Name Upton Mine
Owner American Colloid Co.
Operator American Colloid Co.
Type Surface
Product Bentonite

Year

Production
(Upton Mine Only)
(tons)

Employees (Upton Mine+Upton Mill)
2010
Not Listed
Not Listed
2009
Not Listed
Not Listed
2008
0
0
2007
0
0
2006
0
0
2005
0
0
2004
0
0
2003
0
0
2002
59,537
25
2001
158,183
39
2000
143,915
33
1999
149,054
43

1998

346,818

57

1997

366,734

70

1996

724,204

70

1995

558,000

76

1994

621,297

84


Name Thornton Plant
Owner Black Hills Bentonite Corp.
Operator Black Hills Bentonite Corp.
Type Surface
Product Bentonite

Year

Production
(Thornton Mill Only)
(tons)

Employees (Thornton Mill)
2010
87,160
8
2009
73,448
8
2008
52,812
8
2007
13,632
4
2006
61,981
4
2005
38,571
2
2004
37,864
2
2003
23,288
2