Year

Hardness

Calcium

mg/l

Magnesium

mg/l

Sulfate

Arsenic

mg/l

TDS

Alkalinity

pH

% of sulfate in TDS

1/14/92

128

43

5.0

68

.01

290

140

7.6

23.4%

1993*

56-78

270-303

25.7%

11/1/1993

148

485*

30.5%

1994

67

170

6

54

270

20.%

11/03/94

7,000 gallons

Sulfuric Acid

Twin Buttes Mine, Tank #72

12/19/94

5,000 gallons

Reclaim Water

1/18/95

373

121

16.8

65.9

.007-.013

280

23.2%

4/05/95

63.9

304

21.0%

7/19/95

71.4

242

29.5%

10/24/95

77.5

304

25.5%

1/08/96

4,000 lbs.

Sulfuric Acid

1/10/96

2000 lbs.

Sulfuric Acid

1/15/96

79.9

322

24.8%

2/21/96

1,850 gallons

Spent electr�lyte

3/26/96

3,000 lbs.

Sulfuric Acid

4/10/96

116

250

46.4%

6/12/96

13,263 lbs.

Spent electr�lyte

7/22/96

3,000 lbs.

Sulfuric Acid

8/07/96

81

322

25%

8/11/96

100 gals.

Sulfuric Acid

9/11/96

284

344

82.5%

1/13/97

98

390

25%

3/29/97

8,000 lbs.

Sulfuric Acid (93%)

7/11/97

2,798 lbs.

Sulfuric Acid

7/17/97

124

306

40.5%

10/27/97

146

448

32.6%

2/9/98

171

.011

522

32.8%

5/04/98

120,000 gallons

Leach Solution

5/05/98

40,000 gallons

Leach Solution

6/22/98

174

416

41.8%

9/21/98

205

530

38.7%

12/01/98

440

780

82.0%

2/10/99

327

113

11

327

655

49.9%

4/12/99

231

592

39%

10/26/99

428

145

16

461

620

74.4%

1/11/00

442

152

15

380

677

56.1%

4/19/00

296

640

46.2%

5/22/00

5,350 gallons

Leach Solution (H₂SO₄/Cu)

8/14/00

362

827

43.8%

10/18/00

403

693

48.7%

1/30/01

431

146

16

387

.011

734

52.7%

4/04/01

374

--

7/03/01

1,209 lbs.

Sulfuric Acid

8/14/01

402

751

53.3%

10/15/01

428

817

52.4%

1/31/02

39,375 gallons

Sulfuric Acid

2/06/02

462

157

17

463

.006-.009

856

54%

4/08/02

436

817

53.4%

7/10/02

470

823

57.1%

11/05/02

438

828

52.9%

2003

507

170

20

505

.007

900

56.1%

2/03/03

519

159

18

451

803

56.2%

4/19/03

8,722 lbs.

Sulfuric Acid

4/21/03

451

786

58.1%

2004

600

22

511

.007

940

7.1

54.4%