July 20 (Reuters) - Britain's FTSE 100 index is seen opening up 13 points on Thursday, according to financial bookmakers. * BHP BILLITON: Chilean authorities have approved a $2.5 billion expansion of BHP Billiton's Spence copper mine, a local newspaper reported on Wednesday, though the company has not yet decided whether to go ahead with the project. * CARILLION: Oxfordshire County Council, which last week ended much of a 10-year 500 million pound ($652 million) contract with Carillion, is now debating the future of a facilities management deal with the crisis-hit British construction firm. * EX-DIVS: No FTSE 100 companies will go ex-dividend on Thursday, although several mid-caps will go ex-div, after which investors will no longer qualify for the latest dividend payout. * BREXIT: Barely more than one in 10 British companies has started to put Brexit contingency plans into effect as many firms remain unclear about what leaving the European Union will mean, a leading business organisation said on Thursday. * OIL: Oil prices held steady on Thursday following solid gains the previous day when falling U.S. fuel inventories lifted the market. * The UK blue chip index FTSE 100 gained 0.6 percent and closed at 7,430.91 points on Wednesday, helped by a buoyant consumer goods sector after Reckitt Benckiser sold its food business, while housebuilders added to gains. * For more on the factors affecting European stocks, please click on: cpurl://apps.cp./cms/?pageId=livemarkets * UK CORPORATE DIARY: Moneysupermarket.Com Half Year 2017 Earnings Release Howden Joinery Group Half Year 2016 Earnings Release Nichols PLC Half Year 2017 Earnings Release Sports Direct International Full Year 2016 Earnings Release Unilever PLC Q2 2017 Earnings Release Anglo American Trading announcement Premier Foods Trading announcement SSE Trading announcement TODAY'S UK PAPERS > Financial Times > Other business headlines Multimedia versions of Reuters Top News are now available for: * 3000 Xtra : visit http://topnews.session.rservices.com * For Top News : http://topnews.reuters.com (Reporting by Siju Varghese; Editing by Sunil Nair)