Effect of Shaft Pillar Extraction on Stability of Main Shaft: A Case Study at Xincheng Gold Mine, China

Table 5

Variance analysis of the orthogonal experiment.

Source of the variance	Quadratic sum	Degrees of freedom	Mean sum of square	F	Fα	Significance
Lateral pressure	0.002088	2	0.001044	12.626479	3.98	Very high
Distance	0.002317	2	0.001158	14.006953	3.98	Very high
Dip	0.003780	2	0.001890	22.855622	3.98	Very high
Thickness	0.000168	2	0.000084			Low
Location^△	0.000047	1	0.000047			Low
e^△	0.000694	8	0.000087			Low
e′	0.000910	11	0.000083			Low
In total	0.010005	17				Low

“△” indicate that the mean sum of square of this factor is smaller than that of error term, being incorporated into the error term.