Concerns about falling demand hit mining stocks on Monday with heavyweight producers in London providing a drag on the sector.Copper prices continued to decline today on rising inventories and short-lived optimism surrounding the bailout deal in Cyprus.Last week, the London Metal Exchange announced that copper inventories were at a 10-year high, rising a whopping 165% since October on the back of increasing production and slower purchases from China. Meanwhile, it was also revealed last week that coking coal imports in China dropped 24.5% month-on-month in February.A trader from Chicago told Sharecast that copper prices are not following - "as a matter of fact, going in the total opposite direction to" - the rally in stock markets."China is a big concern and everybody believes things are worse than they appear. Price action is bearish (oversold conditions) and everybody is waiting for the US economy to pick up," he said.Meanwhile, gold prices slipped under $1,600 for the first time in over a week as the dollar strengthened against the euro despite the deal to save Cyprus from financial collapse. Gold for April delivery was down nearly 0.9% at $1,592.30 an ounce.The initial enthusiasm surrounding the Cyprus bailout proved short-lived today with the single currency quickly erasing gains against the greenback as markets digested what the aid package means for the future of the Eurozone.Eurasian Natural Resources Corporation, known as ENRC, was the heaviest faller on the FTSE 100 on Monday, a day ahead of full-year results from part-owner Kazakhmys. Kazakhmys, which has a 26% stake in ENRC, is expected to announce a substantial write-down of its value in its fellow Kazakh miner.ENRC was down 6.31% on the day at 267.31p before the close and us now trading at levels not seen since late 2008.Sector peers EVRAZ, Vedanta and Antofagasta were also registering heavy losses today.Top performing sectors so far todayTechnology Hardware & Equipment 1,105.97 +2.45%Mobile Telecommunications 4,382.11 +2.17%Electronic & Electrical Equipment 4,234.36 +1.28%Forestry & Paper 9,554.19 +1.08%Fixed Line Telecommunications 3,280.71 +1.06%Bottom performing sectors so far todayIndustrial Metals & Mining 2,181.13 -3.21%General Retailers 2,128.49 -1.05%Mining 17,740.31 -1.03%Life Insurance 5,699.01 -1.00%Oil Equipment, Services & Distribution 23,940.69 -0.89%BC