NEW YORK ( TheStreet) -- Great Northern Iron Ore Properties ( GNI) emerged the sole gainer last week, rising a marginal 1.1%. Among the laggards, Stillwater Mining ( SWC), Alpha Natural Resources ( ANR) and Mechel ( MTL) lost substantial ground.Stillwater Mining slumped 34.6% as silver prices plummeted 27.4% to $31.14 per ounce at close last week. Meanwhile, Mechel and North American Palladium ( PAL) shed 28.6% and 21.5%, respectively. Alpha Natural Resources plunged 31.5% after Dahlman Rose, Citigroup and Deutsche Bank initiated price cuts on the stock last week. Additionally, Alpha has lowered its shipment guidance range to 102.5 million to 109.5 million tons from the previous view of 104 million tons to 112 million tons, citing lower production and reduced exports from Asia. Also, a reversal in metallurgical coal prices would pressurize coal company stocks. Industry analysts say prices for met coal may dip further indicating a downfall for stocks also. Among others, Patriot Coal ( PCX) shed 27% on concerns regarding met coal prices. Early last week, the company announced that geological issues at its two longwall mines and the closure of a thermal mine are likely to affect 2011 third-quarter production and result in 450,000 tons loss during the quarter. James River Coal ( JRCC) and Cliffs Natural Resources ( CLF) were the other losers last week, wiping out 26.9% and 25.8%, respectively. With gold prices declining 6.8% to $1,656.8 per ounce at close last week, gold stocks Brigus Gold ( BRD) and US Gold ( UXG) relinquished 26.9% and 24.6%, respectively. Freeport-McMoRan Copper & Gold ( FCX) slumped 22.2% last week. Workers at the company's gold and copper mines in Eastern Indonesia began their month-long strike to protest against low wages, bringing production and shipments to a halt. Also, Jefferies has cut its price target on FCX by $10 stating the ongoing strike could impact the company's near term results. Walter Energy ( WLT) eroded 21.5% after revising its sales outlook lower for the second half of 2011. Walter now estimates to sell about 5.2 million metric tons of coal versus its earlier guidance of 5.9 million metric tons, citing output slowdown at its mines in Alabama and British Columbia. Other laggards were Hecla Mining ( HL) and Allegheny Technologies ( ATI), down 21.2% and 21%, respectively. Aluminum Corp. of China ( ACH) erased 20.6% on renewed global economic fears and declining commodity prices.