NEW YORK ( TheStreet) -- Harmony Gold Mining ( HMY), James River Coal ( JRCC) and Aluminum Corporation of China ( ACH) rallied higher last week.

But Metalline Mining ( MMG), Stillwater Mining ( SWC) and Cliffs Natural Resources ( CLF) saw declines.

Leading the advancers' list, Harmony Gold Mining gained 3.1% last week after the company discovered superior grade gold at its 50% owned Wafi-Golpu mine in Papua New Guinea.

Meanwhile, James River Coal advanced 2.9%. The company plans to acquire West Virginia-based coal producer International Resource Partners in order to expand its access to metallurgical coal.

James River Coal will pay $475 million for International Resource Partners, which operates nine coal mines and has 136 million tons of coal reserves and resources.

Aluminum Corporation of China and Great Northern Iron Ore Properties ( GNI) rose 1.1% and 0.7%, respectively, last week.

Meanwhile, steel producer and metals recycler Steel Dynamics ( STLD) edged up 0.4% during the week.

Steel Dynamics last week said it was raising its quarterly dividend by 33% to 10 cents per share, with a dividend yield of 2.2%. It also raised its first-quarter guidance for earnings per share to a range of 37 cents to 42 cents.

The company added that demand for sheet and special bar quality steels in the U.S. market remains robust.

Other metals and mining stocks recorded significant losses, however. Metalline Mining led the losers' pack and plummeted 17.9%.

Stillwater Mining lost 14.1% last week. The company reported 2010 net income of $50.4 million, or 51 cents per share, compared with a net loss of $8.7 million in 2009. Revenue increased 40.9% to $555.9 million for the year.

Cliffs Natural Resources declined 11.5% during the past week. The company expects iron ore prices to remain higher in the near term, primarily due to strong demand from China coupled with lack of new production capacity. Coal producer Patriot Coal ( PCX) fell 11.3%.

Hecla Mining ( HL) slumped 11.1%.

Among others, Penn Virginia Resources ( PVR) and Alpha Natural Resources ( ANR) shed 11% and 10%, respectively.

Arch Coal ( ACI) dipped 9.8% after Tudor Pickering downgraded the stock to accumulate from the earlier buy rating.

Among other stocks, coal companies like Peabody Energy ( BTU) and Massey Energy ( MEE) were down 8.9% and 8.7%, respectively. Peabody is under pressure as investors are wary of oil price movements following the unrest in Libya.

Rio Tinto ( RIO) lost 8.5%. Last week, the company announced that it would revise its takeover bid for Riversdale Mining and increase the offer price to $16.50 per share, subject to acquiring more than 50% of Riversdale's shares.

Silver stocks like Pan American Silver ( PAAS), Alexco Resources ( AXU) and Silver Wheaton ( SLW) dropped 9.1%, 7.8% and 6.7%, respectively.