Dataset:  pillar_stability.dat

Source: R.K. Wattimena, S. Kramadibrata, I.D. Sidi, M.A. Azizi (2013). 
"Developing Coal Pillar Statbility Chart Using Logistic Regression,"
International Journal of Rock Mechanics & Mining Sciences," Vol. 58,
pp. 55-60.

Description: Logistic Regrssion relating Coal pillaar stability (Yes/No)
to width/height ratio and Strength/Stress ratio for pillars from 29 mine seams

Variables/Columns
Pillar ID   7-8
Mine Seam  9-38
Depth (meters) 40-46
Height (meters)  48-54
Width (meters)  56-62
width/height ratio  64-70 
Roadway width  (meters)  72-78
Uniaxial compression strength  (MPa)  80-86
Strength  (MPa)  88-94
Stress (MPa)    96-102
Strength/Stress ratio   104-110
Stability   118   /* 1=Yes  0=No  */