The main production system of underground mines – 2

2 Underground transportation

1) Classification of underground transportation

Underground transportation is an important link in the mining and production of underground metal ore and non-metallic ore, and its work scope includes stope transport and roadway transportation. It is the transportation channel of continuous stope, tunneling face and underground mine warehouse, filling mining area or ground mine warehouse and waste rock field. Stope transport includes gravity self transport, electric rake transport, trackless equipment transport (shovel transport, loading machine or mining vehicles), vibration mining machine transport and explosive force transport, etc. The roadway transportation includes the transportation of the stage grade lane and the inclined lane, that is, the roadway transportation between the stope funnel, the stope patio or the roadway below the slip well to the underground storage bin (or adit entrance).

The classification of underground transportation according to the transportation mode and the transportation equipment is shown in Table 3-4.

Classification of underground transport

In order to ensure the normal and effective operation of underground transportation, the necessary transportation auxiliary equipment is indispensable.

2)Underground transportation system

The transportation system and transportation mode of underground mine are generally determined in the development and design of ore deposits. The determined principles should consider the occurrence conditions of the deposit, the development system, mining method, mining scale, production service life, the development status of transportation equipment and the management level of the enterprise. It should be advanced and reliable in technology, reasonable and advantageous in economy, safe in operation, convenient in management, small in energy consumption and less in investment.

(1) Rail transit

Rail transportation generally refers to locomotive transportation, which is the main mode of transportation of underground mines at home and abroad. Rail transportation is mainly composed of mining vehicles, traction equipment and auxiliary machinery and other equipment, often composed of effective transportation system with rake ore, loading, belt conveyor or trackless transportation equipment, in the production process can transport ore, waste stone, materials, equipment and personnel. It is one of the main factors that organize the production and determine the production capacity of the mine.

The advantages of rail transportation are wide use, large production capacity (determined by the number of locomotives), unlimited transport distance, good economy, flexible scheduling, and can transport a variety of ores along the bifurcation line. The disadvantage is that the transportation is intermittent, the production efficiency depends on the work organization level has limitations (generally 3 ‰ ~5 ‰), and it is difficult to ensure the transportation safety when the line slope is too large.

Running on the track is the main mode of horizontal long-distance transportation. The track gauge is divided into standard gauge and narrow gauge. The standard gauge is 1435mm, and the narrow gauge is divided into 3 kinds: 600mm, 762mm and 900 mm. According to the different gauge, locomotive can be divided into standard gauge locomotive and narrow gauge locomotive; according to the different power used, mining locomotive can be divided into electric locomotive, diesel locomotive and steam locomotive. Steam locomotives have been basically eliminated, and diesel locomotives are generally only used for the surface. The electric locomotive is driven by electric energy, according to the nature of the power supply, the electric locomotive can be divided into DC electric locomotive and AC electric locomotive, the DC electric locomotive is the most widely used. Now, there are many users began to use the frequency conversion motor car. According to the different power supply mode, DC electric locomotive is divided into wire type electric locomotive and battery electric locomotive, and the vast majority of non-coal mine underground use in China are wire type electric locomotive.

With a simple structure, low cost, convenient maintenance, large locomotive transportation capacity, high speed, high electricity efficiency, low transportation cost, it is the most widely used. The disadvantage is that the rectification and wiring facilities are not flexible enough; the roadway size and pedestrian safety affect the spark between the pantograph and the line is not allowed in the initial construction of serious gas mines, but in the long run, the total cost of the motor is much lower than that of battery motor. The DC voltage is 250V and 550V.

Battery electric motor is a battery to supply electricity. Battery is generally charged in the underground motor garage. After the battery on the motor is used to a certain extent, it is advisable to replace the charged battery. The advantage of this kind of electric motor is that there is no spark tipping danger, suitable for the use of gas mines without necessary line, flexible use, for small output, irregular roadway transportation system and roadway tunneling transportation is very suitable. Its disadvantage is that the initial investment of charging equipment has low electricity efficiency and high transportation cost. Generally, the wire motor is used in the mining stage, and the development stage can use the battery motor vehicle to overcome the external conditions. In the return air roadway with blasting gas, should not be used, high sulfur and natural fire danger mine, explosion-proof battery motor should be used.

In addition to the above two kinds of electric motors, there are duplex energy electric motors, mainly can be divided into a wire —— battery type electric locomotive and a cable type electric locomotive. There is an automatic charger on the battery electric locomotive, which can improve the utilization rate and use the flexibility. When working in the transportation lane, the cable power supply, but the transportation distance of the cable power supply shall not exceed the length of the cable.

Internal combustion locomotives do not need to line, low investment, very flexible. However, the structure is complex and the exhaust gas pollutes the air, so it is necessary to install the exhaust gas purification device at the exhaust port and strengthen the roadway ventilation. At present, only a few mines in China are used in the well-ventilated adit surface joint section and surface transportation, and more mines are used in foreign mines.

Mining vehicles transport ore (waste stone), people and vehicles vehicles, material vehicles, explosive vehicles, water trucks, fire trucks and sanitary vehicles and other special vehicles.

(2) Trackless transportation

In the 1960s, with the improvement of the underground trackless equipment, the underground trackless mining technology has also been developed rapidly.

Underground mining automobile is a self-propelled vehicle specially designed for underground mine. It is the main transportation vehicle to realize the trackless mining technology, and it has the advantages of mobility, flexibility, multi-energy and economy. Underground mining vehicles are widely used in all kinds of underground mines with suitable conditions for enhanced mining, which can not only improve the labor productivity and output of underground mines, promote the continuous expansion of production scale, but also change the mining process, mining method and tunneling and transportation system of such mines. Especially with the development of mine automation, intelligent mining and other technologies and systems in recent years, underground mines move towards the unmanned direction of trackless mining.

①The main advantages of underground mining automobile transportation are that

a. Flexible mobility, with a wide range of application, and great production potential. The mining rock of the mining face can be directly transported to each unloading site without midway transfer, and the personnel, materials and equipment in the unloading site can also directly reach the working face without transfer.

b. Under certain conditions, the use of underground mining automobile transportation can appropriately save equipment, steel and personnel.

c. Before the completion of the complete set of shaft facilities, it is possible to advance and facilitate the mining and transportation of ore bodies and sporadic edges.

d. Under the conditions of reasonable transport distance, the underground mining automobile transportation and production links are less, which can significantly improve the labor productivity.

②The disadvantages of underground mining automobile transportation are follows:

a. Although the underground mining cars have an exhaust gas purification device, the exhaust gas discharged from the diesel engine pollutes the underground air, which still cannot be completely solved at present. Measures such as strengthening ventilation are usually used to increase the cost of ventilation equipment.

b. Due to the poor quality of the underground mine road surface, the tire consumption is large, and the cost of spare parts increases.

c. Maintenance workload is large, need skilled maintenance workers and well-equipped maintenance workshop.
d. In order to facilitate the driving of underground mining cars, the required roadway section size is large, which increases the development cost.

③ Compared with ground self-unloading vehicles, underground mining vehicles usually have the following characteristics in structure:

a. Can assemble and assemble, convenient large well.
b. Using articulated chassis, hydraulic steering, the car body width is narrow, the turning radius is small.

c. The car body height is low, generally 2~3m, which is suitable for working in the narrow and low underground space, with a low center of gravity, which increases the climbing ability.

d. The driving speed is low, and its engine power is small, thus reducing the exhaust emissions.


(3) Belt conveyor transportation

Belt conveyor transportation is a continuous mode of transportation, mainly used to transport mineral rock, can also transport materials and personnel. This mode of transportation has large production capacity, safe and reliable, simple operation and high degree of automation. With the use of high strength tape, belt conveyor transportation has the characteristics of long distance, large volume and high speed, which meets the requirements of efficient transportation of modern mining equipment.

The use of belt conveyor transportation in underground ore is limited by the rock mass, traffic volume, roadway inclination, curve and so on. Generally, only coarse crushed ore rock (less than 350mm) can be transported, and only suitable for use with large volume, small roadway inclination, and no curves.

Underground belt conveyor transportation can be divided into: ① stope belt conveyor transportation according to its use place and completed transportation tasks, which directly receives and transports mineral rocks from the mining working face.② Mining collection belt conveyor transportation, which receives mineral rock from two or more belt conveyors.③ Trunk belt conveyor transportation, it carries all the underground mining rock, including the belt conveyor to the surface of the belt conveyor transportation.

Belt conveyor can be divided into basic and special types according to the basic structure, and the basic type is divided into flat and groove shape. At present, the representative special belt conveyor has deep groove belt conveyor, corrugated edge belt conveyor, pattern belt conveyor, tubular belt conveyor, air cushion belt conveyor, pressure belt conveyor, bending belt conveyor and so on.

Belt conveyor transportation realizes the continuity of material transportation process. Compared with other conveying equipment, it has the following characteristics:
①conveying capacity. The maximum capacity of domestic belt conveyor has reached 8400t / h, and the maximum capacity of foreign belt conveyor has reached 37500t / h.
②Long delivery distance. As long as there is enough strong belt, from a technical point of view, the belt conveyor in the transmission distance is not limited. The single length of domestic belt conveyor has reached 15.84km.
③Strong terrain adaptability. The belt conveyor can adapt to the terrain from the moderate curve of space and horizontal plane, so as to reduce the intermediate links such as the transfer station and reduce the infrastructure investment, so as to avoid the interference with roads, railways, mountains, rivers, rivers and cities from the space or plane.
④Simple structure, safe and reliable. The reliability of belt conveyor has been verified by many applications in the industrial field.
⑤Low operating costs. The time hour and energy consumption per unit transport of the belt conveyor system is usually the lowest among all bulk material vehicles or equipment, and the maintenance is easy and quick.
⑥ High degree of automation. Belt conveyor conveying process is simple, power equipment concentration, high control, easy to achieve automation.
⑦ It has the characteristics of low degree of weather influence and long life span.



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Post time: Mar-16-2023