In the complex system of coal mining and transportation, the coal bunker plays a crucial role. It acts as a key hub, connecting various stages of coal production. Coal mined from the working face is first transported to the coal bunker for temporary storage. Its presence effectively solves the imbalance in transportation capacity between different stages of coal production. Storage provides a buffer for transportation capacity. For example, the output of a high-speed coal cutter often differs from the transportation capacity of subsequent equipment; the coal bunker can play a regulating role. Similarly, during the transition between different transportation methods, such as from intermittent transportation by mine cars to continuous transportation by conveyor belt, the coal bunker can also play a matching and regulating function; it can also solve the problem of coal transfer between different heights. The reasonable determination of coal bunker capacity is directly related to the efficient operation and economic benefits of the entire mining system, therefore, in-depth research is necessary.

Coal Bunker Capacity Calculation

Calculation Based on Coal Mining Capacity

In coal mining operations, the output of a coal cutter continuously cutting a single layer of coal is one of the important bases for determining the capacity of the coal bunker. The calculation formula is:

In this formula, each parameter has a specific meaning and function. Q₀ Represents the amount of coal left to prevent air leakage, usually taking a value of 5 - 10t This amount of coal is reserved mainly to prevent air leakage in the coal bunker, ensuring the stability of the storage environment inside the coal bunker and preventing coal from oxidizing or spontaneously combusting due to air leakage; L Represents the length of the working face, the unit is m The size of the working face length directly affects the output of each coal mining operation. A longer working face can cut more coal during coal cutter operation; M Is the mining height, that is, the height of the coal seam being mined. It is also a key factor in determining the amount of coal mined. The larger the mining height, the greater the amount of coal mined per operation; B Is the cutting depth, the unit is also m m The cutting depth reflects the depth of the coal cutter's cutting into the coal seam each time. The reasonable selection of the cutting depth not only affects the coal mining efficiency but is also closely related to the amount of coal mined; γ Refers to the bulk density of coal, the unit is t/m³ Different types of coal have different bulk densities. This parameter reflects the density characteristics of coal and is an indispensable element in calculating output; C₀ Represents the mining recovery rate, expressed as a percentage. It comprehensively considers the coal loss during the mining process, such as coal loss due to top management and coal wall slices. The higher the recovery rate, the more fully the coal resources are utilized; K₁ Is the coefficient of the same working face, its value is related to the mining method. For fully mechanized mining, K₁ = 1 For ordinary mining, K₁ = 1 + 0.25n Here, n Represents the number of simultaneously mined working faces in the mining area. This coefficient considers the impact of multiple working faces operating simultaneously under different mining methods on the coal bunker capacity. When multiple ordinary mining working faces operate simultaneously, the coal bunker needs to store more coal to meet production needs. Through this formula, the capacity of the coal bunker can be calculated more accurately based on the coal mining capacity to ensure the smooth storage and subsequent transportation of coal during the coal mining process. 200m For example, for a fully mechanized mining working face, 3m working face length 0.8m mining height cutting depth the bulk density of coal is 95% 1.4t/m³ 8t the mining recovery rate is 1 the amount of coal left to prevent air leakage is the number of simultaneously mined working faces is 。

then, according to the formula, the coal bunker capacity can be calculated as

Q = 8 + 200 × 3 × 0.8 × 1.4 × 0.95 × 1 = 636.8t Calculation Based on Main Road Loading Capacity When calculating the coal bunker capacity based on the main road loading capacity, the peak output of the mining area within the train interval time is mainly used as the basis. The calculation formula is: Q = Q₀ + Qh·ti·ad （ 。

Q₀ t 5 - 10t 。 ） is still the amount of coal left to prevent air leakage, the range is t/h Qh represents the peak production capacity of the mining area, the unit is t/h 。 Generally, the peak production capacity of the mining area is 1.5 - 2.0 times the average output. This is because, during production, there are some special periods, such as when the equipment is running well and the workers are skilled, the output of the mining area will be higher than the average level. ti refers to the interval time for trains to enter the loading station, usually 20 - 30min 1.15 - 1.2 ，炮采取 1.5 This coefficient considers the imbalance in the coal mining process. For example, during blasting operations, coal output may fluctuate significantly at different times due to the impact of blasting operations, so the imbalance coefficient for blasting is relatively high. 。Assuming a certain mechanized mining area, the amount of coal left for preventing air leakage is 6t ，the peak production capacity of the mining area is 300t/h ，the interval time for trains entering the loading station is 25min

 

Calculated according to the peak capacity of the mining area

This calculation method mainly focuses on the duration of peak production in the mining area, and the formula is: Q = Q₀ + (Qh - Q)thc·ad When calculating the coal bunker capacity based on the main road loading capacity, the peak output of the mining area within the train interval time is mainly used as the basis. The calculation formula is: Q = Q₀ + Qh·ti·ad （ ，it is mainly used for ） ＞ Q situations, the purpose is to ensure continuous production in the mining area.

Q₀ or the amount of coal left for preventing air leakage, between 5 - 10t and 。 ） represents the peak production capacity of the mining area, t/h ，generally (1.5 - 2.0)Ap When calculating the coal bunker capacity based on the main road loading capacity, the peak output of the mining area within the train interval time is mainly used as the basis. The calculation formula is: Ap (average output) 。 Q represents the throughput capacity of the mining area loading station, the unit is t/h ，it reflects the amount of coal that the loading station can handle per unit of time； thc is the duration of peak production in the mining area, for mechanized mining it is 1 - 1.5h ，for blasting mining it is 1.5 - 2.0h ，this time reflects the duration that the mining area can sustain in a peak production state. The longer the duration, the more coal needs to be stored in the coal bin； refers to the interval time for trains to enter the loading station, usually Similarly, it is the imbalance coefficient, the value for mechanized mining is 1.15 - 1.2 ，for blasting mining it is 1.5 。For example, in a certain mechanized mining area, the amount of coal left for preventing air leakage is 7t ，the peak production capacity of the mining area is 250t/h ，the throughput capacity of the mining area loading station is 200t/h ，the duration of peak production in the mining area is 1.2h ，the imbalance coefficient is 1.15 ，the coal bin capacity can be obtained through calculation using the formula Q = 7 + (250 - 200) × 1.2 × 1.15 = 76t 。When the mining area is ( below ) When both the mountain and the main roadway use belt conveyors for coal transportation, the coal bin capacity in the mining area should be no less than 1 - 2h peak production of the mining area is determined. In this case, the determination of the coal bin capacity is relatively simple and direct, and only needs to be calculated according to the peak production and time of the mining area. 。

Factors Affecting Coal Bin Capacity

Mining Area Production Capacity

Mining area production capacity is one of the core factors affecting coal bin capacity. When the mining area production capacity is large, the amount of coal produced per unit of time will increase. For example, compared to a small mining area with a daily output of thousands of tons, a large mining area with a daily output of tens of thousands of tons will produce a large amount of coal in a short period of time. If the coal bin capacity is too small, it will not be able to store this coal in time, causing the coal mining working face to have to suspend production and wait for the coal bin to have enough space to store coal. This not only reduces coal mining efficiency but may also cause unnecessary wear and tear on equipment. Conversely, if the mining area production capacity is small and the coal bin capacity is too large, it will cause resource waste and increase construction and maintenance costs. In actual production, with the continuous advancement of mining technology, some mining areas have significantly improved their production capacity by adopting more advanced coal mining equipment and processes. This requires re-evaluating and adjusting the coal bin capacity to meet new production needs. For example, a certain mining area originally used ordinary coal mining equipment with a production capacity of  100t ，and the matching coal bin capacity is 500t 。Later, the mining area introduced advanced fully mechanized mining equipment, and the production capacity increased to 200t ，the original coal bin capacity could not meet the production needs. After recalculation, the coal bin capacity was expanded to 1000t ，to ensure the smooth progress of production. 。

Loading Station and Main Roadway Transportation Capacity

The throughput capacity of the loading station is directly related to the output speed of coal in the coal bin. If the throughput capacity of the loading station is low and cannot timely load and transport the coal in the coal bin, the coal bin will quickly be filled, limiting the continuous progress of coal mining work. For example, some old loading stations have aging equipment and cumbersome operation processes, and can only load  50t of coal per hour, while the coal inflow speed of the mining area coal bin is 80t ，then the coal bin will quickly be filled, and the coal mining work will have to be interrupted. The main roadway transportation capacity is equally crucial, determining the efficiency of coal transportation from the loading station. When the main roadway transportation capacity is insufficient, even if the loading station can quickly load coal, it cannot be transported away in time, and the coal bin will still face the problem of backlog. Main roadways using small mine cars have limited transportation capacity, and after the mining area production capacity is improved, coal will accumulate in the coal bin. Only when the throughput capacity of the loading station and the main roadway transportation capacity match the production capacity of the mining area can a reasonable coal bin capacity be determined to ensure the efficient operation of the entire coal transportation system. For example, a certain mining area loading station can load 150t of coal per hour, and the main roadway transportation capacity is 180t ，the peak production capacity of the mining area is 200t After calculation, the coal bin capacity is determined to be 800t In this case, even during peak production periods in the mining area, smooth storage and transportation of coal can be ensured 。

The relationship between coal bin capacity and mining efficiency

Ensuring continuous production

In mining operations, appropriate coal bin capacity is a key factor in ensuring continuous production. The coal output process of the coal face is not uniformly stable and is affected by various factors such as equipment operating conditions and changes in geological conditions. For example, when the coal cutter encounters complex geological conditions such as coal seam faults and roof breakage, the coal mining efficiency will decrease, but in areas with good geological conditions, the coal cutter can operate at high speed and produce a large amount of coal in a short time. If the coal bin capacity is too small, once the coal cutter is in a high-yield state, the coal bin will quickly be filled, and there will be nowhere to store the subsequently mined coal, so the coal face will have to stop work and wait for the coal bin to free up space, which will lead to production interruption. However, when the coal bin capacity is large enough, even during periods of high coal cutter output, a large amount of coal can be accommodated, and the coal face can continue to operate, ensuring the continuity of coal mining. Similarly, in the coal transportation link, transportation equipment may also experience failures or maintenance, causing temporary interruptions in transportation. If there is a coal bin with sufficient capacity at this time, the coal mined from the coal face can be temporarily stored to avoid the cessation of coal mining due to transportation interruptions, ensuring the smooth progress of the entire mining operation process.

Improve equipment utilization

Sufficient coal bin capacity has a significant effect on improving the utilization rate of mining and excavation equipment and transportation systems. For mining and excavation equipment, when the coal bin capacity is sufficient, coal cutters, roadheaders, and other equipment can operate at their optimal working rhythm without having to frequently stop and wait due to a full coal bin. Taking the coal cutter as an example, frequent starting and stopping during operation will not only reduce coal mining efficiency but also increase equipment wear and energy consumption. With a coal bin of appropriate capacity, the coal cutter can continuously mine coal, reducing unnecessary downtime, thereby increasing equipment working time and coal mining volume, and thus improving the utilization rate of mining and excavation equipment. From the perspective of the transportation system, the coal bin can play a role in regulating the transportation volume. When a certain link in the transportation system has insufficient transportation capacity, the coal bin can store excess coal to prevent coal from accumulating at the mining and excavation face and affecting the normal operation of mining and excavation equipment. For example, the number of mine cars for main roadway transportation is limited. During peak coal production periods, it is impossible to transport all the coal in time. In this case, the coal bin can store some coal, allowing mining and excavation equipment to continue working. After the transportation system restores its normal transportation capacity, the coal in the coal bin is then transported out, ensuring the stable operation of the transportation system and improving the utilization rate of transportation equipment. In addition, reasonable coal bin capacity can also enable better coordination between different transportation links, reducing equipment downtime due to transportation mismatches, and further improving the efficiency of the entire transportation system.

Case analysis of coal bin capacity design

Taking a certain modern large-scale coal mine as an example, this coal mine uses a fully mechanized mining technology and has a high production capacity. When designing the coal bin capacity, the calculation is first based on the coal mining capacity. The length of its coal face is L 为 250m For example, for a fully mechanized mining working face, M 为 3.5m working face length B 为 0.7m The bulk density of coal is The cutting depth reflects the depth of the coal cutter's cutting into the coal seam each time. The reasonable selection of the cutting depth not only affects the coal mining efficiency but is also closely related to the amount of coal mined; 为 1.35t/m³ The extraction rate of the coal face is Different types of coal have different bulk densities. This parameter reflects the density characteristics of coal and is an indispensable element in calculating output; 为 96% The amount of coal left for preventing air leakage is Q₀ Take 8t The number of simultaneously mined working faces is Here, 为 1 (Because fully mechanized mining is used, the coefficient of simultaneously mined working faces is Is the coefficient of the same working face, its value is related to the mining method. For fully mechanized mining, （ According to the formula Q = Q₀ + LMBγC₀K₁n The calculation yields Q = 8 + 250×3.5×0.7×1.35×0.96×1 = 835.7t 。

 

When calculating according to the peak capacity of the mining area, the peak production capacity of the mining area is ） 为 400t/h The throughput capacity of the mining area loading station is Q 为 300t/h The duration of peak production in the mining area is thc 为 1.3h The unevenness coefficient is refers to the interval time for trains to enter the loading station, usually Take 1.15 The amount of coal left for preventing air leakage is Q₀ 为 8t According to the formula Q = Q₀ + (Qh - Q)thc·ad The calculation yields Q = 8 + (400 - 300)×1.3×1.15 = 157.5t 。

Considering the three calculation methods comprehensively and combining the actual production situation and development plan of the coal mine, the coal bin capacity is finally determined to be 800t In actual operation, this coal bin effectively ensured the continuous production of the coal face. During periods of high coal cutter output, the coal bin can store excess coal, avoiding coal cutter downtime due to a full coal bin; at the same time, when the transportation system experiences a temporary failure, the coal in the coal bin can also ensure the smooth progress of subsequent production, ensuring the efficient and stable operation of the entire coal mine production system, and improving coal production efficiency and economic benefits This case shows that when designing the coal bin capacity, multiple calculation methods need to be used comprehensively, and various practical factors need to be fully considered to determine the coal bin capacity most suitable for coal mine production 。

Summary

The determination of coal bin capacity is a complex and crucial process, closely related to various aspects of mining operations. From the perspective of calculation methods, calculation based on coal mining capacity can accurately grasp the demand for coal bin capacity from the single coal cutting output in mining operations; calculation based on main roadway loading capacity can determine the capacity required by the coal bin under the operating rhythm of the loading station based on the actual situation of main roadway transportation; calculation based on peak capacity of the mining area focuses on the special situation of the mining area during peak production periods to ensure the continuity of production. These calculation methods complement each other and provide a scientific basis for determining a reasonable coal bin capacity. Many factors affect coal bin capacity, with the production capacity of the mining area being the dominant factor, and its size directly determines the amount of coal that needs to be stored in the coal bin; the loading station and main roadway transportation capacity affect the determination of coal bin capacity from the perspective of coal output. Only when the three are matched can efficient coordination between coal production and transportation be achieved. Reasonable coal bin capacity has a great effect on improving mining efficiency. It can not only ensure the continuous operation of mining operations and avoid production interruptions due to poor coal storage and transportation, but also improve the utilization rate of mining and excavation equipment and transportation systems, reduce equipment idleness and wear and tear, and reduce production costs.