AMM’s silicomanganese price increased to 52 to 54 cents per pound Dec. 5 from 51 to 53 cents previously.

"It seems that the silicomanganese market is getting very exciting. Other tenders that have been decided have been (done so) at above current market prices, and we booked some business ourselves around the 53- to 54-cent-(per-pound) levels for first quarter," one trader said.

While Letart, W.Va.-based Felman's idled plant in New Haven, W.Va., has had a more immediate impact, South African power issues could crimp supply in early 2014, sources said.

"The issue with Eskom (Holdings SOC Ltd.) is more serious than they've been telling the market. There's a buyback program in place and they're quietly asking some producers to extend it," the first trader said.

But one consumer, who said he completed some 2014 silicomanganese business recently at a firm number below current market prices, disagreed that there was a supply crimp. "We've been offered ample tons," he said.