Property, plant and equipment consist of the following:


September 30,
1999
1998
Estimated useful lives
(Thousands of U.S. dollars)
Building and building improvements
20 years
52.512
50.112
Machinery and equipment
7 to 20 years and unit of production
146.698
137.555
Vehicles
3 years
2.773
1.773
Office furniture and fixtures
3 years
443
441
Accumulated depreciation
(77.593)
(67.995)
124.833
121.886
Land
70
70
Construction in progress
60
5.758
124.963
127.714



Depreciation expenses for the years ended September 30, 1999, 1998 and 1997 were US$9.6 million, US$9.6 million and US$13.6 million, respectively, which were charged to cost of sales.