UPDATE 2-Gold Fields says losing 20 kg a day at shut shaft

(Adds lost output, updates share price)

By James Macharia

JOHANNESBURG, June 26 (Reuters) - Gold Fields Ltd (GFIJ.J) said on Thursday it had lost 20 kg of gold after shutting one shaft at its Kloof mine in South Africa to allow investigations to take place after two miners were killed following a tremor.

The employees were killed in a fall of ground at Kloof's No.4 Shaft early on Thursday while cleaning some 3 km (1.8 miles) below the surface. No other injuries were reported.

The tremor rated 1.2 magnitude on the Richter scale.

"All production at the shaft has been stopped and an investigation by the Department of Minerals and Energy (DME) is being carried out," Gold Fields said in a statement.

"We have lost 20 kg (706 ounces) of gold after closing the shaft, and we could continue to lose the same amount per day if it remained shut," Gold Fields spokesman Andrew Davidson said.

The shut shaft is one five at the key Kloof mine, which produces a total of 95 kg of gold a day, he added.

The DME had issued an order to shut the shaft and take remedial action before the shaft could re-open, Davidson said.