ZELIENOPLE — Excavation of the land that will be home for Murphy Tractor & Equipment Co. continued Wednesday with the blasting of rock using explosives.

The site is east of Route 19 next to Indian Brave Campground and south of the intersection with Wise Road. Top soil, rock and dirt is being removed to level out the sloping terrain.

Construction workers filled 60 holes with tubes filled with explosives that were detonated to loosen a plateau of rock of shale and sandstone.

Construction workers said the hardness of shale and sandstone varies. Some of it can be dug through while other areas can’t.

At 11:52 a.m., the blast occurred, leaving the hard plateau of rock into a smoldering pile of rubble. The explosion lasted less than three seconds.

Eight seismographs were used to record the vibrations and frequencies of the blast.

The seismographs registered vibrations from the blast at 0.065 inches per second, much lower than workers expected. The state limit is two inches per second recorded above 40 hertz.

A similar blast occurred later Wednesday afternoon for an adjacent rock plateau.

The rubble will be used for fill later on.

The new Murphy Tractor store will be about 44,000 square feet. A 6,000-square-foot shed also will be built.

Construction is expected to be done by February 2016, the same time the company’s lease for its store in Cranberry Township is up.

When that store moves to the new location, about 10 new jobs are expected to be created, bringing the total staff to 40.