The company's also recorded a 36% decrease in manganese and ferromanganese ore sold from its Bootu Creek and Tshipi Bowra mines.
Total ore sold for the six-month period was 838,313 tonnes of manganese and 18,695t of alloy.
In addition to market conditions, OM Holdings said: "Administration and other operating costs increased to $19.2 million from $16.4 million due to the higher depreciation and amortisation expenses from our Australian subsidiary as it made its move from contract miner to an owner operator model."
It also said further costs were incurred by the company's Sarawak subsidiary when production began in 2014's third quarter.
Cash reserves as of June 30 were at $56.1 million, with the company's loss per share increasing to $A0.043.