6. Inventories

The components of inventories are as follows:


	September 30, 2011			December 31, 2010
(In thousands)				(Audited)
Raw materials	$	123,393		$	126,401
Work in process		8,658			6,395
Finished goods		77,770			73,710
Supplies and materials		109,567			102,720

Inventories at FIFO or average cost		319,388			309,226
Excess of FIFO or average cost over LIFO cost		(75,013	)		(68,084	)

Inventories, net	$	244,375		$	241,142

An actual valuation of inventory under the LIFO method is made only at the end of each year based on the inventory levels and costs at that time. Accordingly, interim LIFO calculations must necessarily be based on management's estimates of expected year-end inventory levels and costs. Because these are subject to many factors beyond management's control, interim results are subject to the final year-end LIFO inventory valuation.