THE De Beers black empowerment deal involving the high-grade Marsfontein mine in the Northern Province is undervalued by half, it was reported on Friday. It was announced last Friday that a 24% share of the mine will soon be held by black companies. De Beers is selling 49% of its 60% in Marsfontein for R200-million — the other 40% is held by Canadian-listed Southern Era Resources. But Business Report suggested on Friday that the De Beers assessment of the kimberlite deposit being mined covers only the probable value of the deposit to a depth of 100m. The deposit is probably viable to 160m, the newspaper said. It is likely that there are other viable deposits on the same farm.