LONDON—Glencore PLC is reshuffling the board of one of its giant African copper operations following an internal review that the company said found weaknesses in its controls over financial reporting.

The move comes amid an investigation by Canada’s Ontario Securities Commission, or OSC, the country’s biggest regional securities regulator, into the governance practices of the Glencore copper subsidiary, Katanga Mining, which is based in the Democratic Republic of Congo. Investigators are probing financial statements and disclosures...