Zimplats Holdings (ASX:ZIM) reported mined volume of 2 million tonnes in the September quarter, a 1% decrease from the previous quarter, primarily due to slightly lower open-pit volumes in line with pit design, according to a Thursday filing with the Australian bourse.

Ores mined during the reported quarter were in line with the same period last year.

The 6E head grade for the quarter was 3.3 grams per tonne, slightly lower than the 3.38 grams per tonne in the same quarter a year ago, the filing said.

Ores milled were stable at 2 million tonnes compared with the September quarter last year, the filing added.

The total operating cash costs increased 21% to $162.9 million from $135 million year on year, driven by salary adjustments, mill relines at two concentrator plants, and the planned replacement of conveyor belts, per the filing.

The company's shares rose past 2% in recent Thursday trade.