(Adds quotes, smelter plans)
By MacDonald Dzirutwe
HARARE, Aug 19 (Reuters) - Anglo American (LONDON:AAL) Platinum's AMSJ.J Zimbabwe unit Unki said on Wednesday it was considering either building a new smelter or expanding facilities at larger rival Zimplats ZIM.ZI .
President Robert Mugabe's government last week suspended a 15 percent tax on raw platinum exports after mining companies committed to building smelters and refineries.
"These efforts are part of the solution agreed with the government which have resulted in the suspension of the 15 percent tax," Colin Chibafa, Unki Mines chief financial officer said in emailed responses to questions from Reuters.
Unki is the smallest of three platinum mines in Zimbabwe and has previously said it would take two years to build a smelter.
Mines in Zimbabwe send platinum group metal concentrates for refining to South Africa but the government wants the process to be done locally to increase the value of mineral exports.
Platinum was the largest mineral export in Zimbabwe last year, and the southern African nation holds the world's second-largest reserves of platinum which can be used in catalytic convertors or for making jewellery.
Chibafa said the company was considering "a green fields smelter at Unki using some of the equipment that Anglo American Platinum Limited has available."
The equipment was initially set for constructing other furnace projects at Amplats mines in South Africa, he said.
Chibafa said Unki was also looking at the possibility of expanding the smelter facilities at rival Zimplats, Zimbabwe's largest platinum mine, which is majority-owned by Impala Platinum Holdings IMPJ.J .
The second plan would also see the Zimplats smelter processing platinum from Mimosa Mines, a 50-50 joint venture between Implats and Aquarius Platinum Ltd AQP.L .
Zimplats' officials were not available to comment.
Unki was likely to finalise the cost for both options by the end of October, Chibafa said.
The company said a plan to upgrade two furnaces owned by two ferrochrome producers in Zimbabwe for smelting PGMs was discarded because it was costly.
Unki's platinum output rose 6 percent to 32,000 ounces in the half-year to June, from the previous year.
The company resumed exports last month after suspending them on April 10, following the introduction of the platinum tax. (Editing by James Macharia and Keith Weir)