. Even where government and company severely frown on such tie-ups, they may turn an unseeing eye on illegal operations in return for payoffs. (This is something alleged in the case of Freeport-McMoran’s massive Grasberg mine in West Papua).
See http://www.minesandcommunities.org/article.php?a=9870.