06:57 AM EDT, 05/25/2018 (MT Newswires) -- Shares of gold miner Centamin (CEY.L) traded sharply lower early Friday after the firm chopped its production forecast for the second quarter while raising the cost guidance at its flagship Sukari mine in Egypt.

The company, which is also listed on the Toronto Stock Exchange, said in an update that underground production had come in 10% below forecast, with production equipment availability issues resulting in lower output ore tonnage mined. It noted that the development grade had also been "lower" than budgeted.

Following persistently lower grades, Centamin said the 2018 guidance for Sukari, the first large-scale modern gold mine in Egypt, had been cut to between 505,000 and 515,000 ounces, at a cash cost of production of $625 to $640 per ounce produced and an all-in-sustaining cost of $875 to $890 per ounces sold.

That deterioration in outlook has come about in less than a month as the company said on May 3, as part of its forecast in the first-quarter results, that it was maintaining a full-year guidance for 2018 of 580,000 ounces at forecast cash cost of production of $555 per ounce and all-in sustaining costs of $770 per ounce sold.

Centamin added, however, that "grades from the open pit are forecast to increase" in the third quarter to a level noted within its first-quarter results, as production equipment availability was now improving and the processing plant was performing in line with expectations, throughput, and productivity.

The company is scheduled to publish its preliminary production results for the second quarter on July 9.

Shares slumped more than 16% in London, the second-worst performing in the FTSE 250 Index at the time of writing.

Price: 135.05, Change: -24.30, Percent Change: -15.25