APPENDIX A. STATISTICAL SIGNIFICANCE OF TOTAL
COST REGRESSION EQUATIONS

A summary of each of the total cost equations, with corresponding square of the correlation coefficient (r2) and number of observations (n), is shown below. The r2 number indicates the scatter of the data points that are explained by the linear regression of the logarithmic values.

Open Pit Mine Models

Capital Cost

Operating Cost

Small open pit

160,000(X)0.515

71.0(X)-0.414

r2, n

0.981, 6

0.962, 6

Large open pit

2,670(X)0.917

5.14(X)-0.148

r2, n

0.995, 6

0.821, 6

Underground mine models

 

 

Block Caving

64,800(X)0.759

48.4(X)-0.217

r2, n

0.999, 4

0.998, 4

Cut-and-fill

1,250,000(X)0.461

279(X)-0.294

r2, n

0.959, 3

0.956, 3

Room-and-pillar

97,600(X)0.644

35.5(X)-0.171

r2, n

0.994, 3

0.988, 3

Shrinkage-stope

179,000(X)0.620

74.9(X)-0.160

r2, n

0.998, 3

0.992, 3

Sublevel-longhole

115,000(X)0.552

41.9(X)-0.181

r2, n

0.993, 3

0.997, 3

Vertical crater retreat

45,200(X)0.747

51.0(X)-0.206

r2, n

1.000, 3

0.997, 3

Mill models

 

 

Autoclave-CIL-EW

96,500(X)0.770

78.1(X)-0.196

r2, n

0.998, 3

0.995, 3

CIL-EW

50,000(X)0.745

84.2(X)-0.281

r2, n

0.999, 3

0.991, 3

CIP-EW

372,000(X)0.540

105(X)-0.303

r2, n

0.985, 3

0.922, 3

CCD-MC

414,000(X)0.584

128(X)-0.300

r2, n

0.990, 3

0.969, 3

Float-roast-leach

481,000(X)0.552

101(X)-0.246

r2, n

0.959, 3

0.989, 3

Flotation, one product

92,600(X)0.667

121(X)-0.335

r2, n

0.985, 3

0.966, 3

Flotation, two product

82,500(X)0.702

149(X)-0.356

r2, n

0.968, 3

0.964, 3

Flotation, three product

83,600(X)0.708

153(X)-0.344

r2, n

0.966, 3

0.966, 3

Gravity

135,300(X)0.529

67.8(X)-0.364

r2, n

0.986, 3

0.999, 3

Heap leach

296,500(X)0.512

31.5(X)-0.223

r2, n

0.971, 3

0.984, 3

Solvent-extraction-EW

14,600(X)0.596

3.00(X)-0.145

r2, n

1.000, 3

0.965, 3