New concepts in quarrying technology
Pellegrini Meccanica is one company that has continued to update its products while also developing new equipment. "In the past, Pellegrini Meccanica has created some product lines and new technologies that have revolutionized the industry: diamond wire machines in collaboration with Diamant Boart, who developed the wires, and flaming and bushhammering systems, to name the most important," said James Gobbett of Pellegrini. "Our basic concept has been to use machines that are relatively simple mechanically, ensuring low costs, high reliability and easy maintenance, with sophisticated controls and today's software to exploit the capabilities of the machines and of the diamond wire or other tools to full effect."
An example is the recently introduced Chain Saw (CH60) for marble and limestone, which uses 100% electric drive systems. "We knew this would lead to better energy economy, but we were surprised by the effects on tool costs: halved," Gobbett said. "And this while the cutting speeds in some cases were almost double those seen with traditional machines."
The company's quarry wire saws have been refined and simplified regarding their range and construction, according to Gobbett. "There are three basic machine types - TD25, 55 and 65 - all with direct power transmission," he said. "In addition, the Diesel workhorse TDD 100 can cut anything of any size, and derrick cranes, used to cut 50-ton rough blocks in some countries, are built here with booms up to 70 meters long."
A new concept in the quarry is also emerging, according to Gobbett. "A single multiple wire machine, the Pellegrini Meccanica Polywire, can be put not only in processing areas, but also in the quarry, even outdoors," he said. "This machine can slab any type of stone block. The Polywire can cut any shape block as well - even 'potatoes' - without production loss. It is effectively an open frame gangsaw for granite and marble, with all the further advantages due to the use of diamond wire."
A similar application is made possible using Pelligrini's single wire Diamantfil Roller. "The blocks are on the ground, and you can set the machine to cut slabs or trim the blocks as you wish," Gobbett said. "The automatic systems, using our own software, on both the Polywire and Roller are such that cutting speeds adapt to the block without operator action to ensure maximum production. Both of these machines also have a full set of safety, surveillance and messaging systems, to ensure easy operation and diagnostics." Pellegrini is represented in the U.S. by Precision Stonecraft of Atlanta, GA.
Companies such as Fantini have also contributed a significant amount of time to studying new equipment for quarrying and the areas in which previously used machinery need improvement. "The arrival of the Model GU 50 machine for underground quarries has given very good results both for output increase and the easier use of the machine," said Marco Turrio of Fantini.
This new chainsaw machine is designed to save time in the shifting of the machine as it moves on tracks. The cutting arm is capable of making both horizontal and vertical cuts on different planes, as well as "back cut" cuttings, according to the company. The machine is adaptable to the narrow rooms of underground quarries and can be custom-built to fit these dimensions.
The GU 50 can make dry cuts in many types of stone, except granite. It can be equipped with a variety of inserts and has a hydraulic system that continually regulates all of the cutting movements as well as the positioning and moving of the machine. The GU 50 features a mobile wire control panel, on which the main push button controls are installed. The panel works by a remote control system. This machine can also be equipped with arms of differing lengths to accommodate the hardness of varying types of stone.
Fantini has also introduced the SQB/P squaring machine, designed to square stone blocks before they are treated. According to the company, the portal frame machine moves on rails and is equipped with a cutting arm, on which hard metal or PCD tools fixed on a chain are run in suitable slides. The SQB/P machine was built for the sectioning of hard or abrasive stone blocks such as sandstone, travertine, marble and some types of limestone.
The machine is completely electro-hydraulically controlled, according to the company. The translation of the trolley is controlled by a hydraulic motor with adjustable speeds, and the chain advancement is controlled by an electric motor with a fixed speed. The machine can handle dry cuts and is the best solution for any climatic and environmental condition, according to the company.
The SQB/P has a laser arm to locate the cutting point of each stone block to be cut. The machine can store and remember data such as the cutting point, the speed at which the arm is lowered and the chain's speed. "Therefore, once the laser system is aimed at the cutting point of each block, the machine cuts until the job is done without the presence of an operator," said Turrio.
Quarriers can also turn to Korfmann for chainsaw quarrying technology. Korfmann manufactures a variety of diamond chainsaws for extracting dimensional stone such as marble, limestone and conglomerate stone, sandstone, slate, serpentine, travertine and volcanic stone among others. These saws feature cutting depths of up to 3,250 mm. For underground quarrying, Korfmann stone-cutting machines cut vertically and horizontally with cross section heights of 3,000 to 4,500 mm, cross section widths of 6,000 to 7,000 mm and a maximum cutting depth of up to 2,600 mm, depending on the stone.
GE Superabrasives has also played an important role in the development of quarrying equipment. Originally developed for drilling applications in the oil industry, the company's Stratpax blanks consist of a layer of polycrystalline and man-made diamond and cemented tungsten carbide, which is produced as an integral blank through a high-temperature, high-pressure technique. According to the company, the resulting blank is as hard and wear-resistant as diamond, complemented by the strength and impact resistance of cemented tungsten carbide. The polycrystalline layer on the Stratapax blank ensures a continually sharp edge even as the blank wears in the application. As the initial layer of diamond crystals is slowly worn away, a layer of sharp new crystals is exposed. This process continues throughout the life of the blank. These blanks are utilized on such machinery as the Korfmann ST 450 VH chainsaw.
High Tech Stone of Elberton, GA, has also made substantial contributions to quarry machinery through its distribution of new equipment from abroad. The Stonesaw DH 55, a fully hydraulic diamond wire saw, is produced by DWireTeknikk in Norway, and marketed in the U.S. by High Tech Stone.
The Stonesaw DH 55 has a fully independent tensioning and a wire speed system which provides an easy and fully controlled sawing operation in all circumstances, according to Per Ivar Karlsen of DWireTeknikk. A control panel clearly indicates power, wire speed and movement, and the machine features a simple and well-proven diesel hydraulic design, according to the company. The saw ensures easy operator training, and with the 24-volt DC system, it provides no electrical hazards during maintenance or service.
New lines of diamond wire quarry saws are also available through Granite City Tool Co. of Barre, VT, and St. Cloud, MN. Manufactured by Ogyu of Japan, these saws are offered with 50-hp electric motors or 75-hp diesel engines and can be ordered in vertical-horizontal cutting or vertical cutting models.
These saws simplify the cutting procedures in a granite quarry, said Mark Eisenwinter of Granite City Tool Co. "All you have to do is open a vertical and a horizontal hole with a drill, which should meet together so the diamond wire can be passed through," he said. "According to a customer of ours, it is not very difficult to make the holes meet each other. Then, the stone can be cut. Usually, the face of the mountain is drilled, and the bottom is blasted. If the diamond wire saw is the vertical-horizontal type, however, it is feasible to cut the bottom by diamond wire saw as well, since the flywheel can be inclined to cut horizontally."
The Ogyu diamond wire saws can handle 2 square meters (22 square feet) of stone cutting per hour for hard white granite, and according to Eisenwinter, 5 square meters (54 square feet) are cut by one linear meter diamond wire for hard white granite, although this varies for the type of wire and the type of granite.
Granite City Tool Co. also distributes the PRS-80 hydraulic power rock splitter manufactured by Soo-Ho Industrial Co. of Korea. "The hydraulic motor powers six 31-inch cylinders that produce between 950 and 1,235 tons of splitting force," said Eisenwinter. "This model will split approximately 9 square meters of stone per hour."
According to the company, this system provides a safer means of splitting quarry stone than dynamite blasting and it meets the requirements for noise regulations. "This is also one of the least expensive and most efficient ways to split stones from quarries," said Eisenwinter.
W.F. Meyers Co., another manufacturer of quarrying equipment, has challenged its customers to revolutionize their stone cutting operations by using the company's diamond belt saws. The W.F. Meyers diamond belt saw quarry machine was introduced in 1984, but according to John Slate of W.F. Meyers, the saw revolutionized the stone industry like no other machine since the introduction of the channeling machine in the early 1900's.
Used in quarrying limestone, marble, slate, sandstone, bluestone and other stones throughout the U.S., Canada and the world, the diamond belt technology allows this 8,000-pound machine to run on track sections, which can be easily moved and leveled. The machine can cut up to 16 feet deep at a rate of 1 to 4 inches per minute. The saw's lifetime lasts through 5,000 to 30,000 square feet of cutting, depending on the material being cut.
"The machine is very quiet and environmentally friendly, and it comes equipped with a turnaround feature as well as an automatic shutdown," Slate said. "This allows the machine to cut on both sides of the track for an adjustable cutting width between 4 feet, 3 inches and 5 feet, 6 inches. In addition to the standard vertical machine, a horizontal undercutting machine is offered, which allows blocks to be brought out of the ground with a smooth surface on all six sides."
With the advancement in quarrying technology and the contributions many quarrying equipment manufacturers are making, the stone industry has progressed significantly within the last few years. New methods are constantly being made available to help quarriers streamline their businesses and increase their profits.