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By E Holloway

The optimisation of an open pit mine can be broadly split into two stages, the first being the ultimate pit optimisation (and subsequent stage designs), and the second being schedule optimisation. Macroeconomic uncertainty clearly impacts on both however interrelationships do also exist. Generally, the opportunity exists for the ultimate pit to be revised during each planning cycle, however when this reprieve is removed the uncertainty for the underlying business increases. As one example, the introduction of an in-pit waste dump can be seen to significantly limit the option to revise the ultimate pit. When in this situation there are two potential risks that present: (i) the long-term price used for the ultimate pit selection is optimistic, and too large of a pit is selected resulting in waste being mined which uncovers material not of a significant value to deliver a profit; (ii) the long-term price used for the ultimate pit selection is pessimistic, too small of an ultimate pit is selected, and ore of realisable economic value left behind. Both of these outcomes are risks and as such can be assessed and quantified. CITATION: Holloway, E, 2018. Incorporating economic variability into a strategic planning framework, in Proceedings Complex Orebodies Conference 2018, pp 88–90 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By David McMullen

Radiation plays a critical role in the thermal behaviour of hydrometallurgical process equipment. This effect is particularly important when designing refractory lined equipment used in pressure leach/oxidation processes. In order to simplify this non-linear mode of heat transfer, the effects of radiation had previously been incorporated in an equivalent convective film coefficient in finite element methods (FEM). This prior method omits the effects of radiosity, a critical aspect of radiation heat transfer, which affects the design of refractory lining systems in autoclave vessels. Given that 60% of the heat loss in actual plant practice of an autoclave is due to radiation, reliability in the FEM is therefore impacted. This study validates the use of radiosity in FEM through thermal loading using a combination of simple geometries to be applied to complex environments such as vessel nozzle clusters. The added benefits of using a radiosity load includes an increase in confidence in thermal distribution results, greater accuracy in determining appropriate refractory lining systems, weld overlay sizing, and increased accuracy in structural analysis.

Jan 1, 2014

By Murad Y. Abu-Farsakh, Md Habibur Rahman

The properties of all natural soil deposits are highly variable, and they are rarely homogeneous. Cone penetration tests (CPT) were used to assess the site variability, which was then incorporated into the Load and Resistance Factor Design (LRFD) of pile foundations. Data from six project sites with multiple CPT tests conducted at various locations were collected for this research. The semi-variogram was used to assess the spatial variability of CPT data (corrected tip resistance, qt) for each location. For each location, the coefficient of variation due to spatial variability (COVR,spatial) was calculated. From COVR,spatial and COVR,method, the total coefficient of variation (COVR,total) for each site was calculated, which was then used to calibrate the resistance factors (ϕspatial, ϕtotal) for use in LRFD pile foundation design. The findings of this study demonstrated the importance of using site variability in LRFD pile design. For sites with lower site variability than the design method (i.e., COVR, spatial < COVR, method), the value of the COVR, total will be decreased, and hence the resistance factors (ϕspatial or ϕtotal) will be increased (credit), and vice versa.

Sep 8, 2021

By A Murphy

Mining plants and infrastructure, and the decisions made by their designers, can have large impacts on their environmental and social context, commonly referred to as the site or plant footprint. They can also be the source of constructive contributions to sustainable development when designers are enabled via the information, systems and tools to incorporate sustainability in engineering processes. A facility’s footprint and the project’s contribution to sustainability – economic, environmental and social aspects – are now key considerations in regulatory approval processes and are the fundamental drivers of support, or opposition, from the project’s stakeholders.Historically, plant and infrastructure designers have not been well integrated with the environmental and social professionals who are engaged to pursue regulatory approvals. Despite this, many objectives central to technical and process engineering have in fact contributed positively to a facility’s footprint and indeed its contribution to sustainable development. Examples of these objectives include increasing process and energy efficiency, and minimising the quantities of waste requiring disposal. With the framework of sustainability, mining plant and infrastructure designers are indeed at the forefront of incorporating sustainability into resource industry projects and are central to the process of obtaining regulatory approvals and ongoing stakeholder support. The process of incorporation starts with a shared understanding of sustainability and sustainable development, and continues with project processes that facilitate information and knowledge exchange throughout the project life cycle.CITATION:Murphy, A, 2014. Incorporating sustainability into mining plant and infrastructure design, in Proceedings Life-of-Mine 2014 , pp 637–646 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By C Tomlin, C Gimber

Historically, key closure risks have been studied during operations and then further assessed as cessation of mining approaches. Only in the past couple of decades or so has progressive rehabilitation and closure become an integral part of regulatory frameworks, sustainable mine planning and more recently, new project and development planning. It is now broadly accepted that the best closure outcomes occur when rehabilitation and closure are properly considered upfront, during the early stages of a mine development project and well before mining occurs. Increasingly, regulatory processes are requiring more diligence on early closure planning, often as part of the environmental impact assessment (EIA) and approvals process, rather than later in dedicated closure study phases. There is an opportunity to use the information generated during this phase to make better decisions on project selection, design, mining methodology and all other facets of the mining operation.

Aug 2, 2023

By M. Fig, A. Juganda, M. Zurhorst, J. Brune, C. Strebinger, G. Bogin

"Understanding the airflow patterns in and around the longwall panel can help to identify poorly ventilated areas that may be prone to methane accumulation. Ventilation network modeling provides quick simulation time, and flexibility in adjusting airway parameters and ventilation controls. Such modeling is effective for analyzing linear ventilation networks in underground mines, but cannot compute flows in caved areas of hard rock mines or longwall gobs. The use of Computational Fluid Dynamics (CFD) enables a more detailed investigation of the interaction between the airflows in these caved areas but requires much longer computational times, designing complex meshes and determination of a variety of modeling parameters. Airway friction factors and ventilation controls are simple to implement in a network model but can be difficult to model and adjust in CFD. This paper will focus on using mine ventilation network simulation to identify and analyze key parameters that are affecting airflow distribution in and around the longwall panels, prior to more detailed analysis with CFD modeling, using the example of a longwall coal mine. INTRODUCTION In longwall coal mine ventilation systems common in the U.S., the main purpose of bleeder ventilation is to dilute methane gas and prevent the formation of explosive gas mixtures in the caved, poorly ventilated gob areas and adjacent mine workings. In longwall operation, these critical areas include the development headings inby the longwall face, and the gob. Methane-air explosions in these areas may be ignited by spontaneous combustion, rock-on-rock friction and other sources. Although rare, ignitions due to rock-on-rock friction caused by roof falls caving into the longwall gob are possible and were suspected in the Willow Creek mine explosions in 1998 and 2000 (Elkins et al., 2001; McKinney et al., 2001). Rock-on-rock frictional ignitions are difficult to prevent, as they occur in inaccessible areas. Therefore, rendering the gob area inert is essential to prevent the formation of explosive mixtures. Research by Gilmore et al. (2015) and Brune et al. (2015) has shown that gob inertization can be a difficult or impossible when using bleeder systems, since the flow of gases through the gob depends on the gob permeability and the amount of fresh air leaking from the face and the immediate roof caving conditions cannot be controlled by the mine operator. Having the ability to predict the location where explosive gas zones (EGZs) form inside the gob will be helpful for designing the best ventilation setup to minimize explosion and fire risks."

Jan 1, 2018

By S. Soren, K. Deo Mehta, G. Jha

The paper aims to find a sustainable sintering process through cleaner means, in order to achieve the desired outputs with zero environmental impact. At present, sintering has no control over its environmental impacts. These impacts occur when fossil fuels such as coal and coke are used in metallurgical sintering. These fossil fuels are undoubtedly effective in their assigned reducing task, but simultaneously emit about 220 kg of GHGs (greenhouse gases) per tonne of sinter produced. The current attempt has focused on reducing these emission levels by switching from coke to a renewable fuel source such as biomass. Biomass is a cleaner fuel source with a significantly lower emission footprint compared to coke. In the experimental campaign, sawdust and wood-charcoal were used in substitution for coke. Experiments were designed in a progressing substitution to obtain the maximum substitution ability without compromising the sinter properties. Sawdust as raw biomass source optimally substituted 10% of coke. The substitution levels were remarkably higher (30%) for wood charcoal due to its low moisture and high calorific values. A fuel blend with 30% biomass and remaining coke succeeded in producing a sinter with acceptable quality indices. Sinters prepared with or without biomass contribution shared an identical phase transformation and microstructures. In order to to maintain consistency in the process, every effort was made to maintain all operational and process parameters identically, except for the fuelling framework. Keywords: Sintering, sustainable, biomass, GHGs, fuel substitution

Jan 1, 2020

By Ruhi Bux, Akshay Verma, Mohini Saxena, P. Asokan

"Due to the colossal increment in the industrialization, the generation of wastes gathered as a result of different extraction, benefaction and generation processes is having an alarming problem for waste disposal. The best and most acceptable way is to use the waste in accordance to its potential for the generation of high value lucrative composite goods. The study in this paper elucidates the potential of several industrial wastes like fly ash, red mud and marble slurry dust for the production of different wood substitute products like doors, windows, roofing sheets and instant houses for the rehabilitation on the sites of catastrophes. Wastes were initially characterized for the physical, chemical and mineralogical properties and then used in different formulations with binder like Polymer along with natural fiber like Jute to intensify the physical as well as mechanical properties of the resultant composite. The study also reveals that these composites have better mechanical properties than the available ones like teak, medium density board, Rice husk board etc. Also, the fly ash and red mud composites have better mechanical properties than marble slurry based composites. The results fosters the implementation of natural fiber with the industrial waste in the generation of eco-friendly and non-hazardous composites.IntroductionOver the last few decades, there has been a tremendous increase in the generation of industrial wastes gathered as a result of various extractions, benefaction and generation processes. The condition worsens even, when it comes to high quantum generated wastes like Fly ash, Red mud and Marble slurry dust. The primordial motif behind the incorporation of industrial wastes as filler in the development of composites is primarily composed of two main objectives; Firstly waste management, the colossal waste dissemination in the environment has disturbed the ecological balance by polluting land, surface water, ground water, air, natural resources and even disturbing the public health [1]. Secondly, to act as a perfect substitute for the conventionally existing building materials, this will aid in dwelling places to many with the least incorporation of exhaustive natural resources as woods quid pro quo."

Jan 1, 2008

By J. Gholamnejad

In open pit mine planning and design, push back mine sequencing is widely used for long-term production planning. In push back design, a series of nested pits is generated and then considered as possible push backs with regard to the minimum push back width requirements. These nested pits are produced by parameterizing on one economic parameter like commodity price, mining or processing cost, stripping ratio, etc. The most important characterization of these push backs is that the innermost push back has the highest value per ton, the second innermost push back has the second highest value per ton, and so on. These nested pits are generated based on the best estimates of grade within a representation of the orebody in a three-dimensional matrix form. Therefore, the inherent uncertainty associated with reserve estimation (for our discussion, grade uncertainty) is not taken into account when push backs are designed. These methods do not attempt to establish which part of the deposit is likely to be worth most. This paper introduces a new algorithm that incorporates ore grade uncertainty during the pushback design process. The suggested strategy tries to seek to schedule risky blocks later in the extraction sequence. Keywords: open pit mine, push back, ore grade uncertainty.

Jan 1, 2007

By A N. Parry

In May 2018 Kasbah Resources Limited (“Kasbah”) completed an ore sorting test work program which was a precursor to releasing in July 2018 an updated Definitive Feasibility Study (“DFS”) for the Achmmach Tin Project in Morocco, which it is proposing to develop along with its joint venture partners. The testwork program evaluated ore sorting as a pre-concentration option to achieve early elimination of gangue and the low-grade component of ROM feed, thereby potentially:  Significantly upgrading the head grade of tin to the downstream processing plant.  Significantly reducing the required throughput capacity (and projected capital expenditure) of the downstream processing plant.  Reducing total consumables, power and water requirements in downstream processing.  Increasing the recovery of tin in the gravity and flotation circuit due to the higher feed grade achievable with ore sorting.  Reducing tailings tonnage, tailings cost and environmental footprint.  Using sorter rejects for mine backfill or road base applications. Key aspects of the design of the metallurgical testwork program centred around the need to ensure that samples representative of ROM ore feed (including projected mining dilution) were selected for the ore sorting testwork. The design and implementation of the ore sorting bulk testwork program is described, as well as a summary of the test work results and a discussion of the enhancement of the project economics reported by Kasbah, which led the company to adopt ore sorting as part of the proposed processing circuit in the updated 2018 DFS.

Nov 10, 2020

By C. B. Piazzarollo

Ceramic materials exhibit dispersion results after being subjected to various levels of stress, from the point of view of mechanical strength. With the focus on sustainable development and to improve the strength of these material, was incorporated ornamental rock waste into clay in up to 10% in mass to conform some samples, that was fired to 750ºC, 850ºC and 950ºC and submitted to technological tests. This paper presents an analysis of the technological properties of the samples through the use of Weibull statistic to determine which the best firing temperature for these red ceramic materials. The Weibull Modulus indicates a greater homogeneity for samples with 10R at 950ºC.

Jan 1, 2015

By T. A. Toney

With new lightweight designs, spirals have become standard equipment in coal preparation plants worldwide. To their credit, spirals typically show very low coal losses to the refuse stream under most operating conditions. However, spirals do tend to separate at cut points in excess of 1.80 S.G. Attempts to obtain lower cut points have typically resulted in coal losses to middlings. Middlings retreatment with secondary spirals is therefore becoming common place. Other forms of retreatment with water-only cyclones, hydrosizers, and recirculation have been attempted with some success. This paper reports on a novel (Patent Applied For) approach to retreating spiral middlings m a heavy-media-cyclone circuit.

Jan 1, 1998

By W. Boas, R. Silva, D. Yumi, L. Steffen

The continuity of the flow and stages within the mining process is essential to achieve success in its operation and results, especially when it comes to a gold mine. During the first seven months of 2022, crushing at the Morro do Ouro Mine had 19 stops in the primary crusher due to equipment blockage/obstruction, this could be due to the size of the material that was blasted with explosives and fed. The feeding of coarse material to the crushing plant impacts the operation in several ways, for example, premature wear of the equipment, reduction in the supply of the remainder of the beneficiation, reduction of the buffer pile and damage to the conveyed belt. In a mine located far from the community, the fragmentation improvement is mainly related to load increments or some other relatively simple change. However, when it comes to a mine located close to communities, alterations of this type must be analyzed in detail, as it can have an impact mainly in relation to vibration and flyrock. Aiming to improve the efficiency of the blasting, mainly in relation to the result of fragmentation, a project was created to improve the efficiency of the blasting with a focus on reducing the crushing stoppage and reducing the amount of material discarded due to inadequate granulometry. During the evolution of the project, several improvement solutions were proposed, for example adjustment of the power factor in relation to the geological characteristics of the rock mass, drainage, blasting geometry, vibration reduction techniques and several operational improvements. By using the techniques and methods identified as improvements during the project, it was possible to observe and quantify improvements in relation to the fragmentation of the blast. During the months of January to July 2022 there were 19 events. It was estimated that at this rate there would be 14 more blockage events, but there were only 3 events and that meant a 79% reduction in blockage. In addition to the reduction in crushing shutdown events, there was also a 53% reduction in the amount of ore that is discarded due to inadequate granulometry and, with that, the feed rate of the grinding system was able to reach the maximum feed limit due to the material being fed to the mill well fragmented, contributing to increase the production and productivity of the beneficiation process at the Morro do Ouro Mine in Paracatu-Minas Gerais-Brazil.

Jan 1, 2024

By John T. Ryan

FOR the first ten months of 1942, on which data are available at the time this is written, the coal-mining industry achieved a most creditable safety record, and ha1 figures for the year may show a record surpassing that of 1941 in which the industry reached the best accident rate in its history. The ten- month accident rate for both bituminous and anthracite mining in 1942 was 2.197 fatalities per million tons of coal mined, compared with a revised rate of 2.271 for the same months of 1941. The bituminous rate decreased from 2.139 in 1941 to 2.039 for ten months of this year, and the anthracite rate shows a reduction from 3.707 to 3.699 for the same period.

Jan 1, 1943

By R Stimpson, B Johnson, B Hesse

During a period of twelve months between FY18-19, a series of trials were conducted to compare production drilling accuracy using two different methodologies, and the subsequent impact this had on stope performance (dilution and recovery). Testing was conducted at a series of underground mines in Australia. The drill rig’s existing alignment processes were compared to a new technology system, with the following observations: • The new technology was proven to limit rig alignment error, thereby reducing average blasthole deviation, resulting in an increase in the number of holes drilled within tolerance by up to 160%. • The increased accuracy reduced stope dilution significantly by reducing over-break of subgrade ore, whilst also increasing drilled meters (faster stope-cycle time), reducing the bridged tonnes ratio, and facilitating the capture of previously uneconomical stopes. A cost-benefit analysis extrapolated from each of the trials showed the extent to which the new technology, when applied to production data, reduced average dilution, increased ore recovery as well as general drill and blast productivity. In one such trial, the new technology was proven to have reduced average dilution by net 45.4%, which if applied to a full year’s production data, would result in AUD8.2M additional ore recovered, with AUD4.5M less spent on wasted cost of haulage and processing of diluted ore. As a result, return per tonne would increase 22%, from AUD87 to AUD106. This improvement was maintained over the following 12 months – reducing average dilution from 22% in FY17 to 12.1% in FY19.

Mar 15, 2021

By P J. A Lever

This paper presents details of CRC MiningÆs work with waterjet assisted blasthole drilling. The objective of this work was to investigate techniques that reduce the cost and increase the productivity of blasthole drilling. The focus is on a technology that uses a high pressure waterjet to assist the conventional rotary rock cutting action of a tricone drill bit. The potential benefits of this technique are increased productivity, reduced drill bit wear and reduced hole deviation and hence improved quality of drilling. This paper describes the results of a laboratory based experimental program comparing conventional tri-cone drilling performance to the proposed waterjet assisted approach. Additionally, work has been completed looking at the more practical issues around the collection and sampling of drill cuttings and water recovery (recycling) when drilling with a waterjet. These studies have demonstrated that waterjet assisted drilling can significantly increase the rate of penetration over conventional rotary drilling. For the best-case experimental result, the relative improvement was over 40 per cent. More importantly, it is a starting point for examining alternative uses of the additional drill productivity obtained from waterjet assisted drilling. For example, increased drill productivity could be used to improve rock fragmentation by drilling a tighter blasthole pattern in the same time period. an existing drill fleet, then the drill fleet size could be reduced, or improved rock fragmentation could be achieved by drilling a tighter blasthole pattern within the same time period.

Jan 1, 2004

By A. Angelov, U. Peukerd, S. Gaydardzhieve, A. Stefanov, K. Grossman, V. Stoilov

Flotation concentrate originating from the Asarel-Medet porphyry copper mining and processing complex in Bulgaria has been subjected to regrinding using a Ro-Star mill; the effects of which on the downstream metallurgical behaviour are discussed. Particularly the effect on the liberation degree was studied through an optical microscopy and MLA-SEM automated mineralogy. On the other hand, copper selective flotation of the reground bulk concentrate was realised to evaluate the anticipated metallurgical improvement. Process parameters such as involvement of prior hydrocycloning and variation of collector dosage have been evaluated. Within a two-minute residence time inside the Ro-Star mill, an improved liberation degree of the copper bearing minerals has been observed. As a consequence, enhanced copper recovery and selectivity against pyrite was noted. It has been found that in order to guarantee efficient flotation of the resulting ultrafine particles, a modified flotation regime (i.e. changing collector suite and dosages) should be followed. Keywords: RoStar Mill, liberation, flotation recovery, ultrafine particles

Jan 1, 2020

By Janne Kauppi, Kaj Jansson, Piia Suvio, Saara Hagnäs

"Historically the focus at the mineral processing sites has been to improve the production operations, while little focus has been set on how factors, such as the quality of water used in the process affects the metal recovery. Simultaneously increasing public pressure and water scarcity is driving the mining industry to recycle more water back to the process, which in turn leads to accumulation of impurities within the recycled water. This paper presents a concept for a systematic approach on targeting the impurities that have a negative effect on the metal recovery at the flotation circuit by using a novel solution called Process Water Recycling Plant (PWRP). These plants are designed with specific ore type in mind. PWRP produces cost-effectively process water to different target qualities, especially for flotation purposes enabling higher and more stable flotation recovery. It consists of pre-designed and standard water treatment units for a wide range of volumes. The application-specific configuration of units is governed by the water quality requirements, and can be designed according to specific customer needs. Testing has been carried out in order to investigate, which recycling water impurities affect the different ore types and how the metal recovery in flotation is affected as a consequence of the poor-quality water. The results indicate that every ore type is impacted differently and without a good understanding on how the water quality impacts the process performance, adverse effects on the flotation recovery can occur.INTRODUCTION With a focus on where water is used within the mineral processing, it has become evident that even though water is used in several different processes, majority of the water losses within the site occur at the tailings processing and the tailings storage facility. New tailings management technologies that can increase the recovery of water are actively being developed, but the key to improving the efficiency of water use and reducing the operational risks lies in closing the water loops and increasing the slurry density in the tailings processing. With this shift from conventional tailings technologies towards paste and dry stacking, water efficiency is vastly improved, but it might in turn lead to process water challenges with impurities, reagents and fines being recycled and accumulated within the production processes."

Jan 1, 2018

By C. J. Newman

Production levels at the Kidd Creek copper operation increased during the 1980&apos;s by expansion of both the smelter and refinery and by major modifications to equipment which was causing bottlenecks. As a result, there was a significant reduction in the unit cost, some manpower reductions and hence a significant increase in productivity. In the last two or three years, there have been no major expansion projects leading to unit cost reductions and yet these have still been attained. This has been achieved by the development and implementation of various techniques designed to maximize the inherent potential of the operators and maintenance employees. This paper will initially describe the operation but will then place emphasis on employee involvement through such methods as idea awards, incentive schemes, loss control and continuous improvement programs. Organizational changes are discussed, particularly with reference to changes from the traditional operator role to one which encompasses maintenance skills and to cross-training of maintenance employees into multi-discipline fields. The effect of these changes are discussed by a review of the salient plant parameters of safety, production levels, cost and quality.

Jan 1, 1993

By Edward C. Mabbs

U.S. industry must increase its productivity or lose its competitive position in the rapidly expanding and inter-dependent world markets. Recent improvements in material handling techniques and equipment, coordinated with production processes, provide one of the greatest opportunities to increase productivity. Successful managers must learn how to take advantage of these material handling opportunities to gain competitive position.

Jan 1, 1973