Table 4.

Analysis of potential factors affecting drilling performance related to environment.

Indicator	Component
	Physical environment	Safety and health guarantee	Management
Less dust	0.908
Clean construction site	0.827
Good air quality	0.812
No noise hazard	0.791
Bright light	0.728
Emergency plan and drill		0.927
Sufficient protective materials		0.882
Injury report and timely treatment		0.695
Reasonable safety system			0.898
Reasonable project schedule			0.824
Safety inspection and hidden danger investigation			0.634

Factor extraction standard: initial eigenvalues ≥ 80%, extraction method: principal component analysis.