Available via license: CC BY 3.0
Content may be subject to copyright.
IOP Conference Series: Materials Science and Engineering
PAPER • OPEN ACCESS
Adapting standard maintenance approaches for mining excavators to
actual operating condition
To cite this article: D A Shibanov et al 2020 IOP Conf. Ser.: Mater. Sci. Eng. 966 012138
View the article online for updates and enhancements.
This content was downloaded from IP address 2.56.19.120 on 10/12/2020 at 06:55
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution
of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Published under licence by IOP Publishing Ltd
15th International Conference on Industrial Manufacturing and Metallurgy
IOP Conf. Series: Materials Science and Engineering 966 (2020) 012138
IOP Publishing
doi:10.1088/1757-899X/966/1/012138
1
Adapting standard maintenance approaches for mining
excavators to actual operating condition
D A Shibanov1, 3, S L Ivanov2, K A Safronchuk2 and V I Knyazkina2
1IZ-КАRTEX named after P G Korobkov Ltd., street Brat'ev Radchenko, Kolpino,
Saint Petersburg, 196653, Russia
2Saint Petersburg Mining University, 2, 21 linija, Vasil'evskijostrov, Saint Petersburg,
199106, Russia
E-mail: 3 dan11l88@yandex.ru
Abstract. Significant portion of the annual calendar fund-time work of mining excavators
spent on maintaining its working condition by carrying out preventive and repair regulatory
activities and recovery in the event of emergency failures and maintenance and repair expenses
constitute a significant proportion of the cost of excavation of mining rock. To assess the
effectiveness of machinery a non-standard indicator, the coefficient of technical readiness,
applied which does not have a single assessment methodology. At the present stage of
machinery development, existing quarry dispatching systems allow you to allocate any of its
elements from the fund-time of mining excavators: productive time, time spent in repair and
maintenance and also classify other time costs of a particular machine which allowed an
appropriate analysis. Analysis showed that at the current organization of MaR (maintenance
and repair) there is significant potential to reduce repair impacts, as well as to ensure a
reduction in the cost of routine maintenance, to remove maintenance and repair measures from
the category of costly ones, at least for self-sufficiency without compromising the quality of
these works and the reliability of the excavator as a whole.
1. Introduction
A large part of the annual calendar fund-time work of excavators involved in the extraction of
minerals falls on downtime due to repairs, and the costs of maintenance and repair make up a
significant proportion of the cost of excavating the mining rock.
The effectiveness of the use of equipment according to the criterion of its operability in most
mining enterprises is estimated by the coefficient of technical readiness (Ctr) [1, 2]. In general, Ctr
characterizes the technical level and reliability level of the facility, allowing you to compare the same
type of mining equipment within the same mining enterprise.
Mining enterprises distinguish between planned and actual [3] coefficient of technical readiness,
which are defined as the ratio of the difference between the calendar fund-time work of the planning
period and the time of repair downtime (planned and actual respectively) to the calendar fund-time
work of the planning.
Term ‘coefficient of technical readiness’ is often used in assessing mutual settlements between the
Customer (operating organization) and the Manufacturer (in the particular case, supplier) of new
equipment. When purchasing new equipment, the Supplier and the Consumer jointly determine the
average value of the Ctr specified in the contract, which is guaranteed by the Supplier [4, 5]. Usually,
during the warranty period, the coefficient of technical readiness of mining excavators is 0.80–0.88Ctr
15th International Conference on Industrial Manufacturing and Metallurgy
IOP Conf. Series: Materials Science and Engineering 966 (2020) 012138
IOP Publishing
doi:10.1088/1757-899X/966/1/012138
2
is also used to evaluate the effectiveness of the technical service when the repair units are outsourced
or branded technical service.
The coefficient of technical readiness is not regulated by SSS (State Standard System) and is
subjective in nature. So on some MPPs ((mining and processing plant) (cuts)), work on changing the
teeth of the bucket and ropes is not included in the category of technical downtime affecting the Ctr,
because they are classified as technological, while in other enterprises, these operations are included in
the assessment of this coefficient.
It is often difficult to evaluate and qualify downtime due to the lack of clear objective criteria for
accounting for certain categories of unproductive working hours.
Existing quarry dispatching systems make it possible to allocate productive operating time, time
spent on repair and maintenance from the fund – time of mining excavators, as well as classify other
time costs of a particular machine. The Modular System [6, 7] is used in most enterprises conducting
open pit mining. The operating time data entering this system is largely dependent on the ‘operator’
entering the values into the system. In relation to the excavator, the operator is the driver-operator,
who in the process of work must record all the downtime of the excavator by entering into the
computer information about the operation of the equipment at a particular moment in time (loading,
cleaning the sole, failure, waiting for the dump truck, etc.) [8].
2. Methodology for assessing the coefficient of technical readiness
The coefficient of technical readiness, as in equation (1), is defined as the ratio of the difference
between the calendar fund - time and the actual time of repair downtime to the calendar fund - time of
the estimated period:
(1)
where Ctr is the coefficient of technical readiness, is the calendar fund –time,
is the actual
downtime of the excavator in repairs and waiting for repairs.
The main difference in the evaluation methods of Ctr is the determination of the time for repair
work, specifically the accounting of downtime associated with the replacement of consumables (teeth
and bucket protection, ropes, lubrication and its replacement), since they cannot be clearly regulated
and to a large extent depend on the conditions and operating modes of the mining machine.
At one of the iron ore plants in Russia (hereinafter referred to as MPP), field observations of the
operation of mining excavators of large unit capacity were carried out. The observations were carried
out during the calendar year for two excavators with a bucket volume of 20 m3 [9, 10, 4], in this article
designated as ECG №1 and ECG №2.
The Ctr calculation methodology used at MPP takes into account the time it takes to replace
consumables. Thus, with the consistent performance of all scheduled maintenance recommended by
the manufacturer according to the standards of frequency and duration, the maximum achievable Ctr,
as in equation (2) and (3), per month in the absence of emergency repairs cannot exceed:
(2)
(3)
where TMrep, TMm, TMel.m – time for maintenance of replaceable, monthly, electrical machines,
respectively; Tl.r, Tpr.r, Tret.r, Tteeth – time to carry out work on the replacement of lifting ropes, pressure
ropes, return ropes, bucket teeth, hours.
The frequency of replacement of consumables (ropes, teeth) was taken according to their actual
consumption for the period of the experiment, the regulatory frequency and duration of work was
adopted in accordance with the operating manual for these excavators.
In practice, the activities of mining enterprises and service companies to reduce the time for
maintenance and repair, certain types of work are combined, for example:
15th International Conference on Industrial Manufacturing and Metallurgy
IOP Conf. Series: Materials Science and Engineering 966 (2020) 012138
IOP Publishing
doi:10.1088/1757-899X/966/1/012138
3
1. Shift maintenance is carried out during the reception/change of the shift or at other
organizational and technological breaks (when replacing teeth, ropes, waiting for vehicles), in
particular it must be combined with other types of maintenance work.
2. Monthly maintenance of the electrical part is carried out in parallel with the monthly
maintenance of the mechanical part.
Thus, Ctr in the case under consideration can be increased to the level of, as: in equations (4) and
(5):
, (4)
(5)
3. Analysis of emergency failures of units and parts of excavators ECG №1 and ECG №2
During the operation of excavators ECG №1 and ECG №2, the most significant downtime was due to
an emergency failure, both due to the fault of the manufacturer (factory defects of components and
parts, these cases during the experiment are confirmed by bilateral acts) and a number of disputed
cases are noted on the following units: ropes; pressure axis; handle; idler wheels; cast parts; drive unit.
The total time to restore and wait for repairs on the indicated units for two ECG machines №1 and
ECG №2 amounted to 1054 hours out of 12384 hours of the calendar time-fund (CTF). Thus, the
average time of emergency downtime at the above units is about 65 hours per month (table 1), and the
average Ctr for the specified period was 0.75.
Table 1. Time for troubleshooting individual units and parts.
Unit name
Average
troubleshooting
time, h/month
The share of
emergency
downtime, % CTF
Notes
Pressure axis
27.7
3.85
Redesigned. Axes are in stock
Drive unit
10.6
1.48
Ultrasonic inspection of shafts and gears
introduced
Handle
10.4
1.45
Structural reinforcements on operating machines
have been performed. On the next issued ECG -
the handle of a new design. Additional control
introduced (X-ray, MTD)
Ropes
(pressure,
return, lift)
8.4
1.16
Changed suspension design. Recommendations on
the use of rope d 60.5mm
Idler wheels
4.1
0.57
The lubrication system has been changed, and
input quality control of the supplied bronze has
been strengthened.
Casting defect
no data
0.50
Input quality strengthened.
TOTAL
≈65
9.0
There is no doubt that the operation of mining equipment is impossible without emergency failures
[11–13]. In practice, the work of mining enterprises of the Russian Federation for unplanned work to
eliminate emergency failures lay about 24–27 hours a month, which is 3.3–3.8% of CTF.
For the analyzed period, emergency repairs of the above-described units of the ECG №1
excavators; ECG №2 excavators amounted to 9% of CTF. Of these, a large proportion (42%) was
occupied by emergency breakdowns of the pressure axis, the causes of which are controversial [14,
15]. For the convenience of service, improving the quality of this service, mechanizing production and
reducing economic costs during maintenance and repair of mining machines involved in carrying out
15th International Conference on Industrial Manufacturing and Metallurgy
IOP Conf. Series: Materials Science and Engineering 966 (2020) 012138
IOP Publishing
doi:10.1088/1757-899X/966/1/012138
4
basic and auxiliary works in the implementation of mining technologies, work is underway to create
mobile and autonomous technical means for carrying out delivery work, storage, regeneration and
collection of used oils and lubricants as part of scheduled maintenance and repair work. However,
when performing lubricating and filling operations with the help of mobile workshops, problems arise
associated with forcing grease into the system due to the inability to create the necessary pressure with
domestic metering pumps [16, 17].
Thus, the high share of emergency downtime (9%) after making changes to the design of
excavators, including the use of on-board diagnostic systems and the transition to centralized
lubrication systems with the solution of their refueling problems [18], tends to decrease. It is planned
that according to the results of all warranty work to improve the design of excavators, the share of
emergency failures will be within acceptable limits (3.3–3.8%). Based on the foregoing, in eliminating
the causes of emergency failures, the average Ctr of excavators will be about, as in equation (6):
(6)
After eliminating the accident rate of the listed units, the potential for increasing Ctr by the factor
‘manufacturer’ will be exhausted. Therefore, to achieve the planned Ctr = 0.85 and above, eliminating
the accident rate of the nodes is not enough.
With the elimination of accidents and bringing the duration of repairs to standard indicators, it is
possible to achieve Ctr at the level of, as in equation (7):
(7)
4. Analysis of the time spent on maintenance and repair of excavators
Based on the statistical data of the work of excavators ECG №1 and ECG №2, Table 2 shows a
comparison of the actual and achieved time spent on maintenance and repair, as well as the planned
indicators of the repair department of the MPP (table 2).
Table 2. Comparison of the average planned, actual and achieved time
spent on maintenance and repair of the excavator from 1 January to 30 April.
Type of repair
Duration of repairs per month, h
Deviation of actual time from standard
Actual
GOK
plan
Service company
standard
Time, h
% CTF
Shift maintenance (not
taken into account in
amount per month)
No
data
30
30
–
–
Monthly Maintenance
61
24
24
+37
+5.1
Monthly Electric
Maintenance
12
12
12
0
0
Consumables replacement work
Teeth replacement
24.4
16
16
12
+11.5
+11.5
+11.5
+1.6
Protection replacement
1.1
2
Lift rope replacement
17
12
8
+9
+1.3
Pressure rope replacement
18
12
8
+10
+1.4
Return rope replacement
3
6
4
–1
–0.1
TOTAL
136
82
70
+66.5
+9.2
15th International Conference on Industrial Manufacturing and Metallurgy
IOP Conf. Series: Materials Science and Engineering 966 (2020) 012138
IOP Publishing
doi:10.1088/1757-899X/966/1/012138
5
In order to increase the operating time of the bucket teeth, to reduce the time for their replacement,
as well as to exclude cases of emergency tooth breakages, it is recommended to use teeth tested by the
manufacturer on excavators ECG № 1 and ECG № 2. During the experiment, MPP used bucket teeth
that did not correspond to the design documentation. The result is a decrease in Ctr.
Conclusions
1. The average actual time for maintenance and repair of excavators ECG №1 and ECG №2 is 136
hours per month compared to 82 hours according to the plan of the MPP repair unit. At the same time,
the service company achieved the duration of repair operations – 70 hours per month.
2. When performing maintenance and repair work on excavators, there is the potential to reduce the
repair time by 66.5 hours per month, which is equivalent to an increase in Ctr by 9.2 points.
Thus, subject to the regulatory deadlines, a reserve of time is provided for unplanned and
emergency repairs to repair the excavator.
References
[1] Velikanov V S 2018 Development of the scientific-methodological basis for the career
excavator’s improvement on the basis of an indistinct - multiple approach (Magnitogorsk:
Magnitogorsk State Technical University named after G I Nosov) p 217
[2] Emelyanov A A, Ivanov S L and Shibanov D A 2017 To a question of the operator qualification
influence estimation on the excavator technical condition Open mining works in the XXI
century: results, problems and prospects of development-2. Materials of III International
scientific-practical conference (Mining information-analytical bulletin) Special issue no 38
pp 442–53
[3] Ivanova P V, Ivanov S L, Kuvshinkin S Yu and Shibanov D A 2015 Selection of the rational
system of organization of maintenance service and repair of the quarry excavators for the
given mining engineering conditions Innovations on transport and in mechanical
engineering: Proc. of III international scientific-practical conference. V.II. (SPb: National
mineral university ʻGornyʼ) pp 94–8
[4] Ganin A R, Donchenko T V and Shibanov D.A 2015 Development of a number of the
excavators of 20-25 cubic meters class produced by IZ-KARTEX for mining industry Coal
no 8 pp 79–81
[5] Anistratov K, Donchenko T and Shibanov D 2018 Digging up potential World Coal vol 27 no 7
pp 45–7
[6] Trifanov M G and Shishlyannikov D I 2015 Objective control means as an instrument to
increase the efficiency of operation of the road heading and cleaning combines of the potash
mines Innovations in transport and machine building: collection of III International
scientific-practical conf.; St. Petersburg, 14-15 April 2015 (St. Petersburg: The Russian
Academy Of Sciences) pp 106–108
[7] Brodny J, Stecula K, Tutak M 2016 Application of the TPM strategy to analyze the
effectiveness of using a set of mining machines 16th Int. Multidisciplinary Scientific Geo
Conference pp 65-72 doi: 10.5593/SGEM 2016B12/S03.009
[8] Shibanov D A 2015 Comprehensive assessment of factors that determine the operating time of
EKG-18R/20K excavators for planning maintenance and repairs (St. Petersburg: Mining
University) pp 201
[9] Poderni R Yu 2013 Analysis of the state-of the art of the surface mine machinery world market
Mining industry no 4 110 pp 48–54
[10] Ivanov I Yu, Komissarov A P, Lagunova Yu A and Shestakov V S 2015 Intensification of the
rock excavation processes News of higher educational institutions. Mining journal no 3 pp
94–100
15th International Conference on Industrial Manufacturing and Metallurgy
IOP Conf. Series: Materials Science and Engineering 966 (2020) 012138
IOP Publishing
doi:10.1088/1757-899X/966/1/012138
6
[11] Kuvshinkin S Y and Ivanova P V 2019 Developing a methodology for estimation of excavation
techniques for given operating conditions IPDME 2019 IOP Conference Series: Earth and
Environmental Science pp 378 012121 doi: 10.1088/1755–1315/378/1/012121
[12] Dindarloo R, Siami-Irdemoosa E and Frimpong S 2016 Measuring the effectiveness of mining
shovels Mining Engineering vol 68 no 3 pp 45–50
[13] Nehring M, Sciprofile P F, Sciprofile M S and Kizil E Haÿ 2017 A comparison of strategic
mine planning approaches for in-pit crushing and conveying, and truck/shovel systems
International Journal of Mining Science and Technology vol 28 pp 205–14
doi:10.1016/j.ijmst.2017.12.026
[14] Kasyanov P A, Shestakov V S and Zakharov A A 2017 Calculation of the efforts in the hoisting
ropes of the excavator ʻstraight shovelʼ Technological equipment for mining and oil and gas
industry collection of works of XV International scientific and technical conference pp 283–6
[15] Komissarov A P, Lagunova Yu A, Shestakov V S and Lukashuk O A 2018 Estimation of the
mode parameters of the main mechanisms of an excavator Mining equipment and
electromechanics no 3 143 pp 3–8
[16] Pumpur E V, Knyazkina V I, Safronchuk K A and Ivanov S L 2019 Estimation of the factors
influence on a strategy choice of the excavator maintenance service Mountain information-
analytical bulletin no 12 special issue 41 pp 3–19 doi 10.25018/0236-1493-2019-12-41-3-19
[17] Knyazkina V I, Safronchuk K A and Ivanov S L 2019 About possibility of immediate
evaluation of technical condition of mining equipment using signal value of acoustic
emission friction IOP Conf. Series: Materials Science and Engineering 560
doi:10.1088/1757-899X/560/1/012068
[18] Safronchuk K A, Knyazkina V I and Ivanov S L 2019 Mobile lubrication and filling units to
reduce mining machines and equipment downtime when providing maintenance IOP Conf.
Series: Materials Science and Engineering 560 doi:10.1088/1757-899X/560/1/012088
