Marble is a metamorphic rock primarily composed of carbonate minerals, most commonly calcite (CaCO₃) or dolomite (CaMg(CO₃)₂), that has recrystallized under heat and pressure. It forms when limestone is subjected to these metamorphic conditions, causing the calcite crystals to recrystallize into a denser, crystalline rock with a typically non-foliated texture.
Marble is typically extracted from large stone quarries located in mountainous regions. The extraction process involves the use of specialized equipment and a careful extraction of stone blocks. These blocks are then removed from the quarries and processed through cutting, polishing, and shaping using specialized machinery to achieve the desired dimensions (Extraction and Production of Marble | ADK MARBLE, 2024).
Marble extraction from quarries involves a controlled, multi-step process designed to safely and efficiently remove large blocks of marble while minimizing damage. The key steps are:
Locating and selecting the quarry site: Geologists identify potential marble deposits by examining exposed rock outcrops and conducting core drilling with diamond-tipped drills to assess marble quality and purity. Permissions and licenses are obtained before mining starts.
Preparation of the quarry: The land is cleared of vegetation and debris. An overburden layer (soil or non-target rock) is removed. A bench wall or vertical planar face is created in the quarry using drilled holes aligning vertically and horizontally, forming a precise cutting surface.
Drilling and cutting: Pneumatic and down-the-hole steel drills bore holes vertically and sometimes horizontally into the marble mass. Synthetic diamond wire saws or diamond-coated chainsaws cut through the marble along these drilled holes to separate large blocks from the quarry face. Explosives may be used in some quarries for controlled rock fragmentation but are less common due to risk of fracturing the marble.
Block extraction: The cut marble blocks, each weighing several tons (often upwards of 15,000 lbs), are detached carefully using cranes, excavators, and sometimes bulldozers equipped with heavy-duty grips. Blocks are lifted out to prevent damage and transported to processing plants.
Transport and processing: Blocks are transported on cushioned vehicles to milling facilities where diamond saws cut them into slabs of desired thickness (commonly 7 to 9 feet in length). Slabs are then polished, sometimes treated with resin to fill minor cracks, and finished for use.
Historically, marble was mined manually with chisels, hammers, wooden wedges soaked in water to expand, and wire saws, but modern extraction relies heavily on advanced machinery and diamond tools for precision and efficiency (How Was Marble Mined in the Past?-Stonecontact.Com, n.d.)
