Granite Quarrying and Memorial Manufacturing Techniques

Quarrying

Granite is taken from quarries using a variety of tools and personnel. Often these blocks are as large as four feet tall, eight feet wide, four feet deep, and can weigh as much as 10 tons.

Granite is cut from the "bed" of the quarry with a jet piercing machine that produces a flame burning at approximately 3,000 degrees Farenheit. This high-velocity flame, created by burning oxygen and fuel oil, is directed at the granite to be removed, causing a continuous flaking action. As the flame nozzle is moved up and down, a channel is created around large sections in the quarry.

In some quarries, diamond wire saws are used. A long loop of small steel cable, impregenated with industrial diamond segments, cuts the sections free from the bed of the quarry. After a section has been completely wiresawed or channeled by the burner, it is separated from the bottom by explosives. (Watch video of a detonation.)

Likewise, when high-speed drills are used, rows of drilled holes are loaded with explosives. The explosives are detonated to free the sections of granite on all sides and on the bottom.

The large sections are then broken into workable sizes by wedging. In this process, steel wedges are driven manually into holes previously drilled along the desired line of cleavage. The sections are readily forced apart and cross-wedged into rectangular blocks. Large cranes, or derricks, lift these blocks to the quarry's rim. Requirements for monumental granite are exacting, and only about 50 percent of the granite removed from the quarries finds its way into finished monuments. The remainder is consigned to commercial applications such as street curbing and gravel, or is sent to "grout piles" as waste products.

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