London afternoon: Gains trimmed

London saw its gains pared over the lunch time session in predictably quiet trading. Around one-third of Footsie constituents are now in the red, compared to around one-fifth at midday.Included among the laggards is Cairn Energy, which gives back some of the chunky gains racked up over the first two days of the week after the oil company said it would start drilling operations in Greenland a week ahead of expectations.Also on the slide are defensive stocks such as utilities United Utilities, Severn Trent and International Power.Mining giant Rio Tinto has accepted a $2.025bn offer for its Alcan Packaging pharmaceutical, tobacco and food divisions from the packaging group Amcor as it continues its programme of asset sales to ease its debt pile.Also in mining, Minera Penmont, the joint venture 56% owned by silver miner Fresnillo, has made a bid to snatch Canadian mining company Canplats Resources from bullion producer Goldcorp.Minera is offering C$4.20 in cash plus one share, with a notional value of C$0.20, in a new exploration company for every Canplats share. The offer terms trump those offer by Goldcorp, the world's second largest bullion producer. Goldcorp launched an offer in November worth C$238m. Elsewhere in the sector ENRC, Kazakhmys, Vedanta and Xstrata all enjoy support.British Gas owner Centrica has agreed to sell a 50% equity stake in its 270 megawatt Lincs offshore wind farm for £50m in cash.Tullow Oil has firmed its view on the potential of the West Cape Three Points block, offshore Ghana, after it latest test drill. The Mahogany Deep-2 well, drilled 3 km from Mahogany-3, was the furthest down-dip Jubilee well in the West Cape Three Points licence, Tullow said.Premier Oil has plugged and abandoned the Cá R?ng Vang well on Block 07/03, offshore Vietnam. The oil firm had better luck in Pakistan, where the Kadanwari-19 well, operated by Italian oil giant ENI, encountered 12m of high quality net gas pay in a Lower Guru Sandstone reservoir.Support services contracting firm Balfour Beatty has won a facilities management contract from defence technology outfit QinetiQ. The seven year contract has a base-line value of £15m per annum, and will be supplemented with additional fees for non-core services.A bid battle could still be on the cards for care home group Supporta after its main shareholder suggested it should consider a possible cash offer from a third party rather than an agreed all-share deal with Mears.One takeover that does look done and dusted is the takeover of live music group MAMA by CD and DVD retailer HMV. The two companies have agreed on an acquisition worth £46m or 5.4p a share. Finance consultancy SMS Finance recently made a 4.75p a share offer for MAMA.Africa-focused diamond producer Pangea DiamondFields has completed an upgrade of processing facilities at its Cassanguidi project in Angola but lowered its production targets. It now expects to produce 6,000 carats a month in the first quarter of 2010, compared with a previous estimate of 8,000 tonnes.Shares in digital terrestrial television technology company Motive Television slumped after the company said the sale of its remaining production assets is taking longer than expected, and now won't be completed until the new year.