The commodity cycle peaked in 2011. But the damage is only now catching up with commodity firms, spurred by worries that China’s economy is in a slump. At the benign end of the spectrum Alcoa, an American aluminium bellwether since 1888, is breaking itself up. It hopes that its manufacturing business will be re-rated by investors once separated from its more cyclical mining and smelting arm. Other commodity firms are now locked in a more brutal battle for survival. Yesterday the shares of Glencore, an Anglo-Swiss trading and mining giant, collapsed by 30% to a record low and its bond spreads soared as investors panicked about its $50 billion gross debt. Worldwide, listed mining and metals firms have amassed a $1 trillion debt mountain; $500 billion of that sits with firms making losses. Many companies have no serious chance of digging themselves out of their holes.