Block Slabbing at the Quarry
INTEGRATED SYSTEM
The IN-LINEA arrangement is the first integrated system that extracts, processes, and disposes of waste directly in the quarry. The in-line production process comprises three phases: extraction, block squaring, and slabbing.
Raw material is extracted using quarry machines on rails and with a single diamond wire. The efficient exploitation of dimensional-stone quarries depends on an intelligent approach to working the quarry front, to obtain high- quality blocks. The front has to be properly exposed and prepared before block extraction begins.
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Once extracted, the raw stone blocks are transferred to the second stage, where WIRES monowire machines are used, usually in gantry configuration (i.e. with the block held on a fixed carriage and the MDW moving), or using a WIRES specially designed block squaring system. With the gantry configuration, block handling is minimized; with the dedicated block-squaring center, a block can be re-sized in one pass.
The main advantage of the new integrated production system is in the third phase, with a WIRES multiwire machine (EPICA) with up to 65 diamond wires installed in gantry configuration on the production line. With 65 wires, a medium-size block of 2600mm x1800 mm can be cut into slabs in a single machine descent.
New manufacturing technologies, combined with advanced new materials, Wires / CO.FI.PLAST to design a new generation of compact cutting machines with an innovative diamond wire tensioning system to guarantee the optimum tensioning of each diamond wire. The C-shaped structure minimizes space requirements and maximizes machine stability.
The three component parts of the integrated production system are interconnected via a rail line for the gantry-cutting machines. The machine structure and the materials used including surface treatments and paint are designed to protect the critical machine components.
The concept of a complete slab production system within the quarry site offers great advantages both from the economic and ecological points of view. Material movement is minimized; the conventional system of transporting raw blocks to a processing factory inevitably involves waste transportation, fuel costs, air pollution and non-productive time.
THE DIAMOND WIRE
Click photo to enlargeThe optimum selection of the diamond-wire specifications is critical for efficient and cost-effective cutting of stone; as with all diamond impregnated tool applications, the bead matrix should wear at the same rate as the tips of the protruding diamond particles. The interactions involved in the removal of the various constituents of a stone material has been the subject of numerous scientific and practical investigations over the years.
A good synergy between the diamond wire and the cutting machine guarantees an optimal cut. The beads of a diamond wire for block extraction are generally 10-11mm diameter, whereas 6-7mm beads are typically used for multi-wire slabbing. MDW machines have to produce identical parallel slabs, with a smooth and regular surface with no defects.
CO.FI.PLAST has designed and developed a new generation of diamond wires with a reduced cable and bead diameter providing improved cutting efficiency. Many factors influence optimization of the diamond wire. They include improved bead production parameters — particularly sintering — and the optimum selection and combination of raw materials including metal powders and diamond abrasive.
Ing. Alice Tori is a research project supervisor from the Brocco group; Dott. Romina Brocco is a member of the owner’s family administering the Brocco group; Paul Daniel is a freelance writer specializing in stone-processing technology and a contributor to Stone Update.
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