507 research outputs found
Mine Road Design and Management In Autonomous Hauling Operations: A Research Roadmap
In truck-based hauling systems, the mine haul road network is a critical and vital component of the production process. As such, under-performance of a haul road will impact immediately on mine productivity and costs. Operations safety, productivity and equipment longevity are all dependent on well-designed, constructed and maintained haul roads. With the advent of autonomous haul trucks, the haul road itself becomes all the more critical to the success of these type of operations; not only in relation to mine operators requirements for safer and more efficient and predictable haulage systems, but also in response to autonomous truck manufacturers' requirements for a more predictable and controlled operating environment.This paper presents a brief summary of the state-of-the-art in surface mine road design and then proceeds to examine the design and technological challenges associated providing a safe, predictable and affordable road for autonomous mine haul trucks. The paper serves as a basis for evaluating the contributions that enhancements in road design and management can deliver to autonomous mining operations, an initiative that also has scope for adoption within the operating life of many mines, haul roads and haul trucks
Investigation of direct drive hydraulics implemented in mining loader
The conventional mining loader is a diesel-hydraulic off-road mobile machine that is expected to routinely operate in enclosed areas. Such machines could benefit from more efficient hydraulic solutions. One avenue of improvement lies in electrification, which in itself is advantageous to underground mining machinery that would otherwise require expensive ventilation of their ICE exhaust. The high controllability of brushless DC motors allows direct pump control instead of conventional valve control, eliminating throttling losses. This work investigates the efficiency of such a direct-driven valveless hydraulic system for the front end of a mining loader and compares it to a conventional load-sensing system that was previously installed in the same machine. Economic viability of the described system is analyzed based on a real life working cycle, and the control software implemented as part of the work is described.
The efficiency of the direct-driven system was determined to be superior in all tested cases, increasing from 21% to 53% at high velocity and from 2% to 22% at low velocity and maintaining a very flat efficiency curve over most loads and velocities. The direct drive hydraulic system is capable of energy regeneration, recouping a portion of energy used for lifting thus allowing longer runtimes with a given battery capacity. These advantages were found to be enough to offset the higher up-front cost except for equipment with lower than usual lifespans.Kaivoslastarit ovat usein dieselhydraulisia työkoneita, jotka monesti toimivat maanalaisissa kaivoksissa. Sähkökäyttöiset toimilaitteet ovat yksi mahdollinen tapa parantaa näiden koneiden energiatehokkuutta, eteenkin suljetuissa tiloissa, joissa polttomoottorin pakokaasujen tuulettamisesta aiheutuu huomattavia kustannuksia. Sähkömoottoreiden hyvä hallittavuus mahdollistaa venttiilittömän pumppuohjatun hydraulijärjestelmän, joka ei kärsi venttiilihäviöistä. Tämä työ vertailee pumppuohjattuja suoravetohydraulisia kaivoslastarin toimilaitteita saman lastarin alkuperäisiin kuormantuntevalla säädöllä toteutettuihin, keskittyen hyötysuhteeseen sekä suorituskykyyn. Näin muokatun lastarin taloudellista kilpailukykyä tarkastellaan oikean kaivostyösyklin avulla. Työn osana on myös rakennettu kaivoslastarin toimilaitteinen sähköinen hallintajärkestelmä, jonka rakenne ja toiminta esitetään.
Pumppuohjatun hydraulisen järjestelmän hyötysuhteen havaittiin olevan nostotyössä parempi kaikissa tilanteissa hyötysuhteen noustessa nopeilla liikkeillä 21 prosentista 53:een, ja hitailla liikkeillä 2 prosentista 22:een. Pumppuohjattu hydrauliikka kykenee myös potentiaalienergian talteenottoon, mahdollistaen pidemmän käyntiajat samalla akkukapasiteetilla. Nämä edut ovat taloudellisesti riittäviä kompensoimaan laitteiston korkeamman hinnan lyhytikäistä kalustoa lukuunottamatta
Evaluation of two different mechanized earth moving technologies truck and shovel and IPCC for handling material from a large open pit mine using requesite design and operational conditions, efficiency, cost , skills and safety as criteria using sishen iron ore mine as a case study
An advanced coursework and a project submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements of MSc. Engineering
(Mining), November 2015General
For mining operations, both underground and open cast, there are generally
accepted criteria used to arrive at the optimum mining method with which to exploit
the ore body economically. Having selected the optimum mining method, mining
companies should then make the decision to also select the optimum technology to
apply given the various options that are now available.
In the case of a shallow massive ore body where open-pit mining has been selected
as the optimum mining method, the use of conventional trucks and shovels has been
the popular choice but over the years, as pit become deeper, and stripping ratios
increase, growing interest and adoption of in-pit crushing and conveying for both ore
and waste has been gaining ground with several mining sites currently now
operating, testing the systems or conducting studies at various stages for In-pit
Crushing and Conveying (IPCC) in its different configurations (Chadwick, 2010).
Open pit mining general involves the movement of pre-blasted or loose waste ahead
of underlying ore out of the pit or to a previously mined part of the pit. This is then
followed by the drilling and blasting or loosening of the ore and transportation to the
processing plant or stockpiles.
The conventional Truck and Shovel open pit operation involves the use of shovels –
electric rope shovels, diesel or electric hydraulic shovels or excavators or front-end
loaders to load the blasted, or loose waste and ore material in the pit onto mining
trucks which haul the material to crushers or stockpiles if it is ore or to waste dumps
in the case of waste.
In a Fully Mobile IPCC (FMIPCC) system, the broken or loose material in the pit is
loaded into a crusher or sizer by a shovel, continuous miner or dozer, crushed to a
manageable size and transported by conveyor belts to the waste dump where it is
deposited in place using spreaders if it is waste or onto stockpiles if it is ore.
A combination of the two systems is where trucks dump material loaded at the face
into a semi mobile crusher or sizer located in the pit close to the loading points
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before conveying to destination thereby reducing truck haulage distance. In the
semi-mobile configuration, the crusher is relocated closer to the loading points to
minimise the hauling distance. Other various configurations are also employed
depending on the various considerations. Although the Truck and Shovel system is
considered as the convention in open pit mining, the IPCC system is not a new
concept and has been operational on a number of mines worldwide for quite a
number of years (Szalanski, 2010). Loading and hauling receive great attention
especially in a high volume open pit mines due to the high cost contribution to the
overall operation and therefore, if optimised, good cost savings can be realised
(Lamb, 2010).
Figure 1: Sishen Mining Cost Breakdown
In the case of Sishen Loading and Hauling costs constituted 67% of the mining costs
including labour mining support services in 2013 (Kumba Iron Ore, 2013). This
picture remains unchanged to a large extent. In some cases the hauling cost alone
can make up as much as 60% of the mining operating cost (Meredith May, 2012)
Selection of a materials handling system between Truck and Shovel (T/S) and In-pit
Crushing and Conveying (IPCC) has proven to be difficult due to limited
understanding of the IPCC system especially its advantages and disadvantages
relative to the Truck and Shovel system. The aim of this research was to unpack
these two systems in terms of their applicability using studies conducted at Sishen
6,5%
8,8%
29,1%
22,7%
9,7%
0,6%
1,3%
0,4% 7,0%
4,2%
3,7% 5,9%
Sishen Mining Cost 2013
Blasting Drilling Hauling
L&H Contractors Loading Maintenance Other
Mining Manangement Mining Engineering Mining Other
Resource Management SHEQ Mining Support
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Mine as well as develop some scorecard that could be used to select one over the
other one.
Sishen Case Study
Sishen Mine is an iron ore open pit mine located in the Northern Cape province of
South Africa and is part of Kumba Iron Ore Company which is
Anglo American PLC. The mine has been in operation since 1953 with the current
life of mine going up to 2030. It produces 44Mt tonnes of product from a 56Mt
mine ore at a life of mine strip ratio of 4. One of the planned expansion
the north part of the mine known as the GR80 and GR50 areas. Mining in these
areas will require pre-stripping of
290Mt of clay material over the life of mine to expose the ore in pre
volume phases.
Figure2: Sishen Pit –Sishen Mine 2014.
Sishen mine is constantly evaluating various technologies in its mining operations
aimed at improving its bottom line by way of increasing productivity and efficiency,
reducing costs and improving safety, however, the last time that the mine considered
evaluating a technology that significantly could have resulted in a totally different
operational philosophy was i
contracted to institute a study to evaluate technology options for mining and moving
majority owned by
a minimum of 437Mt of calcrete and the underlying
pre-
g in 2007 when Snowden Mining Consultants
run-ofmine
areas is in
-planned time and
were
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55 Mt of the calcrete/clay material per year from the waste pushback area in the
GR80/GR50 area of the mine from 2009 till 2030. Snowden completed the
Prefeasibility study in early 2008 in which they evaluated a conventional Truck and
Shovel operation as well as IPCC. Economic viability of both systems in various
configurations was demonstrated with the use of larger trucks and shovels ranked as
the most economic option in terms of Net Present Cost (NPC), unit owning and
operating cost per mined tonne and, to a less extent, in terms of risk and other
considerations. In this case, the Truck and Shovel option was more economic than
both IPCC configurations. However the small difference in the cost figures gave rise
to interest in further evaluations.
Following the Snowden study, Sishen engaged Sandvik Mining and Construction in
2008, to review the work done by Snowden and provide more detail and practical
input to the IPCC system at scoping level. In the review, the IPCC system was
shown to be the economic approach for the waste removal from the target area in
terms of owning and operating cost. Practicality was also demonstrated and the case
for the consideration of the IPCC system was put forward to Sishen.
A further consultant, Sinclair Knight Merz (SKM) of Australia, was engaged, in the
later part of 2008, to further evaluate and optimise the IPCC option to further
demonstrate practically in detail at a feasible study level and strengthen its case by
mitigating perceived risk. This included equipment specifications, mine and
equipment layout per period per bench and risk assessment on the IPCC options.
The mine, however, implemented the conventional truck and shovel option using
larger equipment. The final decision was to stick with the current set up of Truck and
Shovel system and gradually replace the current fleet of 730E Komatsu (190 tonne
payload) trucks with the 930E or equivalent ( 320 tonne payload) and the current
XPB 2300 P& H electric rope shovels and CAT 994/Komatsu WA1200 front end
loaders with XPC 4100 P&H electric rope shovels, Komatsu PC8000/Liebherr 996
diesel hydraulic shovels and LeTournea L-2350 front end loaders to reduce the
number of equipment and manage the operational cost.
This decision was based on issues around initial capital investment, flexibility of the
system to suit changing mining plans, ability of current personnel to run the system
and general low risk appetite for change. The adopted option has its own challenges
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such as supporting infrastructure requirements, labour intensity and associated low
productivity and high cost, fleet management challenges to achieve required
productivity constantly, supplies such as fuel and tyres and safety issues due to
traffic density.
A high level recalculation of the costs using current information was done as part of
this research. For simplicity, no escalations or discounting were applied on future
expenditure. The estimated unit owning and operating costs in 2014 terms for the
study area were as follows:-
Fully Mobile IPCC (FMIPCC) option ZAR 10.38/t,
Semi Mobile IPCC (SMIPCC) option ZAR 13.12/t,
Truck and Shovel option ZAR 15.80/t.
The objective of this research is to use lessons from the Sishen case as well as
other operations and gather expert views with the aim of establishing criteria that
could be applied in a preliminary evaluation that would determine the suitability of
either of the materials handling options.
General Approach
The costs were recalculated using as much current information as possible. Other
considerations including advantages and disadvantages of either of the systems
were examined in more detail, with real life examples examined where possible. This
resulted in the establishment of generalized criteria for the selection of mining and
transport technology for a large open pit mine with focus on conventional Truck and
Shovel systems on one hand and IPCC systems, in their various formats, on the
other. These criteria which identify conditions necessary for the successful adoption
and implementation of either of the systems could then be used as input into the
decision to carry out any further detailed studies of the options. The previous study
reports on the Sishen mine case were examined, input parameters to the
calculations checked and the general approached analyzed for practicality. The
relative costs were also viewed for comparative purposes.
Literature on these two main systems was reviewed including that from conferences.
Other large operations running either one or both systems were looked at to gain
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further insight. Original Equipment suppliers’ views on these systems were also
looked at through many articles in the public domain. Sishen mine has previously
had the IPCC system running in the same part of the mine in a semi mobile
configuration, crushing and conveying waste. It was then changed to become a
supplementary system for the ore handling system and the in pit crusher has never
been relocated. The Truck and Shovel system took over the movement of all the
waste and most of the ore at the mine. Lessons from these experiences were
incorporated in this study
New applications for phosphoric acid fuel cells
New applications for phosphoric acid fuel cells were identified and evaluated. Candidates considered included all possibilities except grid connected electric utility applications, on site total energy systems, industrial cogeneration, opportunistic use of waste hydrogen, space and military applications, and applications smaller than 10 kW. Applications identified were screened, with the most promising subjected to technical and economic evaluation using a fuel cell and conventional power system data base developed in the study. The most promising applications appear to be the underground mine locomotive and the railroad locomotive. Also interesting are power for robotic submersibles and Arctic villages. The mine locomotive is particularly attractive since it is expected that the fuel cell could command a very high price and still be competitive with the conventionally used battery system. The railroad locomotive's attractiveness results from the (smaller) premium price which the fuel cell could command over the conventional diesel electric system based on its superior fuel efficiency, and on the large size of this market and the accompanying opportunities for manufacturing economy
Ecological and economic evaluation of quarry trolley trucks
Open-cut mining is the main way to extract minerals. Up to 80% of the rock mass produced by that is transported by dump trucks with diesel engines. Atmospheric gas pollution is an essential disadvantage of using diesel vehicles, especially in deep formations. Exhaust gases from diesel vehicles have a detrimental effect on human health and the environment. Constant exposure of exhaust gases on the body can cause immune deficiency, bronchitis, cerebral vessels and nervous system suffer. The higher the depth of mining the higher the concentration of machinery on formations and the worse the conditions of natural ventilation of the working space. At the depth of quarries over 200–250 m air pollution by harmful substances at the workplace leads to a gradual increase of the maximum permissible concentrations. That affects both people and economy of the enterprise since it entails the necessity to shut the career down, deteriorate visibility on the highway, which also causes a partial or total suspension of equipment operation. Transfer of dump trucks to electricity is a prospect way to solve the problem. Together, all the positive qualities of trolley trucks reduce the maintenance costs of transportation of rock mass by 15–20%, as well as exclude the gassing of the quarry and formation of smoke. Need for power from the contact network is the most serious drawback of trolley truck. Today, thanks to modern technologies, eliminating most of the drawbacks of trolley trucks is not difficult. Quarry trolley trucks are better used only for long-term development, since the content of the trolley line contact requires attendance and maintenance. The payback period can be 2–4 years
Ultra-heavy axle loads: Design and management strategies for mine pavements
The drive for greater cost efficiencies in surface mining has led to the development of ultra-heavy off highway trucks currently capable of hauling payloads of 345 tons. Typical axle loads in excess of 400 tons are applied to unpaved mine haul roads that have historically been designed empirically, relying heavily on local experience. In the absence of a formal haul road design methodology, good roads eventually result ? but the learning curve is steep & slow. This approach does not lend itself to an understanding of the road design process and more importantly, if the haul road performance is sub-standard, does not easily allow the underlying cause of the poor performance to be identified. With the trend in increasing truck size, haul road performance has become unpredictable, difficult to manage and costs of both maintaining the road and operating the truck have also increased prohibitively. Most surface mine operators agree good roads are desirable, but find it difficult to translate this requirement into an effective and responsive road design and maintenance management system.To meet this need, an integrated approach to pavement system geometric, structural, functional and maintenance design components was developed, taking into account road construction costs, vehicle operating costs and road maintenance costs. Since mine roads are built and operated by private companies, minimisation of total transportation costs is required. This paper presents an integrated mine haul road design and management strategy and illustrates the value of its application through several application case studies. A mechanistic approach to structural design resulted in a 29% saving in construction costs and also provided better service, whilst the optimal selection and management of wearing-course materials also provided better functionality at lower total transportation cost. Environmental considerations were addressed by the characterisation of wearing course material performance , both from a rolling resistance and fuel consumption perspective and a fugitive dust emission modelling and palliation perspective
Replacing combustion engines with hydrogen fuel cells to power mining haul trucks: challenges and opportunities
With the proven advantage of higher energy density in hydrogen fuel cells over batteries, there is potential to apply fuel cells to power mining haul trucks. This study aims to evaluate the technical and economic feasibility of hydrogen fuel cell electric mine trucks as an alternative to current mine haul trucks. Specifically, the project: (1) developed an economic framework for evaluating the integration of renewable energy powered haul trucks into mining; and (2) applied vehicle drivetrain and energy simulation in Matlab/Simulink to elucidate the challenges and opportunities of incorporating hydrogen fuel cell technology into the current form factors of mine haul trucks. First, the study uses an optimization model to characterize the impact of production, market and policy parameters on a mining firm’s decision of what types of trucks (with or without renewable technology) to deploy to minimize its overall costs, including costs associated with greenhouse gas emissions. Second, is an investigation of the significant technical challenges and opportunities associated with integrating hydrogen fuel cells in mining haul trucks using the vehicle drivetrain model and simulation experiments. The results show that even with green energy government incentives and levies for greenhouse gas emission, the cost of operating green energy trucks needs to be competitive to ensure they minimize a mining firm’s cost. However, to utilize a hydrogen fuel cell truck in the mine, a new vehicle frame is likely required to support the integration of the technology. This would require financial and technical investments by original equipment manufacturers and mining firms to make the transition --Abstract, page iii
The application of probabilistic logic to identify, quantify and mitigate the uncertainty inherent to a large surface mining budget
Mining is a hugely expensive process and unlike manufacturing is based on an ever
diminishing resource. It requires a continuous infusion of capital to sustain
production. A myriad of factors, from the volatility of the markets to the surety that
the minerals are really there, “plagues” both management and investors. The budget
tries to predict or forecast future profits and acts as a roadmap to all stakeholders.
Unfortunately, most of the time the budget of a mine degenerates to the extent of a
collapse, sometimes very soon into the new budget period. This problem plagues
both small and large mines indiscriminately. The budget is dictated in absolutes, and
little or no variability is allowed.
This thesis aims at developing a process to predict the probability of failure or
success through the application of probabilistic logic to the simulation of the budget.
To achieve this, a very detailed modelling tool is required. The model must replicate the actual mining process both in time and actual spatial representation.
Enabling technology was developed over a period of five years, primarily based on
the Runge Software Suite. The use of activity based costing enabled the budget to
be simulated and expressed as a probability distribution. A Pareto analysis was done
on the main cost drivers to extract the most important elements – or key drivers - that
need to be manipulated. These distributions were mapped against real data and
approximated with the use of the three parameter Weibull distribution.
Simulation using Xeras® (Runge) proved to be impossible. This is due to the time
needed for setup and processing. The budget was described as an empirical
function of the production tonnages split according to the Pareto analyses. These
functions were then utilised in Arena® to build a stochastic simulation model. The
individual distributions are being modelled to supply the stochastic drivers for the
budget distribution. Income, based on the sales, was added to the model in order for
the Nett profit to be reflected as a distribution. This is analysed to determine the
probability of meeting the budget.
The underlying analysis of an open pit mining process clearly reflects that there are
primary variables that may be controlled to trigger major changes in the production
process. The most important parameter is the hauling cycle, because the haul trucks
are the nexus of the production operation. It is further shown that the budget is primarily influenced by either FTE’s (full time employees, i.e. bodies) or funds
(Capex or Opex) or a combination of both.
The model uses probabilistic logic and ultimately culminates in the decision of how
much money is needed and where it should be applied. This ensures that the
probability of achieving the budget is increased in a rational and demonstrable way.
The logical question that arises is: “Can something be done to utilise this knowledge
and change behaviour of the operators?” This led to (IOPA – Intelligent Operator
Performance Analyses) – where the performance or lack thereof is measured on a
shift by shift basis. This is evaluated and communicated through automated
feedback to the supervisors and operators and is being implemented. Early results
and feedback are hugely positive.
The last step is prove where capital (or any additional money spend) that is applied
to the budget will give the most benefit or have the biggest positive influence on the
achievement thereof.
The strength of the model application lies therein that it combines stochastic
simulation, probability theory, financial budgeting and practical mine schedule to
predict (or describe) the event of budget achievement as a probability distribution.
The main contribution is a new level of understanding financial risk and or
constraints in the budget of a large (open pit) mine.Dissertation (MSc)--University of Pretoria, 2014.Mining EngineeringMEngUnrestricte
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