ArcelorMittal SA, the South African unit of the world's No. 1 steel maker, has acquired a 16.3 percent stake in Coal of Africa Ltd. (CoAL) for 404.5 million rand ($44.98 million) in cash.

ArcelorMittal South Africa, the largest steel producer in Africa, said in a statement the purchase would help it secure its future coal needs, a key steel-making ingredient, mitigating one of the company's key variable input costs by acquiring the coal locally.

CoAL is involved in exploration and development of thermal and metallurgical coal projects in South Africa.

Shares in CoAL jumped 5.5 percent on the news, and traded 3.1 percent higher at 6.55 rand by 1001 GMT, while ArcelorMittal South Africa's shares declined 4.12 percent to 79.13 rand, while the Top-40 index .JTOPI lost 1.86 percent.

As part of the transaction, ArcelorMittal South Africa has an option to enter into an off-take agreement with CoAL for the supply of 2.5 million tonnes of metallurgical (coking) coal annually, the company said.

ArcelorMittal South Africa last year purchased 5.2 million tonnes of coal, which makes it one of the largest input raw materials for the company.

The 16.3 percent stake makes ArcelorMittal South Africa CoAL's second largest shareholder after the 17.3 percent owned by Africa Management Limited, a company owned by black investors associated with the Mvelaphanda Group.

The price paid for the stake was based on the previous 15-day volume weighted average share price of CoAL on the Johannesburg Securites Exchange.

(Reporting by James Macharia)

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