MINING CONDITIONS UNDER CITY OE SCRANTON, PA.
46
Under a portion of the territory mentioned, the Big or Fourteen-foot bed is present. It was partly worked over many years ago by the old Lackawanna Iron & Coal Co. The area underlain by this bed is what is generally known as Sanderson Hill, and is clearly shown in Plates Nos. 2, 3, and 4. The old workings in the Big bed are inaccessible, except a very small portion that extends from the Pine Brook Traveling Way to a point under the Central High School. Although there may be other openings to the workings in this bed, they are unknown to us. From information furnished by various persons, it is believed that the old maps of the workings in this bed are reasonably accurate.
The part of these workings that was inspected showed the pillars in good condition and the roof over the openings fairly sound, although local falls have occurred in many openings preventing access to points beyond. According to our information no serious “creeps” or “squeezes” have occurred in this bed, and unless some disturbance takes place through subsidence of the measures below it not much danger is to be apprehended from a general creep in this bed. We are, however, of the opinion that detailed investigations should be made by reopening small holes through the local falls mentioned above, and by sinking shallow shafts at various points for the purpose of makiug accurate surveys of the mine workings. These should be maintained as avenues through which to conduct or transport material for filling. It is deemed especially important that these openings be completely filled, on account of the nearness of this bed to the surface, and the value of the surface improvements. Methods of protection will be described in another chapter.
Below the Big bed the next bed that has been worked from the Pine Brook shaft is the Clark. The New County bed has not been worked at Pine Brook, but it is present and will doubtless be mined in the future. The Pine Brook workings include what was formerly the property of the Fair Lawn Coal Co., between Gibson and Ash Streets, and Capouse and Quincy Avenues. The usual rule of leaving approximately one-third of the coal was generally followed in the major part of the workings from the Pine Brook shaft, but much less than one-third was left in the Clark bed where worked from Fair Lawn. This bed is from 8 to 11 feet thick; a bench of coal at about the middle of the bed that is considerably softer than the balance was noted. This bench is affected by what is known as “air slack,” causing it to chip and flake off, and to show the first signs of any undue pressure on the pillars.
A very large proportion of the pillars inspected an this bed show unmistakable signs of pressure, particularly in the Fair Lawn workings and outwardly from this area for a considerable distance. These signs of pressure on the pillars can not, in our opinion, be solely attrib-