Montreal, Canada

Investors venturing into foreign mining companies must be vigilant in mid-2011. Increasingly, more governments are proposing to get a slice of the mining pie as corporate profits boom.

As markets continue higher for things like copper, gold, nickel, lead, zinc and other metals, more countries are violating contractual agreements and rewriting terms for foreigner investors.

Peru joins Tanzania, Chile, Australia and several others attacking mining company profits in the name of socialism amid a tremendous bull market in commodities since 2002.

On Wednesday, Tanzania joined Brazil this week debating a “super-profit tax” on miners to pay for local development programs. You’ve got to wonder if some or all of this potential “super-profit tax” money will go to the poor, unsuspecting population or to local officials’ foreign bank accounts. I’m sure most funds will go to the latter.

African Barrick Gold (London-ABG) has seen its stock prices crater over the past year since breaking from her parent, Barrick Gold (NYSE-ABX). This week’s news adds more fuel to the fire already emblazing African Barrick in Tanzania.

In Peru, the election of socialist Ollanta Humala threw the Peruvian bourse into a tailspin with stocks in Lima plunging almost 10% on Tuesday.

Humala would ideally like to nationalize or partially nationalize mining interests in the country to help pay for social programs. That’s not the sort of news investors like to hear.

Foreign investors returned to Lima on Wednesday after the new president-elect suggested he might impose a levy or a special mining tax instead.

Minas Buenaventura SA (NYSE-BVN) is one of the largest gold-mining companies in Peru. The stock crashed more than 13% on Tuesday and still can’t find a footing; investors are leaving.

Increasingly, more countries, including major economies like Australia, are digging a dagger deep into mining companies to extract a financial premium or confiscate assets. The rules don’t apply and investors must fend for themselves. I’m sticking to mostly American, Canadian and a few Australian mining companies; though not a guarantee, companies operating in these countries have more financial and political muscle… at least for now.