Impala Platinum has become the latest platinum group metals (PGM) producer to advise of sharply higher earnings as producers benefit from soaring metals prices.Headline earnings and HEPS for the year to end-June are expected to increase to between R21.8bn and R23.8bn, or 2,429c to 2,652c, respectively, Implats said in a statement on Wednesday. A year ago, headline earnings and HEPS were R0.7bn and 82c, respectively.The group said earnings increased primarily due to gains in both precious and base metal pricing, which resulted in a 51% improvement in achieved revenue per 6E ounce sold. (6E production refers to the combined output of six precious metal elements: platinum, palladium, rhodium, ruthenium, iridium and gold.)Group 6E refined and saleable production improved by 5% to 3.56-million ounces as excess in-process inventory was reduced during the period.The benefit of improved revenue was partially offset by the 8% increase in stock-adjusted group unit costs to R24.249/oz, the higher cost of metals purchased by Impala Refining Services and increased tax and royalty payments. Group earnings before interest, tax, depreciation and amortisation (ebitda) increased to about R43.6bn, while free cash generated improved to R22bn, it said.The free cash flow for the period was adversely impacted by the classification of a portion of Zimplats local currency cash balances to statutory receivables.Basic earnings for the period benefited from the reversal of impairments of R8.1bn, equivalent to 904c per share (post-tax), relating to property plant and equipment and the prepaid royalty at Impala Rustenburg due to higher prevailing rand PGM pricing.Last month Implats reported higher annual refined platinum production and sales amid significantly improved rand PGM pricing and as its mining and processing assets delivered a strong operating performance.Sales revenue in the year to end-June surged as dollar prices climbed and operational performance strengthened across its mines.The group benefited from significant, broad-based appreciation of dollar pricing for both precious and base metals in the period. The stronger rand provided only a marginal offset to achieved pricing and sales revenue rose by more than 50% to about R38,100 per 6E ounce sold as a result.Group 6E production improved marginally to 3.5-million ounces from 3.48-million ounces a year ago, the group said in an operating update. Production from managed operations increased by 1% to 2.75-million ounces.Refined 6E production, which includes saleable ounces from Impala Rustenburg North Shafts and Impala Canada, improved by 5% to 3.56-million ounces.Implats will release its annual results on September 3.Business Day