Mine Performance Assessment by Means of Stochastic Frontier Analysis

Table 2

Maximum likelihood function estimates, Stage-1.

Variable	Coefficient	Standard error	z-value	p value
Constant:	: -42.870	17.3401	-2.470	0.013
lnL	: 2.174	0.8205	2.650	0.008
lnO	: 0.694	0.5559	1.250	0.212
lnE	: 1.112	0.4245	2.620	0.009
Variance parameters for composed error
	1.0663	0.3120
	0.7444	0.0639

Log likelihood function = 2.047.
; .
Notes: L: total man-shift hours paid; E: electrical energy consumed by bucket wheel excavators; O: overburden removed in bank cubic meters.