For over 100 years in the 20th century, Italy has been monopolizing the international trade of natural stone, and “Made in ltaly” stone products can be seen everywhere. Regardless of its output, import and export volume, it has long been the world’s top, and its product quality and mining and processing equipment are also world-class. Italy, rich in marble resources, is also renowned for its stone craftsmanship and design, which is second to none in the world. Italy has always attached great importance to the use of stone in residential buildings. Marble and other stones account for 56% of the total usage in residential buildings, and 70% of households tend to use stones because they are elegant and natural. This article introduces you to the five major characteristics of the Italian stone mining industry, which is also why people like Italian marble.
1、 Advanced mining equipment, fully mechanized mining, and high overall productivity
Almost every mining area in Italy uses a mast crane for lifting, with a maximum mast arm length of 70 yards and a lifting capacity of 50T. The mine is divided into two mining methods: open-pit mining on slopes and open-pit mining on depressions, with the main method being full sawing mining using a combination of bead saws and arm saws. There are also cases where car mounted rock drills are used for stone grading and waste shaping. Mines are rarely directly equipped with chain arm saws, and most use rental methods. The mining equipment configuration of each mine usually includes: one mast crane, one loader, one excavator with a rock excavation bucket above 320 (usually CAT340345 and 365 or Komatsu 450), 3-4 bead saws, and one fixed waste shaping machine.
All mines in the mining area are equipped with multiple chain saws, diamond bead saws, and two kinds of cutting equipment for joint operation according to the mining output. Multiple Carter or Volvo are equipped. Komatsu fork loader cooperates with the mast to lift off the platform, lift, transport, and load and unload trucks. Not only is the equipment used in mines advanced, but the manufacturing of mining equipment is also leading worldwide. The equipment manufacturing enterprises and products for mining and stone processing are well-known worldwide, and the manufacturing technology for mining and processing equipment is leading the world trend.
The marble mining equipment in Italy can be considered excellent, and the actual number of production workers is very small. There are only a few people on a large mining face, and the average annual production of waste materials per person is 500m ³， The total labor productivity is among the highest in the world. Efficient output benefits from advanced mining technology and equipment, as well as the comprehensive and skilled labor skills of production workers, as well as the dedication and professional quality of employees. The production workers in Italian mines are versatile, capable of operating mining equipment, lifting equipment, and even driving trucks for transportation. Everyone has a serious work attitude and a high level of self-awareness. The level of equipment automation is very high, and one person can take care of multiple devices. After the cutting equipment stops, the workers continue to operate the forklift for loading and transportation.
2、 Adapt to local conditions and have diverse mining methods and methods
Multiple mining methods can be seen in Italian mining areas, including slope open-pit mining, depression open-pit mining, and cave mining. The development methods include crane development, highway transportation development, and joint development. All mining and development methods are based on the location characteristics and terrain conditions of the ore body, tailored to local conditions, and reasonably planned and designed.
For ore bodies with complex terrain conditions, open-pit mining on mountain slopes is often used. The development methods include single truck transportation and joint development with truck transportation and mast cranes. If the ore body extends deep underground, a sunken open-pit mining method is adopted, and a mast crane is used for transportation and development. The characteristics of sunken open-pit mining are that the mining area is small, the thickness of the ore layer is large, and the mining operation space is small. A single mast crane can meet the needs of waste rock lifting by the waste material machine. If the mining pit area is large and a single mast crane cannot cover the mining area, multiple mast cranes need to be equipped for lifting to meet the needs as a benchmark.
Mines with a large inclination angle (over 35 º) usually adopt a layer wise mining method. After large blocks of stone slide onto the bottom platform of the working face, they are separated by layer wise hole guide ropes, and a bead saw is used for vertical and layer wise cutting and separation. The large blocks of stone are overturned along the layer and then reshaped. If the dip angle of the ore layer is too large, the parallelogram can only be used to separate the three-dimensional shape, and the bead saw can be used for horizontal cutting and separation. After the side is overturned, the parallelogram surface can be trimmed.
For ore bodies with large burial depth, large amount of surrounding rock stripping, high cost of open-pit mining, and high difficulty, half of them will be excavated through underground mining – tunnel mining. Most of the mines in cave mining were initially open-pit mining for a long period of time, and then followed by tracking the direction of the ore veins to implement cave mining. There are also cave mining mines that directly adopt cave mining methods for mining on the premise of verifying the occurrence of ore veins. In addition to meeting the requirements for ore body location, the implementation of cave mining also requires specialized cave mining equipment, such as chain arm saws and diamond bead saws, which are essential for development.
Cave mining has the following advantages: firstly, tracking mining along the best vein direction, reducing the amount and cost of stripping; Secondly, the integrity of the ore body is good, the waste material rate is high, and the labor efficiency is also high; The third is to protect surface vegetation, and operations can continue throughout the year, regardless of wind or rain. The biggest advantage of cave mining is that it is easy to understand the laws of geological changes in the ore body, and can be mined along the best ore layers to obtain high-quality and expensive waste materials. Of course, the mining cost is also high. The cost of cave mining is about 1.1-1.2 times that of open-pit mining, mainly reflected in selecting high-quality and complete vein mining, avoiding areas with poor color and crack development, and using anchor rod reinforcement engineering to fix crack areas.
At present, 20% of the marble mines in the Carrara region implement cave mining. The government is in need of environmental protection and the renovation of the Carrara region’s environment and scenic areas, requiring new marble mines to adopt cave mining methods in order to obtain approval. In order to extend the mine’s lifespan and expand the scope of open-pit mining, open-pit mines will also choose good ore veins to track cave mining towards the belly or deep part of the mountain.
3、 All mines have standardized construction and mining
The construction and mining activities of most marble mines in Italy are highly standardized, and infrastructure construction is highly valued. From transportation systems to power and water supply, from mining platforms to waste material storage yards, from waste material segmentation to slag disposal, all site facilities and mining processes have been carefully planned and designed, with clear and orderly organization.
Mines developed by road transportation strictly follow the requirements for road width and steep slopes. The main transportation roads in the mining area are paved with asphalt on the ground, and signs are set up at downhill and sharp turns to remind vehicles, which is completely the same as the facilities and traffic requirements of regular roads.
For completely open-pit mining on mountain slopes, even the steepest terrain requires the road to be built to the mining site, and the slope requirements are very strict, and there will never be sections that exceed the requirements. The mining site has a large relative elevation difference and complex terrain conditions. No matter how much investment is made in road construction and the difficulty of road construction, there will be no compromise. In terms of creating transportation and mining conditions, there will be no shortcuts, let alone the barbaric mining method of using large guns.
During the mining process, the height and width of the steps, the sequence of operations, and the direction of advancement are all done according to the design. Even in the tunnels of the tunnel mining mine, the mining sequence of steps from top to bottom must be strictly followed. Most sunken open-pit mines use mast cranes for transportation and development, while some mines also use highways and cranes for joint development. The installation location of mast cranes is very important, taking into account not only the coverage of the crane arm but also the long-term use factor. Half of them are installed on the edge that is not in progress. With the increase of mining depth, it is also important to set up and function water collection and drainage facilities, and production should not be affected by water collection.