On the Methodology for Calculating the Productivity of Support Installers
Abstract Generated abstract
The paper develops a methodology for calculating the hourly and shift productivity of powered support handlers used in driving mine workings with continuous prefabricated reinforced-concrete supports. Using operating data from the UT-1 tubbing handler at the Chertinskaya-Zapadnaya mine, it decomposes the installation cycle into machine operations, preparatory and concluding work, technological interruptions, and rest, and derives formulas that account for both per-element and per-shift unproductive time. The analysis indicates that productivity is strongly affected by the number and duration of auxiliary operations, while increasing element lifting speed alone is not decisive under the examined conditions. The paper concludes that support-handler design should be coordinated with simpler support designs and less operation-intensive erection processes.
Full Text
PROCEEDINGS
OF THE TOMSK POLYTECHNIC INSTITUTE
OF THE ORDER OF THE OCTOBER REVOLUTION
AND THE ORDER OF THE RED BANNER OF LABOR
NAMED AFTER S. M. KIROV
Volume 177 1971
ON THE METHODOLOGY FOR CALCULATING THE PRODUCTIVITY OF POWERED SUPPORT HANDLERS
V. G. Lukyanov
(Presented by the scientific seminar of the Department of Safety Engineering and Mining Technology)
The creation of a large number of support-handling machines and the widespread introduction of prefabricated reinforced-concrete supports raise the question of the need to develop a methodology for calculating the productivity of a support handler. This will make it possible to resolve correctly, from a technical standpoint, the technological issues involved in driving mine workings.
At present, owing to the great variety of support designs, a large number of support handlers with different design solutions have been created. There are support handlers with element-by-element and with integrated installation of the support. This condition predetermines the procedure for calculating the productivity of a support handler. Let us consider the case of supporting a working with continuous reinforced-concrete support, with the support erected from individual elements. The complete operating cycle of a support handler is the installation of one frame or arch of support. In turn, the working cycle of tubbing handlers with a boom-type working member consists of the consecutive performance of the following principal operations: fastening the tubbings on the gripping device, raising the tubbings and transporting them to the installation site, installing the tubbings, bolting the tubbings together, wedging the tubbings, and lowering the boom to its initial position. These operations may be carried out in time either consecutively or with some of them combined. This is described in detail in the literature [1].
On the basis of operating experience with the UT-1 support handler at the Chertinskaya-Zapadnaya mine of the Leninskshakhtostroi trust, Kuzbass, in installing tubbing support designed by the KuzNIIshakhtostroi Institute, Table 1 was compiled for the balance of working time involved in installing more than one hundred tubbings.
The machine operation of the UT-1 support handler in installing one tubbing consists of several operations, given in Table 2, with the expenditures of machine time for these operations.
The hourly productivity of the support handler \(P_{\text{hour}}\) with continuous reinforced-concrete support will be:
\[ P_{\text{hour}} = \frac{60 l}{t_{\text{c}}}\ \text{m/hour}, \]
where
\(l\) — width of the support element, m;
\(t_{\text{c}}\) — total time for erecting a frame or arch, min.
The total time consists of time spent on: preparatory and concluding work, machine work, technological interruptions, and rest.
Table 1
| Name of expenditure | Expenditures, machine-min | Expenditures per unit of volume, % | Expenditures per unit of volume, machine-min |
|---|---|---|---|
| Preparatory and concluding work | 98 | 2.6 | 0.78 |
| Machine work | 1937 | 90.0 | 26.80 |
| Total useful work | 2035 | 92.6 | 27.58 |
| Technological interruptions | 170 | 4.6 | 1.36 |
| Rest | 104 | 2.8 | 0.84 |
| Total necessary expenditures | 2309 | 100.0 | 29.78 |
Table
| Name of operation | Time expenditures, machine-min: for the entire volume | Time expenditures, machine-min: per one tubbing |
|---|---|---|
| Fastening the tubbings on the machine | 246 | 2.49 |
| Lifting the tubbings and transporting them to the installation site | 182 | 1.89 |
| Installing the tubbings | 658 | 7.39 |
| Bolting the tubbings | 723 | 7.69 |
| Cementing the joints | 56 | 2.54 |
| Wedging the joints | 72 | 4.80 |
| Total . . . | 1937 | 26.80 |
Technological interruptions include such things as: passage of the load into the face, interruptions during blasting and ventilation, and checking the correctness of the installation of the tubbings according to the marks.
The time for installing the support frame is equal to
\[ t_{\mathrm{c}} = (t_1 + t_2 + t_3 + t_4 + t_5)n, \]
where
\(t_1\) — time for fastening the tubbings to the machine, min;
\(t_2\) — lifting the tubbings and transporting them to the installation site, min;
\(t_3\) — installation of the tubbings, min;
\(t_4\) — bolting the tubbings, min;
\(t_5\) — cementing and wedging the joints, min;
\(n\) — number of support elements in the frame or arch.
\[ t_2 = \frac{h_{\mathrm{cp}}}{v_1} + \frac{l_1}{v_2}, \]
where:
\(h_{\mathrm{cp}}\) — average lifting height of the elements, m;
\(l_1\) — average length of transport of the support elements by the support erector, m;
\(v_1\) — lifting speed of the support element, m/min;
\(v_2\) — speed of movement of the support erector along the working, m/min.
\[ t_4 = \frac{k \cdot t_{\mathrm{б}}}{m}, \]
where: \(\kappa\) is the number of bolts per one tubbing, pcs.;
\(t_b\) is the time for installing one bolt, min.;
\(m\) is the number of people engaged in this operation.
Then the hourly productivity of the support handler is expressed by the formula:
\[ P_{\text{hour}}= \frac{60\,l} {\left(t_1+\frac{h_{\text{av}}}{v_1}+\frac{l_1}{v_2}+t_3+\frac{\kappa t_b}{m}+t_5\right)n} \ \text{m/hour}. \]
To determine the shift productivity, it is necessary to take into account all time expenditures for installing the support.
In addition to machine operation, during the shift time expenditures are required for preparatory and concluding work \(t_{\text{p.c.}}\), technological breaks \(t_{\text{t.b.}}\), and rest \(t_o\), given in Table 1.
Fig. 1. Dependence of the productivity of the UT-1 support handler on the lifting speed of the element
In calculating shift productivity, two variants may be encountered. The above time expenditures may be assigned to a unit volume of work \((t'_{\text{p.c.}};\ t'_{\text{t.b.}};\ t'_o)\) or to a shift \((t_{\text{p.c.}},\ t_{\text{t.b.}},\ t_o)\).
Depending on this, the shift productivity of the support handler is determined by the formula:
a) with unproductive time expenditures assigned to a unit volume of work (element),
\[ P_{\text{sh}}= \frac{60\,l\cdot t_{\text{sh}}} {t_c+n\left(t'_{\text{p.c.}}+t'_{\text{t.b.}}+t'_o\right)} \ \text{m/shift}, \]
\[ P_{\text{sh}}= \frac{60\,l\cdot t_{\text{sh}}} {\left(t_1+\frac{h_{\text{av}}}{v_1}+\frac{l_1}{v_2}+t_3+\frac{\kappa\cdot t_b}{m}+t_5+t'_{\text{p.c.}}+t'_{\text{t.b.}}+t'_o\right)n} \ \text{m/shift}; \]
b) with unproductive time expenditures assigned to the shift,
\[ P_{\text{sh}}= \frac{60\,l\left[t_{\text{sh}}-\left(t_{\text{p.c.}}+t_{\text{t.b.}}+t_o\right)\right]} {\left(t_1+\frac{h_{\text{av}}}{v_1}+\frac{l_1}{v_2}+t_3+\frac{\kappa\cdot t_b}{m}+t_5\right)n} \ \text{m/shift}, \]
where \(t_{\text{sh}}\) is the duration of the shift, hours.
The work of support handlers is in most cases multi-operation work, and the auxiliary operations have a relatively large share. Therefore, along with the requirements put forward for the design of support handlers, it is necessary to improve the designs of the support in the direction of simplicity of their installation.
In designing a support handler, great attention is paid to the speed with which the element is lifted by the working member. With existing support designs and the technology for erecting them, this parameter is not decisive, as is confirmed by the graph.
For the specific operating conditions of the UT-1 tubbing handler, Fig. 1 shows the dependence of shift productivity on the lifting speed of the element.
The graph was constructed on the basis of the data in Tables 1 and 2, using the formula for the shift productivity of the support handler.
From the analysis presented, it is clear that when designing such support handlers—and especially handlers for precast reinforced-concrete support—it is necessary to give great attention to achieving a process with few operations for erecting the support. In this case, improving the technical parameters of the support handler will have a significant effect on increasing its productivity.
REFERENCES
- V. G. Luk’yanov, L. K. Dronov. Experience in operating the UT-1 tubbing handler at the Chertinskaya-Zapadnaya mine. Bulletin of TsITIuglya, Scientific and Technical Information, No. 8, 1959.