An increase in copper stockpiles on Monday pushed down prices of the metal used in power and construction, while lead continued to rise from nine-month lows on fears of tight supply.

LEAD: Benchmark lead on the London Metal Exchange closed 1.7 per cent higher at $US2,385 a tonne. It has risen almost seven per cent since on May 2, touching $US2,241, the lowest since August.

TIGHTEST MARKET: ‘Lead from a raw materials side is probably the tightest commodity market out there. There has been a big clamp down on Chinese private sector mining. China is around 60 per cent of primary lead supply,’ BMO Capital Markets analyst Colin Hamilton said.

PRICE OUTLOOK: Prices were likely to hit $US2,640 in the third quarter, Hamilton said.

SUPPLY: Over 2014-2016 global mined lead supply shrank by roughly 500,000 tonnes, or 10 per cent. A Chinese crackdown since last year on industries that are heavy polluters squeezed output further.

This year, consultancy Wood Mackenzie forecast a market deficit of 115,000 tonnes in 2018 and 56,000 tonnes in 2019 after a 119,000 shortfall last year.

LEAD STOCKS: Headline stocks in LME-registered warehouses have fallen by a third since the start of last year to 131,225 tonnes.

LEAD TIME SPREAD: However a rise in the discount of cash lead over three-month metal to $US13 a tonne, the highest since November, suggests there is no immediate shortage of metal.

COPPER: LME copper shed 0.8 per cent to finish at $US6,885 a tonne after headline stocks in LME warehouses rose 8,900 tonnes to 289,975 tonnes.

Inventories had fallen more than 100,000 tonnes since March to just over 280,000 tonnes, while copper prices have moved sideways after reaching a four-year high of $US7,312.50 in December.

COPPER SCRAP: The effect of Chinese curbs on scrap metal imports introduced this year will be blunted by a rise in domestic scrap production, Wood Mackenzie consultants Yanting Zhou and Sifang Liu said.

‘Total scrap supply in China will drop by around 100,000 tonnes in 2018, but will return to positive growth in 2019, to rise by approximately 70,000 tonnes,’ they said in a note. Copper prices rose sharply last year when the restrictions were announced.

COPPER TECHNICALS: Copper may be forming a head and shoulder formation with a neckline at $US6,532/$US6,507, said Stephanie Aymes, head of technical analysis at Societe Generale.

‘A decisive break below would lead to a deeper correction towards $US6,366/30 and $US6,204/$6,168,’ she said in a note.

OTHER METALS: Nickel shot up 3.2 per cent to end at $US14,500 a tonne, aluminium rose 1.3 per cent to close at $US2,318.50 a tonne, zinc lost one per cent to $US3,055 a tonne and tin dipped 0.2 per cent to $US20,950 a tonne.