评估和优化采矿设备的效率外文文献

Evaluating and optimizing the effectiveness of mining equipment the case of Chibuluma South underground mine Brighton Samatemba a Long Zhanga Bunda Besab aSchool of Economics and Management China University of Geosciences Beijing Haidian District Beijing 100083 China bSchool of Mines University of Zambia Marshlands Lusaka 32379 Zambia a r t i c l e i n f o Article history Received 10 November 2019 Accepted 11 December 2019 Available online 15 December 2019 Handling Editor Zheming Tong Keywords Optimization Mining and technology Equipment management Equipment productivity using R OEE a b s t r a c t The effectiveness of mining equipment is a huge challenge in mining which affects mining companies competitive advantage in the global mining sector It is therefore very important for the mining industry to utilize its intensive equipment with proper measurements In this paper an algorithm has been developed using Rstudio software to determine and evaluate the sensitive inputs to the life cycle of mining equipment as well as determine and analyze the Overall Equipment Effectiveness as a measure to use in evaluating and optimizing the effectiveness of mining equipment The algorithm was validated in the fact that the trends of the sensitive inputs to the equipment life cycle were determined The most sensitive inputs to the equipment life cycle such as process cycle times utilization maintainability performance and production effi ciencies of drill rigs loaders and dump trucks were all evaluated and the overall equipment effectiveness was found to be below 50 percent for all the three types of equipment The model developed in this paper is an algorithm with code that s reproducible and reusable with a few changes of variables for an underground mine The algorithm uses equipment operational records for effective planning and optimizing of mine production operations 2019 Elsevier Ltd All rights reserved 1 Introduction Equipment selection and optimization is one of the most chal lenging problems in the mining industry today especially matching the correct number of equipment required to the amount of ore to be hauled In mining ore production involves drilling loading and hauling Chibuluma South underground mine was chosen as the case study due toits modernization and use of trackless equipment The utilization of its equipment was used to fi gure out a way to optimize the equipment and reduce the overall cost of materials handling The problem of equipmentoptimization is oftencascaded by the intermediate parameters Using a piece of equipment effectively depends on its utilization availability and the age of the equipment The main objectives of a mining operation are to pro duce resources at the minimum possible cost and equipment se lection and productivity play a major role at ensuring this is possible because materials handling is averycostlyoperation in the mining industry The future of most industries today is in the industry s effective use of technology and the mining industry is not an exception to this phenomenon This paper focuses on using Rstudio software to develop a productive and effective algorithm that will be used as an important tool for equipment optimization and effectiveness at Chibuluma mine as well as other mining companies and reduce the overall cost of materials handling The cost of haulage operations in mines is on the rise due to the longer haul routes and higher fuel consumption necessitated by deep ening mines Park et al 2016 and Chibuluma mine is currently more than 600 m below the surface with a haul route of more than 3 km Various techniques have been developed to date by many researchers Ercelebi and Bascetin 2009 to optimize the haulage systemwhich form a considerable partof mining costs The analysis of the rate of operation in terms of loading equipment ore yield and rate of return based on the transporting equipment and the proposal of a modeltooptimize the numberand combination of the equipment deployed Salama and Greberg 2012 did a simulation on a loading haulage system to optimize the number of trucks used in an underground mine and proposed a system operation plan to improve the effi ciency of the haulage system According to studies that have so far been conducted we can easily tell that a productive and optimal haulage equipment forms a very important part of the Corresponding author E mailaddresses Brighton samatemba4 B Samatemba zhanglongdragon L Zhang bbesa unza zm B Besa Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage https doi org 10 1016 j jclepro 2019 119697 0959 6526 2019 Elsevier Ltd All rights reserved Journal of Cleaner Production 252 2020 119697 mining operation and since modern equipment is capital intensive and increasingly sophisticated it is important that it stays in rev enue generating jobs and be highly effi cient and effective in its available time There are several available means of ensuring that the equipment is achieving the factors that lead to better asset management which include but are not limited to increase in uti lization rate higher reliability and effective maintainability Since it is well known that these factors differ considerably in terms of the sustained cost to equipment effectiveness ratio it is therefore very important to know the exact areas where efforts need to be focused in order to improve the equipment effectiveness as whatever gets measured gets done Campbell et al 2015 1 1 Background of equipment optimization at Chibuluma South Mine The selected site was Chibuluma South Mine which is located at latitude 12 53 S and longitude 28 05 E approximately 15 km west of Kitwe on the Copperbelt province of Zambia Chibuluma mine is owned by Jinchuan Group Company Limited with 85 shares and Zambia Consolidated Copper Mines ZCCM with 15 shares and it is operated by Metorex group of companies Mine Reports 2016 The town of Kalulushi was developed in the 1950s by Roan Selec tionTrust RST to support the Chibuluma East and West mines The mine has its main operating asset the Chibuluma south and under development is the Chifupu ore body which is approximately 1 7 km south westof Chibulumasouth mine Chibuluma south mine is an underground mine capable of treating up to 50 000 tonnes of Run off Mine ore per month and is located in Kalulushi town of Zambia The main products of the mine are copper and cobalt which are usually exported as processed ore after metallurgical treatment Chibuluma Mine was selected due to its modernization and use of trackless equipment 1 2 Importance and signifi cance of research The mine is a modern mine which is designed to use trackless equipmenttherefore measuringthefactors infl uencingthe equipment effectiveness and thorough analysis of well defi ned performance indicators will allow the mine to assess the progress of improvement initiatives and prioritize resources In the mining industry equipment optimization or effectiveness is mostly asso ciated with both its utilization and availability but the impacts of the aforementioned factors are not that substantial compared to other factors which are usually ignored in the mining industry as well as at Chibuluma Mine in this case The objective of this paper is to develop a stochastic equipment life cycle model to determine the productivity of equipment for mining companies with two main areas of focus 1 Determination of the most sensitive inputs tothe life cycle of the equipment 2 Equipment life cycle model to estimate the optimization of the equipment based on availability utilization and production effi ciency 1 3 Stages of equipment life In order to develop a reliable and effective equipment life cycle model the stages of equipment life have to be defi ned Equipment life can be defi ned using three different variables namely physical life economic life and profi t life Mitchell 1998 Both the physical and economic life must be calculated when considering equipment life because they provide an effective equipment replacement analysis on which major equipment replacement decisions are made Douglas 1975 and the profi t life can then be calculated from the information taking note of the depreciation downtime in vestment maintenance and repairs of which these factors are also integral to replacement analysis Gransberg et al 2006 All three stages of equipment life can be compared in accordance with Fig 1 which helps illuminate the relationship amongst the three stages where it can be clearly seen that it takes some time for a newly acquired equipment to cover the capital cost of its procurement cost When it covers its procurement cost it then goes into a phase where it earns its maximum profi t just before fi nishing into a phase where it s productive time costs more than it earns due to repairs and maintenance during operational hours Therefore mines need to have tools which will help them determine a point in time when theequipmentneeds replacingeither bypurchaseorlease based on the usage plan of a particular equipment 1 3 1 Physical life The physical life in this research paper will be taken as the service life of the equipment This phase of the equipment life is largely impacted by repair and maintenance Gransberg et al 2006 and comes to an end when the equipment is no longer operational Preventive maintenance is avery important partof this physical life because it determines how long a piece of equipment will last From experience a well serviced equipment usually has a longer lifespan compared to one which is not serviced at all 1 3 2 Profi t life The profi t life is the time when an equipment earns more than the maintenance and repair costs as well as more than its cost to own and operate According to Douglas 1978 this is the most desirable time of owning and operating the equipment When major components of the equipment wear out then the equipment moves into a phase where it is no longerprofi table and a decision to replace it is made by its owner It is therefore important for mining companies to be able to estimate this time period so as to maximize on production and equipment effi ciency 1 3 3 Economic life The economic life is the period when the ownership costs are equivalent to the operating costs Economic life is based on decreasingownershipcostsandincreasingoperatingcosts Mitchell 1998 meaning that when the operating costs become more than the ownership costs then a piece of equipment is costing more to operate than own Therefore to maximize on profi ts a piece of equipment should be planned to be replaced before it reaches the economic life 1 3 4 Life cycle cost analysis The equipment life cycle cost analysis consists of equipment replacement analysis and models life cycle costs and equipment decision procedures Life cycle costs for equipment consist of Fig 1 Equipment life Douglas 1978 B Samatemba et al Journal of Cleaner Production 252 2020 1196972 ownership and operating costs Operating costs include but not limited to operator costs repair and maintenance tire and tire repair costs and fuel Gransberg et al 2006 while ownership costs include but also not limited to investment costs storage costs taxes depreciation costs insurance and initial costs Peurifoy and Schexnayder 2002 This research utilised a stochastic model because stochastic functions improve the accuracy of life cycle costs 2 Methodology The profi t life in equipment calendar hours will be one of the tools that will be used in this paper to determine the effectiveness and optimization of equipment in ensuring that maximum profi t is gained from the deploying of a piece of equipment The Chibuluma South Mine equipment data is the one mainly utilised in this research to conduct the analysis to determine the optimal profi t life of the equipment The equipment life cycle models have been proposed according to Peurifoy and Schexnayder 2002 2 1 Overall equipment effectiveness One of the tools that can be used to evaluate the effectiveness of mining equipment is a tool called the Overall Equipment Effec tiveness OEE Index which was developed by the Japan Institute of Plant Maintenance JIPM This wasproposedbySeiichi Nakajima to measure the effectiveness of equipment in the manufacturing in dustry Nakajima 1988 For manufacturing industries OEE is defi ned generally as follows OEE availability performance rate quality rate 1 Where Availability A Actual running time total hours 100 2 Performance rate Pr total output potential rated output 100 3 Quality rate Q good output total output 100 4 However for these equations to be applied in the mining in dustry some slight modifi cations need to be made for them to suit The most diffi cult to defi ne in the mining industry is the quality rate which seems more relevant and applicable to drill rigs in terms of hole deviations as well as jams However this is less relevant to dump trucks and loaders although for this study it was measured as the number of loads of ore that was moved success fully without much delays associated with stoppages or equipment failure hence referred to as production effi ciency rather than quality rate The performance rate in the mining industry is similar to the utilization rate and is necessarily referred to as such hereby leading to the following equations OEE availability utilisation rate production efficiency 5 Where Availability A actual running time total hours 100 6 Where Pe Production effi ciency rated capacity Total hours Sheduled Maintenance hours Totals hours There is need to have a clear understanding of the factors above and their impact on the equipment effectiveness in order to help know which areas require optimization efforts and focus at Chi buluma south mine and the mining industry at large 2 1 1 Availability of equipment Equipment availability is one of the most widely used factors in the evaluation of equipment effectiveness in the mining industry including Chibuluma South Mine It is widely used because of its simplicity in terms of its applicability as well as understanding Availability is defi ned as the ratio of the time during which an equipment is capable of performing its functions actual running time to the total number of hours in a given period total hours However there is no industry agreement on the defi nition of the input parameters such as the numberof hours differentmines have different operating shifts Chibuluma South Mine operates three 8 h shifts resulting in a 24 h operating period per day for 7 days aweek The scheduled equipment operating hours are used as inputs Availability depends on reliability and maintainability Dhillon 2008 which are both functions of several other factors such as Mean Time Before Failure MTBF equipment waiting times etc 2 1 2 Utilization of equipment Equipment utilization refers to the time an equipment is used to perform its functions during its available time During the time the equipment is in the running state it s rarely entirely used to perform the functions it was designed to do throughout the time Sometimes the equipment is designated as a back up unit it may also be idle due to the lack of an operator or due to the process cycles The values of equipment utilization largely depend on input data which most of the times comes from the onboard instruments of the equipment Unfortunately this is notthe case for some values at Chibuluma South Mine asthe underground equipment lackthese instruments therefore the load weight and time measures are done using an external equipment installed at the open pit or portal entrance and exit point However the values obtained in this manner are usually subject to a bias of their own They are mostly Utilisation rate U total hours standby idle hours downtime total hours downtime 100 7 Production Pe actual production time actual running time standby idle hours rated capacity 100 8 B Samatemba et al Journal of Cleaner Production 252 2020 1196973 rough estimates which require an accurate availability follow up which is also currently defi cient at the mine resulting in a utili zation record which is biased Equipment utilization only gives a partial picture of the equipment effectiveness due to the lack of assurance of reasonable input data Downtime is one of the factors that plays an important role in equipment utilization Dhillon 2008 However downtime itself is even a more complex concept to clearly understand because it is interpreted in several different ways and depends on a lot of factors It is usually related to equipment reliability whose measure is connected to the Mean Time Between Failures MTBF The Mean Time Between Failures or Mean Time Between Shutdowns MTBS includes all interruptions due to equipment failure or maintenance procedures regardless of their nature Although the MTBF has some constraints of its own such as when the operation does not refl ect the adequate quantity of useful work undertaken by the equipment Then the expressed MTBF in the unit of time is inadequate but it is worth noting that it is one of the adequate measures of equipment effectiveness although it is not used by a lot of mines it is in fact recorded at Chibuluma South Mine Downtime is not limited to active main tenance during which some preventive maintenance is carried out on the equipment but there is more such as waiting periods and unexpected equipment breakdowns etc Therefore reliable infor mation comprising all the components of downtime duration is a key factor in identifying and eliminating the processes responsible forthemosttimelosseswhichleadtopoorequipment effectiveness 2 1 3 Production effi ciency Production effi ciency is a very important measure of a com pany s performance in that it requiresthe minimization of costs and the maximization of profi ts for a given level of output Dhillon 2008 In the manufacturing industry effi ciency makes the best of a company s resources An effi cient company will produce a greater number of quality products with les