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SURFACE BEDS.
uted to air slack, but are, we believe, the first stage of a creep or squeeze that if fully started may result in the complete collapse of the pillars in a large part of the area mentioned; it would bring down the roof, and unquestionably affect the surface. These indications, as before stated, are most serious in the Fair Lawn workings; they are observed on both sides of the tract and under the portion of the property where the Big Vein is present. Should a general squeeze take place in the Clark bed workings it would certainly affect the pillars and overlying strata of the Big bed and result in a very serious disturbance of the surface.
We deem it important to lay particular stress on the necessity for promptly taking measures to prevent the starting of a general squeeze or creep in the Clark bed at the Pine Brook colliery; for such a squeeze might cause breakages of gas, water and sewer mains, and resultant damages.
A point of particular weakness in this bed is under the Technical High School, near the intersection of Adams Avenue and Gibson Street. We have been informed that the Scranton Coal Co. has begun flushing culm into the workings under this important building, and that it is their intention to fill these workings as rapidly as possible. When this flushing is completed and a block of 1 or 2 acres is completely flushed, it will strengthen not only the point immediately filled, but have a tendency to support the roof for some distance on all sides of the artificial pillar thus introduced.
The old Lackawanna Iron & Coal Co. opened and worked the Clark bed by a drift from Boaring Brook gorge, near the Laurel line station. These old workings are now inaccessible, but maps inspected show an area worked over on the north and east sides of the river bank between the Delaware, Lackawanna & Western Railroad and Vine Street, and Madison and Clay Avenues. The maps show that very small pillars were left in. The old workings should be opened and artificial pillars made by flushing. The same plan is suggested for the Big, or Fourteen-foot, bed under Sanderson Hill, and for the old Iron Co. workings in this bed on the south side of Roaring Brook, under Spruk’s lumber yard and vicinity.
At the Manville colliery, operated jointly by the Delaware, Lackawanna & Western and the Delaware & Hudson Companies, the surface bed is the New County. This bed has been attacked recently, and is now being mined under the Green Ridge section of the city. It averages about 6 feet thick, with nearly 2 feet of refuse in several benches. We were informed that under the old leases the lessees were prohibited from mining this bed, but by a recent modification of the terms of certain of the leases they are permitted to extract one-third of the bed, leaving two-thirds as pillars to support the overburden. Considering the depth at which the bed lies and the char-978210—Bull. 25—12-------4