On the Operation of Loading Machines and Exchange Devices in the Mines of Kuzbass
Abstract Generated abstract
This paper examines time losses in loading and mine-car exchange during horizontal mine drivage in Kuzbass, where these operations could occupy a large share of the work cycle. Based on observations of UMP-1 and PPM-3 loading machines using turnout switches and portable transfer platforms, the authors relate exchange time to haulage distance, maneuvering time, and mine-car capacity, and compare the effects on machine productivity. The analysis indicates that larger mine cars generally increase loading-machine productivity under the observed exchange methods, although small cars may be preferable where haulage is short and shunting is minimal. The paper derives formulas for estimating cycle loading time and selecting an optimal mine-car capacity, and notes that the advantage of a portable transfer platform over a turnout switch diminishes as haulage distance approaches about 80 m.
Full Text
On the Operation of Loading Machines and Exchange Devices in the Kuzbass Mines
P. V. Akimochkin, V. G. Lukyanov
(Presented by the scientific seminar of the Department of Mining Mechanics of the Mining Faculty)
In driving horizontal workings, the operations of loading and exchanging mine cars take up to 40% of the time of the drivage cycle. Such large expenditures of time on these operations are explained above all by the imperfection of the existing methods of exchanging mine cars and of the loading machines.
Observations of these operations were carried out during the driving of development workings in Kuzbass on UMP-1 and PPM-3 loading machines, and on methods of exchanging mine cars by means of a turnout switch and a PVP-1 portable transfer platform.
In Kuzbass, turnout switches and portable transfer platforms have found the widest application for exchanging mine cars. These methods are equally suitable for loading machines of periodic and continuous action. Exchanging mine cars by means of conveyors provides more continuous loading, but because of the greater saturation of the face with mechanisms and the absence of special conveyor installations, this method has not yet found wide application.
The principal indicators of the mechanisms for driving workings in which observations were made are given in Table 1.
The dependence of the time for exchanging a mine car on the length of the haul-out is expressed by the formula
\[ t_{0}=\frac{l_{gr}+l_{por}}{v_{sr}}+t_{m}, \tag{1} \]
where
\[ \begin{aligned} t_{0} &\text{ — total time for exchanging one mine car, sec;}\\ l_{gr} &\text{ — haul-out length of the loaded mine car, m;}\\ l_{por} &\text{ — haul-out length of the empty mine car, m;}\\ v_{sr} &\text{ — average speed of mine-car movement, m/sec;}\\ t_{m} &\text{ — time of maneuvers at the exchange point, sec.} \end{aligned} \]
The influence of mine-car capacity on the productivity of the loading machine is shown in Figs. 1 and 2.
From the curves in Figs. 1 and 2 it is evident that, as the capacity of the mine car increases, the exchange time increases; consequently, the productivity of the machine should decrease, but in reality the productivity of the machine increases.
Table 1
| Indicators | “Egorovskaya No. 1” | “Polysaevskaya No. 3” | “Ziminka 1–2” | Mine No. 8 |
|---|---|---|---|---|
| Working | main crosscut | water-collection roadway | main crosscut | field drift |
| Mine-car capacity, $m$ | 1 | 2 | 2 | 2 |
| Loading machine | PPM-3 | UMP-1 | UMP-1 | UMP-1 |
| Exchange method | cut-in switch | cut-in switch | cut-in switch | PPP-1 |
| Haulage distance, m | 80 | 85 | 65–70 | 40–50 |
| Time for loading one mine car, sec | 240 | 654 | 630 | 412 |
| Time for hauling the loaded mine car, sec | 55 | 125 | 113 | 109 |
| Time for moving up the empty mine car, sec | 18 | 106 | 173 | — |
| Shunting at the siding | 37 | 24 | 29 | 30 |
| Total for exchange, sec | 110 | 225 | 315 | 139 |
Fig. 1. Dependence of the productivity of the PPM-3 machine on mine-car capacity when using a cut-in switch. 1—one-ton mine car; 2—two-ton mine car.
The productivity of the machine is determined by the formula
\[ P_1=\frac{3600v}{t}=\frac{3600v}{t_n+t_o}, \tag{2} \]
where
\[ \begin{aligned} P_1&\text{— productivity of the loading machine, taking into account the time}\\ &\quad\text{for exchanging mine cars, } m^3/\text{hour};\\ t&\text{— time for loading and exchanging the mine car, sec};\\ v&\text{— mine-car capacity, } m^3;\\ t_n&\text{— time for loading one mine car, sec.} \end{aligned} \]
The productivity of the machine, calculated by formula (2), is shown in Figs. 1 and 2. From the curves in Figs. 1 and 2 it is evident that, with an increase in the capacity of the mine car, for the indicated haulage parameters the productivity of the machine increases.
Taking the complete cycle of loading and exchange as 100%, we find the specific time expenditures for exchanging mine cars at various haulage lengths (Fig. 3). From Fig. 3 it is evident that, as the haulage length increases, both methods of exchanging mine cars of different capacity become identical; and at a haulage length of up to 80–100 m, the exchange of mine cars takes 40–50% of the total time for loading the rock.
Fig. 2. Dependence of the productivity of the UMP-1 machine on mine-car capacity when using the PPN-1. 1—one-ton mine car; 2—two-ton mine car.
It was established above that, with an increase in the capacity of the mine car, the productivity of the loading machine increases. However, it must be noted that, as the capacity of the mine car increases, the time for shunting operations increases and the speed of hauling the mine car decreases; therefore, under certain conditions, when the haulage length is small and the shunting operations involved in exchange are reduced to a minimum, it will be more expedient to use mine cars of small capacity.
This proposition is confirmed by the experience of high-speed drivages. Thus, for example, in Czechoslovakia, when driving a crosscut, a mine car with a capacity of 0.6 m³ was used; in this case all shunting operations, in comparison with 2- and 3-ton mine cars in the Kuzbass, were reduced by a factor of 10 or more.
The optimum mine-car capacity can be determined on the basis of minimum time expenditures by expressing the rock-loading operations through the capacity of the mine car:
\[ T = n\left(t_{p} + \frac{2l}{v_{\mathrm{cp}}} + t_{M}\right), \tag{3} \]
where \(T\) is the total loading time per cycle, h;
\(n\) is the number of mine cars required for unloading the rock from the work cycle;
\(l\) is the haulage length, m.
The number of mine cars required for the work cycle of loading rock is determined from the expression
\[ n = \frac{Q}{v}, \tag{4} \]
where \(Q\) is the volume of rock per cycle in the loosened state, m³.
The time for loading rock is
\[ t_{p} = \frac{v}{P_{T}}, \tag{5} \]
where \(P_T\) is the technical productivity of the machine.
Substituting the values of \(n\) and \(t_n\) into equality 3, we obtain
\[ T=\frac{Q}{v}\left(\frac{v}{P_T}+\frac{2l}{v_{cp}}+t_m\right). \tag{6} \]
From formula (6) we find the value of the mine-car capacity \(v\)
\[ v=\frac{P_T Q(2l+t_m v_{cp})}{v_{cp}(P_T T-Q)}\,\text{m}^3 . \tag{7} \]
The formula obtained can be applied in those cases when the mine cars are supplied to the loading machine continuously.
If the total productivity of the loading machine over a cycle is known, then the last formula can be represented in the following form
\[ v=\frac{\dfrac{2l}{v_{cp}}+t_m}{\dfrac{T}{Q}-\dfrac{1}{P_T}} \tag{8} \]
Replacing \(\dfrac{T}{Q}\) by \(\dfrac{1}{P_1}\), we obtain
\[ v=\frac{P_1P_T\left(\dfrac{2l}{v_{cp}}+t_m\right)}{P_T-P_1}. \tag{9} \]
Fig. 3. Specific share of the time spent on exchanging mine cars. 1—one-ton mine car, UMP-1 machine with PPP-1; 2—two-ton mine car, UMP-1 machine with PPP-1; 3—one-ton mine car, PPM-3 machine with a siding switch; 4—two-ton mine car, PPM-3 machine with a siding switch.
Using the formulas given above, one can calculate the loading time for a specified mine-car capacity or the required mine-car capacity for a specified cycle duration, which is largely determined by the level of mechanization of heading operations.
Conclusions
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Increasing the capacity of the mine car raises the productivity of the loading machine in the case of exchanging mine cars by means of a siding switch or a movable turntable platform.
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With an increase in the haulage length to 80 m, as can be seen from Fig. 3, the advantage of the movable turntable platform over the siding switch is lost.
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It is recommended that the optimal mine-car capacity be determined by formula (8).
Literature
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Kostin N. P., Kutsarov M. I., Alekseevskii N. A., Stadnichenko A. P. Driving a drift at a rate of 302 m/month. Gornyi zhurnal, No. 9, 1956.
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Kukel V. N. Driving a crosscut at a rate of 870 m/month. Gornyi zhurnal, No. 6, 1955.