Technologies and conditions for the efficient use of mobile crushers and conveyor belts

Several studies have shown that most mining costs are spent on transporting material. When looking at the cost chain, from drilling and blasting to the storage of large crushed material, transportation is generally 40-60%. So, if you're looking for resources, you can cut costs. The transport process must therefore be carefully analyzed. A comparison of the cost of transporting rocks on the road and in traffic shows that they can save up to 70-80%.

It is well known that the original material of the rock to be conveyed by conveyors is usually milled to the maximum size of a work piece, usually 300 to 400 mm. This demand led in the 1950s to the development of semi-mobile and mobile equipment for large scale crushing. The design of such machines was initially a "solid breaker that was converted to a mobile device", which made them very heavy and difficult to move. In general, these machines have changed installation locations once or twice during one working month.

Since the mid-1980s, the situation in the non-metallic industry has been similar to that in other areas of mining. Almost all major breakers were stationary or mobile in a mobile chassis. In 1985, the world has already seen a new type of mobile tracking device that meets the needs of non-metallic material manufacturers who often transport their equipment on public roads. On this basis, larger and more productive crushers were created to maintain high mobility. These machines move around the plant during the day and open up new possibilities for planning the field development and loading possibilities for the material to be conveyed.

Table of content
1. Production costs.
    1.1 Transport distance.
    1.2. Annual productivity of the company..
    1.3 Environment and job security..
    1.4 Dismantling report.
    1.5 Operational flexibilityt.
    1.6 Line of mobile crushers.
2. Perforation and rays in mass.
     2.1 Load
     2.2 Crusher loading methods
     2.3 Backhoe
     2.4 Wheel loaders
3. Dump Truck
4. Impact on mining planning
5. You can list a few points

1. Production costs

One of the criteria for the evaluation of a transport system is the cost of the end products. Below is a comparison of the cost of transporting products via conveyor belts and vehicles with an analysis of their sensitivity to various operational factors.

1.1 Transport distance

The use of conveyor belts can be used for long distances

On the other hand, the fleet of dump trucks is limited both in terms of minimum and maximum distance of freight traffic, and at short distances it often does not fully exploit the potential of its performance:

- With a delivery distance of 1.0 km, the price difference of one tonne of products is extremely remarkable and the reimbursement will be reached in about 2 years.





- At the time of delivery at a distance of 5 km, the cost of transporting a tonne of freight is even lower than for road transport. Due to the large capital investment, the recovery phase increases at about 15 years.

Since then, the number of mobile crushers in the caterpillar used in the industry has increased. In the production of non-metallic materials, for example, three-stage crushing and sieving complexes are not uncommon.

Rising fuel prices and expensive truck tires have a negative impact on production costs. Properly used, mobile crushing and screening equipment, in combination with the transportation of the conveyor equipment, provide the undeniable advantage of using all equipment.

1.2. Annual productivity of the company.

With increasing annual transport volume, the competitiveness of conveyor belts increases

This can be explained by the fact that relatively little investment in the extension of the transport of conveyors can significantly increase their productivity.  The payback period has been reduced to about 8 years.
The value of the total inclination angle of the transport route.

The steeper the ascent, the greater the advantage of a conveyor system. This is mainly due to a decrease in speed and increased fuel consumption of dump trucks when driving on roads with higher elevation angles. On the other hand, conveyor belts require high performance units to overcome steep climbs. Figure 4 shows the transport costs of 1.0 million tons of iron ore per year over a distance of 5.0 km on the roads with an increase of 8%. Under these conditions, the repayment period is also already shortened in about four years.

1.3 Environment and job security.

Reducing the use of automobiles will still reduce the negative impact of mining on the environment

Trucks are the main cause of harmful effects in the form of exhaust fumes, dust and noise. According to international agreements, the permissible emission levels of diesel engines have been significantly reduced, but the effects are increasing. Replacing lorries with electrically operated conveyors completely eliminates these harmful emissions. For example, the dust generated during the movement of vehicles can be removed with water, however, these measures require expensive equipment and never eliminate the problem. Conversely, conveyor belts with dust protection solve the dust problem.

At the same time, moving the dump truck poses a constant threat to the health of a nearby person. Therefore, road and quarry accidents still occur, regardless of compliance with safety regulations. However, to be fair, it should be kept in mind that conveyor belts that significantly reduce industrial risk do not completely eliminate it.

1.4 Dismantling report

To organize the efficient operation of dump trucks in a quarry, a mountain is much larger than required for the installation and maintenance of conveyor belts. When a sloped deposit is being developed, the sides of the well bore may be exposed to higher angles, thereby reducing the overload coefficient and final excavation volume. In developing some careers, this can have a critical impact on production costs.

1.5 Operational flexibility

Mobile operations are needed because of excavations in different places

Mobile crushers are extremely versatile for two reasons:

• They are the equipment of the standard model range of most manufacturers and as a result the delivery orders will go through fairly quickly.
• You can easily move from one object to another and get up quickly after the next move.

These advantages make these machines ideal for restrained quarries, as they do not interrupt the production process when a fixed or semi-moving shredder is rechecked or moved. They can also be used to grind materials used in the construction of infrastructure, roads, dams and underground cavities.

1.6 Line of mobile crushers.

A mobile rough-grinding installation model

When considering the ability to use and select a mobile rough-grinding installation model, the following factors should be considered:

- Strength and abrasiveness of rocks: determines the type of crusher used;
- The size of the maximum power part: determines the required size of the breaker input;

The grain size composition of the food: determines the proportion of the volume in the feed stream which can be omitted in the first stage mill;

- Required capacity: Determines the type and size of the crusher, the feeder and the unloading conveyor.
- Required product size: determines the type and size of the crusher;
- Type and method of download: Determines the size and design of the receiving bunker.





Impact of complete mobile crushers with conveyor belts in operation and extraction process
The use of transport systems, consisting of mobile mobile crushers and conveyor belts, has a decisive influence on all technological processes and extraction processes.

2. Perforation and rays in mass.

The requirements for additional mineral processing do not depend on the type of crusher used for larger shredding: stationary or mobile. For a mobile crusher as for a stationary crusher, the ratio between the size of the drip hopper and the maximum size of the rock fed to the primary crushing operation is compelling. These proportions are the same for both types of crushers.

2.1 load

Mobile crushers and conveyor belts is particularly effective

Despite the high mobility of the Lokotrack and Lokolink conveyors, every movement is associated with the inevitable technological decommissioning of the entire complex. One of the real ways to reduce the number of movements of the entire complex is to increase the width of the processed input. This method is associated with the need to increase the number of exploding well pipelines. The system of mobile crushers and conveyor belts is particularly effective for the development of large shelves and a large number of wells working simultaneously. This last factor has a particularly important influence on the productivity of the digging machine and the load installed on the face.

2.2 Crusher loading methods

As mentioned above, the relatively high mobility of the Lokotrack and Lokolink systems does not preclude effective work with excavators equipped with implements, such as front loaders and backhoe loaders. In addition, high performance wheel loaders with a bucket can also be effectively used to load coarse grinding crushers.

2.3 Backhoe

Currently, the load is carried on a rail with excavators in most large breakers. Small Models This type of machine is widely used in the industry because it offers obvious advantages in terms of specific productivity calculated per unit of work time for a number of factors:

- Easy control of excessive size in the chuck (because the operator sees the bucket filling process);
- a permanent overview of the grill conveyor, as the shovel is placed on the pile of stones. This helps to maintain the required loading of the grill material.

The size of the excavator can be selected to meet the capacity required to load the crusher.
In most cases, the use of excavators with equipment such as an excavator is considered to ensure the lowest possible loading costs.

When a crawler excavator is moved forward to a crawler excavator, its model is selected according to the working parameters of the machine: bucket capacity, radius and height of the unloading bucket, radio and height excavation. In normal operation, this usually results in the selection of a large bucket. Controlling the size of the crusher material loaded in the bucket and advancing the rock mass to the crusher is not as easy as using a backhoe.

The dredger works best to load the crusher evenly and finely into the hopper. With such packages, an excavator usually develops the best charging performance. The bucket "direct bucket" is at the same level as an excavator in terms of excavation work.

2.4 Wheel loaders

Wheel loaders have their own capacity

The wheel loader is inferior to both types of excavators in terms of the capacity and size of the excavation effort removed, as well as the oversize control of the crushing feed. Due to the ability of the loaders to direct the rocks into the bucket to the crusher silo, the use can increase the displacement capacity of a large crusher that is between 3 and 5 times. Hours 2-3 turns. , whereby the production time of the grinding complex is increased. The wheel loaders can also mix several rock surfaces (in the middle mode), whereby the optimum composition of the feed of the crusher can be achieved, while the maximum conveying distance of the rocks in the bucket of the loader (almost equivalent) is ensured). Crusher transfer) from 75 to 100 m.

When using a shovel loader mounted on the wheel, it is usually necessary to build a sloped ramp to load the standard shredder onto a line equipped with a grate feeder to allow the rock to pass from the bucket of the loader to the receiver unloaded. Funnel A boom of this type is usually cast from crushed rock and for half an hour of work, which is technically quite acceptable given the frequency of breaker movements. Higher productivity of the grinding complex requires the use of a plate loader to reduce the loading height and thus the cycle time of the loader.

3. Dump Truck

Dump truck is a material transport but its capacity is limited

Typically, large standard caterpillar breakers have no receptacles to allow the direct discharge of rocks from the garbage truck. However, the possibility of such work organization can bring some benefits to the technology of mining production, especially at the beginning of a career development. This can occur, for example, when opening a new horizon in a quarry if there is sufficient space for the installation and operation of mobile crushers and conveyor belts.

It may also be technologically justified if the amount of rock mined in isolated parts of the quarry makes it economically impossible to dispose of waste into the quarry's transport system. In such situations, a large standard-way crusher may be fitted with an additional special bunker for the ground that can hold material dumped from the dump truck's trough.

4. Impact on mining planning

Using conveyor belts greatly reduces material transportation costs

The indisputable advantage of road transport in a quarry is, as we know, its technological flexibility, as the original shredded material, with its help, can always be delivered from the sides, which are located somewhere in the mine. Of course this applies as long as there is a network of internal access roads on each side. The transport rate of the landfill of the mountainous mass of the quarry has no significant effect, for example when one or more garbage trucks stop working. These shutdowns can be easily eliminated at the expense of the reserve machines available in the quarry to keep the company's production capacity at least at a certain level.

Coarse shredding systems and conveyor belts are not that flexible. Mobile crushers for coarse crushing and moving conveyor belts are easy to move in the quarry, but the entire quarry transport system prevents a rapid change in the mode of operation of all transports. For this reason, mine planning is probably the only place where the use of coarse sanding systems and belt conveyors appears most critical.

The planning of the gradual progression of each horizon as well as a plan to place multiple sections of the career transport system has been developed over the years. At the same time he tries to minimize the frequency of movement of the conveyor belts.
General considerations on the efficiency of the crusher and the means of transport.

However, if the conditions for developing a particular domain do not meet the above requirements, there are ways to successfully implement the systems under consideration.

5. You can list a few points:

- Combine mobile equipment for large crushing and conveyor belts that work on two or three adjacent strips in a common system.
- The use of two or more parallel systems. This principle makes it possible to mix the starting material with different qualities that are extracted on different surfaces by expanding the theoretical productivity range of the opencast mines and improving the availability factor of the equipment.
- The possibility of uniting the mountain mass coming from camps or different faces through the energy system of the tunnel in one stream.

Recommendations

Mobile shredding systems and conveyor systems are characterized by certain limitations, mainly due to their operational flexibility, compared to transport in dump trucks. In many cases, however, these limitations do not play an important role or can be overcome by professional and innovative mining planning. With a carefully reviewed system application, the costs for mineral extraction can be significantly reduced. Therefore, it is very important for mining companies to determine the possibility of using the system at an early stage of the modernization of existing production or in a completely new project.