Switzerland's Glencore International, the mining and commodities trading giant, said on Thursday first half net income jumped 42%, spurred by a sharp rise in metal prices.

Revenues leapt more than 50%t to $70 billion thanks to a threefold increase in industrial activities, with a slight rise in the contribution from trading.

The privately-held Glencore, which is preparing for a future as a listed company after issuing a $2.2 billion convertible bond last year, earned $1.563 billion  excluding exceptional items for the period, compared to $1.097 billion in the year earlier period.

Glencore, the largest shareholder in mining giant Xstrata, said earnings before interest, tax, depreciation and amortisation (EBITDA), rose to $2.630 billion from $1.554 billion in the same period in 2009, when commodities prices were weighed down by the effects of the financial crisis.

EBITDA is a key metric for heavily indebted companies like Glencore, as it is used to assess their ability to service their borrowing. The company's net debt rose to $13.6 billion from $10.2 billion, while debt coverage was largely unchanged due to increased earnings and operating cashflow, the company said.

The Glencore results rounded off a solid first half for mining companies, which have been helped by a rebound in the price of industrial metals such as aluminium and copper, with averages first half prices of the latter up 76% compared with 2009.

Other miners to report strong numbers recently include Potash suitor BHP Billiton, which on Wednesday posted its best half-year earnings in two years, and Rio Tinto, which reported record profit earlier this month.