294 



The Philippine Journal of Science 



1915 



proved for a distance of approximately 200 meters down the 

 dip and 150 meters along the strike. 



Nevertheless the fact that the enterprise was abandoned just 

 when its success seemed assured and was never resumed made 

 the records appear questionable to American interests which 

 came into control of the Uling field recently, and exploration was 

 renewed to verify their correctness. 



The recent exploration at Uling, which was conducted under 

 my supervision, began with a slope entry on the 5-meter outcrop. 

 This slope followed the floor of the bed for a distance of about 

 20 meters from the intersection of the bed with the surface, 

 where a fault was encountered. This fault is parallel to the 

 strike of the coal, but dips in the opposite direction — ^that is to 

 say, the coal dips about 35° westward, while the fault dips about 

 30° eastward. The coal is truncated sharply along the fault, 



Bed 3.5 meters thicli] 

 1. 35 mtlenjood cool 



Outcrop loose blocks of coal 



Outcrop 5.6 meters thick 

 i.B'metersgoodcoal 



TyyTyTp^t^ Tunnel 



'outh 



. .,„„.V///% 

 •<<^ Sh ale and Sandstone) 



Bed Z 7 meters thick 

 1 1.91 meters good cool 



Fig. 2. Sketch, showing in section exploration work on a 5-meter coal bed at Uling, Cebu. 



and there is little evidence of drag or movement along the fault 

 plane. It was fairly clear, however, assuming that a normal 

 fault had caused the displacement, that the continuation of the 

 coal beyond the fault would be encountered by following the 

 fault upward; in other words, the outcrop coal dropped along 

 the fault. 



It was decided to do no more work on the slope because of 

 the inconvenience entailed in changing the grade from the fault 

 plane forward, but instead to drive a new tunnel from a point 

 about 50 meters farther north along the outcrop. This tunnel 

 was driven so as to drain itself, and its portal was located about 

 10 meters lower than the outcrop. The fault plane was inter- 

 sected at 48 meters from the portal, and at 121 meters the 

 tunnel reached the coal bed beyond the fault. The last 20 meters 

 of the tunnel were in sandstone and shale which showed no 



