London is expected to start Tuesday on a firm footing with traders predicting the Footsie will open around 10 points higher.Mining stocks are in focus this morning with BHP Billiton and Kazakhmys both making announcements.Mining giant BHP Billiton has successfully persuaded several of its iron ore customers in Asia to move to shorter term contracts. The renegotiated contracts cover the majority of BHP Billiton's iron ore sales volume.Heavy write-downs meant lower full year profits at copper miner Kazazhmys despite a much stronger second half as the price of the metal rebounded. Copper prices hit a new 11-week high this week, but were weak at the start of the year and Kazakhmys's underlying profits for 2009 fell to $1.02bn from $1.14bn.South Africa-focused bank Investec has agreed to pay £412m for the sharesin British wealth manager Rensburg Sheppards that it does not already own.Pizza delivery firm Domino's Pizza continues to knock spots off its 2008 sales performance, with the company reporting a 10.5% rise in like-for-like sales for the year to date. The group said it has had a strong start to 2010, despite the adverse weather conditions in the early part of the year.The net asset value per share of Rugby Estates Investment Trust rose by just under a quarter in 2009, putting its portfolio performance in fourth place in a peer group of 268 funds.