Two mine workers in South Africa were killed on May 12 as they reported for work at Lonmin’s platinum mine where a strike as stretched into its fourth month.

Reuters reported that Lonmin chief executive Ben Magara confirmed one employee was killed in what he called a "a very sad incident," but provided no other details on a conference call with reporters.

London-listed Lonmin, the smallest of the three platinum firms hit by the costliest strike in South African mining history, saw its underlying earnings before interest and tax shrink by almost two thirds in the six months to the end of March.

Workers have slowly been returning to the Marikana Mine, 120 km (70 miles) northwest of Johannesburg, in recent weeks with attendance reaching 12 percent.

Lonmin was hoping more miners would start returning after it made its wage offer directly to employees, sidestepping the majority Association of Mineworkers and Construction Union (AMCU) in a bid to end a four-month strike.

Lonmin's larger rivals, Anglo American Platinum and Impala Platinum, have also presented wage offers directly to employees after talks with the AMCU collapsed.

AMCU's leaders maintain that most of their roughly 70,000 striking members are not happy with the latest offer.

The companies are offering increases of up to 10 percent that they say would raise the overall minimum pay package to 12,500 rand ($1,200) a month by July 2017, including cash allowances such as for housing.

AMCU had initially demanded an immediate increase to 12,500 rand in the basic wage, excluding allowances, but softened that in March to staggered increases that would amount to 12,500 rand within three or four years - still a third more than what the companies are offering in basic salaries.

The strike is the longest and costliest to hit South Africa's mines, highlighting the discontent among black miners who feel they are still not reaping the benefits of the country's mineral wealth two decades after apartheid ended.