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Lehigh Portland Cement Company
Lehigh Limestone Quarry Explosives Detonation

Omrod, Lehigh County, Pennsylvania
April 19, 1920
No. Killed - 6

USBM Final Investigation Report  PDF Format

See also: Lehigh Limestone Quarry Explosives Detonation, June 2, 1910
  Sandts Eddy Quarry Explosives Disaster, Mar. 26, 1942


A fatal explosion occurred in a limestone quarry during charging of six 5-5/8-inch chum-drill holes in a single row preparatory to blasting.

A line of Cordeau detonating fuse was placed in hole No. 2, but electric detonators were used in the hole.

After 12 or 13 cases of loose 40-percent nitro-starch powder had been poured into the hole, it was found that a space of 17 feet remained for stemming.  It was then decided that space for an additional case of powder might be obtained by tamping the charge.

Accordingly, tamping was done with a plunger weighing 30 or 40 pounds, about 3 inches in diameter, and 10 inches long.  The plunger was made of lead, with an iron core; it had an iron eye in the top, and a ¾-inch rope was attached to it.  This weight was ordinarily used for sinking explosives in wet holes, but not for tamping.

It is estimated that the tamping had continued at least 10 minutes.  The quarry superintendent went a considerable distance for a box of powder, returned, and reached a point about 10 feet from the hole when the charge exploded, instantly killing the man who was tamping and injuring the superintendent and the shovel runner, who was also nearby.

The flying rock killed five and injured one in another group, who were cleaning holes on the lower edge.  The explosion apparently was caused by hard tamping with the heavy metal plunger.

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