The Harvard Corporation has sold about $3 million worth of stock in AMAX, Inc., a U.S. multinational mining corporation that owns one-third of a mining company employing more African labor in Namibia than any other firm.

Top managers of Harvard's investment portfolio said yesterday the approximately 60,000 shares of AMAX stock were sold on the stock exchange on September 13 and 14 for strictly financial reasons.

Students had expressed oppostion to Harvard's ownership of AMAX stock because the firm's Namibian operation violates a 1971 International Court of Justice ruling prohibiting foreign investment in Namibia.

Namibia is a nation in southwest Africa that is occupied by South African troops and run by South African administrators, despite United Nations resolutions forbidding such control.

Harvard sold the AMAX stock when its value increased dramatically because Standard Oil of California was trying to buy out AMAX, Henry J. Ameral, assistant treasurer of Harvard College, said this week. Harvard also owns about $24 million worth of stock in Standard Oil of California.

Standard Oil has unsuccessfully ended its attempt to increase its holdings in AMAX stock, Donald Maytum, secretary to Standard Oil of California Corporation, said yesterday.

The price of the AMAX stock has dropped from a high of about $52 per share--the price at which Harvard sold its stock--to about $49 per share since Standard Oil abandoned its effort to buy out AMAX.

"We did make an offer to AMAX on September 4 for a possible merger of the two corporations on specific terms. They (AMAX) rejected it. As far as we're concerned, it's all over," Maytum said.

Harvard bought most of the AMAX stock in the summer of 1975.

The AMAX stock was "sold to make a profit and we did," Ameral said.

The political climate in Namibia "wasn't something we considered in making such a decision," he added.

Ameral said Harvard sold the AMAX stock at about $52 a share. Standard Oil executives had said earlier this month they would buy the stock at $57 a share if their merger plans went through.

AMAX owns one-third of Tsumeb Corporation. Since its formation after World War II, Tsumeb has contributed more than $150 million in tax revenues to South Africa's colonial administration in Namibia.