Marble

Marble is one of the favourite types of rock used in formal settings. Also, the fact that it is easy to work with makes it useful for many different kinds of projects. The Romans and Greeks were the first to use marble for their sculptures; the main reason being its soft nature. It was easy for the Greeks and Romans to use their primitive tools to cut intricate shapes from the marble.

Formation

Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Metamorphism causes variable recrystallization of the original carbonate mineral grains. The resulting marble rock is typically composed of an interlocking mosaic of carbonate crystals. Primary sedimentary textures and structures of the original carbonate rock have typically been modified or destroyed.

Extraction

Marble is extracted from marble quarries today with almost the same techniques as were used in ancient times. Excavation and clearing of the soil layers are continued until the marble layers are located. Extraction operations are initiated by the cutting of step-like banks of rock blocks descending from the top to bottom and from these steps the individual marble blocks are split off.

The process of block extraction is conducted by quarry masters and workers using rock drills, diamond wires, etc. Channels are cut by the stone cutters between the main rock and the base of the block according to the required dimensions for the block.

In ancient times, wooden wedges were inserted into channels between the main block and the desired block and soaked with water. The marble blocks were parted from the main rock due to the pressure exerted through the swelling of these wooden wedges, as they were repeatedly soaked with water. The extraction methods employed were almost always the same, except for slight differences caused by the size and type of the block.

Processing

At the processing plant the marble block is set up so that different pieces of marble can be cut out of the large blocks. A giant saw is used to cut the marble into more manageable pieces.

To make large slabs, the marble is cut using Gangsaws. These have long steel blades with synthetic diamond teeth. They cut the marble block into slabs of required thickness. It can take anywhere between 2 days to a week to cut the marble into useful slabs.

Another way to cut the block is by using giant saws to cut up the marble into more manageable pieces. Some of the blades on the giant saws are up to 3.5m wide. It can take up to a week to cut the marble enough to break into usable sections.



 
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