(Adds detail, background)

RABAT, Sept 22 (Reuters) - Morocco's biggest mining company Managem posted a 63 percent drop in first-half net profit to 52 million dirhams ($5.35 million) on Thursday, citing weak global commodities prices.

Managem said it was hit by a 12 percent slide in silver prices, a 21 percent drop in both copper and cobalt and a 16 percent decline in zinc during the first six months of 2016.

Controlled by the Moroccan royal family's holding company SNI, Managem produces gold, silver, cobalt and copper in Morocco and Gabon and had won contracts to search for gold in two mineral-rich areas of Sudan.

The company said it has discovered an additional silver deposit of 240 tonnes in Imider, sufficient for an extra year of extraction, as well as a further 2.5 million tonnes of copper and 2,507 tonnes of cobalt in its Bou-Azzer mines.

Consolidated sales were down 12 percent year on year to 2.01 billion dirhams, with the decline capped by increased production, the company said.

Managem has ended gold extraction in its southern Akka mines after reserves fell to non-viable levels, leading to the loss of about 300 jobs.

The company said it will focus on copper after the discovery two years ago of a deposit of about 1.15 million tonnes in the same area, increasing total copper reserves to 8 million tonnes.

Copper production was up 28 percent in the first half, it said. ($1 = 9.7273 Moroccan dirham)

(Reporting by Aziz El Yaakoubi; Editing by David Goodman) ((aziz.elyaakoubi@thomsonreuters.com; +212623934595)(;))