Profits at copper miner Antofagasta sank more than expected in 2014 as lower production and weaker commodity prices were met with higher costs, prompting the company to slash its dividend by 77.4%.The company did not address recent rumours that it may have to close its flagship Los Pelambres project in Chile.However, it did say that there is "some inherent uncertainty" surrounding the project after a recent court ruling to destroy part of its tailings dam.Antofagasta said earnings before interest, tax, depreciation and amortisation (EBITDA) dropped 17.8% to $2.22bn, missing the market forecast of around $2.3bn.Revenues declined 11.4% to $5.29bn as realised copper prices dropped 8.5%.Copper output fell 2.3% to 704,800 tonnes, as previously indicated, while gold production fell 7.8% to 270,900 ounces and molybdenum volumes eased 12.2% to 7,900 tonnes.At the same time, cast costs before by-product credits were up 2.2% over the prior year at $1.83 a pound as a weaker peso and lower input costs were offset by the one-off signing of bonuses after labour contract renegotiations.However, Antofagasta last month guided to lower cash costs of $1.75 in 2015, driven by more favourable input costs, a weaker peso and lower oil prices.The group declared a final dividend of 9.8 cents, taking the full-year payout to just 21.5 cents, compared with 95 cents in 2013.As for Los Pelambres, Antofagasta is planning to appeal the court's decision that it must demolish part, or all, of its tailings dam wall due to its alleged impact on the flow of a nearby river to local communities."However, the adverse ruling from the Civil Court of Los Vilos, means that there is some inherent uncertainty as to the potential impact on Los Pelambres for the rest of 2015 and beyond," the group said.Earlier this month, management resolved a two-week-long protest with locals seeking action to help alleviate current drought conditions, though the action did result in 8,000 tonnes of lost copper production.