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By C Muñoz, N Ortega, J Vergara, D Avilés

Mass blasts have been the subject of extensive studies because of their potential benefits in mining operations. However, it has not been possible to advance due to the paradigm that states that the blasts near the designed final wall or to critical structures have to be low tonnage. Another reason is the absence of specialised simulation programs to more precisely determine the influence of the energy released by blasting to the rock mass. There are some studies that demonstrate the possibility of massive blasting that maintain the design of the final slope (Farias and Santander, 2014). It should be noted that these studies develop the concept that the size of the blast should not increase the peak vibration in the rock mass.The study was carried out in partnership with Los Colorados Mining Company. Analysis, reconciliation and wall control for two types of blasts were performed:blasting production: approximately 850 000 t, with special wall control considerationsblasting of approximately 950 000 t over the entire width of the bench.Monitoring systems were used in the near field and far field using examination of holes in order to obtain information to assess the impact on the rock mass and then to compare these to conventional blasting combining production and contour blasting.The results show that for a large blasted volume, production and/or those generated from toe to crest on the bench did not produce more impact in the rock mass than the conventional blasting.The conclusions drawn from this study are:an improvement in the excavation rate of 7500 t/h that is higher than the maximum rates normally obtainedthe peak vibrations of the P wave generated by both blasts did not exceed the peak particle velocity criteria (Vergara and Muñoz, 2014)holes examination indicating no difference in their entire length, in pre- and post-blast reviewover US$2 000 000 savings generated in the year (estimated by the client) (Avilés, 2014).CITATION:Vergara, J, Muñoz, C, Ortega, N and Avilés, D, 2015. Benefits related to applications of a mass blast in open cut mining, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 625–632 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By E S. Weiss, S P. Harteis

The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) has conducted full-scale explosion experiments, to evaluate the strength characteristics of various seal designs, used for safely isolating worked-out areas in underground coal mines. Large-scale explosion tests conducted within the multiple entry section of PRLÆs Lake Lynn Experimental Mine (LLEM) is currently the only accepted test method used by the Mine Safety and Health Administration (MSHA), for deeming a seal design suitable for use in American mines. These explosion tests are labour intensive, expensive to conduct, and can interfere with other critical underground safety and health research programs conducted by NIOSH. The PRL has developed an alternative seal evaluation method, based on a hydrostatic pressure loading concept, that can facilitate the in situ testing of seals in an operating mine. Two chambers within LLEM and one within PRLÆs Safety Research Coal Mine (SRCM) were used for hydrostatic pressure loading various seal designs. The results from these chamber tests compare favourably with those from the large-scale explosion tests in the multiple entries. In addition to testing seal designs at the required 20 psi static pressure level, the chamber test approach also allows for the determination of the sealÆs ultimate design strength. Size-scaling relationships for predicting the strength of seal designs as a function of entry size are also presented.

Jan 1, 2005

Several new techniques. which may be applied with advantage to the search for uranium are described. Scintillation type gamma spectrometers are now available for airborne', ground and borehole use. These can distinguish in a broad way between anomalies due to uranium, thorium and potassium. Gamma spectrometers based on semiconductor detectors now under development should be capable of much greater resolution. These should also make possible rapid, accurate and cheap radiometric analyses of samples containing uranium and/or thorium, whether in radioactive equilibrium or not. Another valuable prospecting aid, particularly in areas of tropical leaching, is systematic sampling of soil for radon content. Equip- ment for this purpose is currently available and it will be possible to extend the method when development of an alpha probe suitable for use in deeper holes is completed. Variations in the concentration of certain trace elements'in soil (e.g. mercury) also offer promise in the search for mineralized zones which may contain economic eon¦- centrations of uranium.

Jan 1, 1968

By Flann R. C

A small modification to current industrial practice should lead to better nickel powders for use in alloying, electroplating, and powder metallurgy. Nickel powder compacts sold for alloying are not always suitable for electroplating applications, since some presently used commercial powders will expand on sintering. Further, such nickel powders are unsuitable for use in the production of powder metal parts, because of expansion during heating of the near-net-shape preforms. Research in these laboratories has enabled the elimination of expansion, and led to techniques for the production of compacts suitable, in particular, for commercial use in both alloying and electroplating. The techniques include: powder pretreatment, cold pressing and sintering, hot pressing, and hot pressing and sintering. In this way compacts are readily prepared with densities of at least 93 per cent of solid nickel, and these, when used as anodes in Watts general purpose and bright baths, give both cathode current and plating efficiencies of 90-98 per cent.

Jan 1, 1979

By C Laming, P M. Hetherington, F A. Pym, M P. Murphy, K E. Crook

Reconciliation is a powerful tool used by mining operations to compare the mass and grade of ore produced with what was estimated before mining. The primary objective of reconciliation is to verify that the estimated planned metal production is achieved during processing, allowing issues to be identified for which adjustments can be made throughout the mining value chain to improve recovery and maximise efficiency. Traditionally, the mine plan is based on estimated mine grades using sampled exploration drill hole or blasthole grades. Reconciliation discrepancies between the mine plan and mill are common due to such factors as insufficient or non-representative sampling, poorly conceived models, or unrecognised blast movement. MineSense Technologies Limited® (MTL) has developed an X-ray fluorescence (XRF) sensor-based ore classification system that is installed on mining equipment to provide real-time grade estimates of run-of-mine material at bucket, truck, or belt-scale. Bucket level grade estimates provide insights into grade variations at the mine face that were never before available. This data set eliminates some of the leading causes of reconciliation discrepancies and enables tracking of tonnages and grades from the mine face to the processing plant at bucket resolution with confidence. Bucket-by-bucket grades at the mine face enable dynamic optimisation of the mine plan to stabilise the mill feed grade through blending of mine and stockpile loads. Beyond stabilising feed grade, Mine to Mill reconciliation combined with the full XRF spectrum response can generate proxy relationships to ore characteristics like hardness and recovery. These properties can then be predicted at the mine face, enabling further optimisation of the downstream mill feed, not only for grade, but also for power and water consumption, reagent addition, and recovery. This paper presents the benefits of MTL technology for grade reconciliation and mill performance optimisation at a Cu Mine in BC (Canada).

Mar 22, 2022

By I Govender, T L. Moodley

Tumbling mills are grossly inefficient, using only 5 per cent of the total energy supplied for actual breakage. A significant proportion of this inefficiency is unavoidable owing to geometric limitations; rotating drum systems are prone to exhibiting certain regions (energy barriers) that resist particle entry thereby restricting the transfer of energy. Though such systems are inherently inefficient, improved modelling schemes may lead to slightly enhanced efficiency through better microscale predictions of key breakage drivers (stress, force). Central to achieving such incremental advances is the development of a universally accepted rheology for dense granular flows. Armed with a better understanding of these macro-scale ingredients, classical process modelling offers an efficient, spreadsheet friendly framework for recovering the spatial distributions of the comminution drivers. At this real-time level of process control, it should be possible to tune comminution operations towards more energy efficient configurations – the ultimate goal of this research. The present work employs validated DEM data to recover the full continuum field which will ultimately serve as a basis for calibrating process model outputs based on different rheological hypotheses. Such a continuumbased approach captures tensor properties like the shear stress and strain rate – both of which are necessary to developing a dense granular rheology. Moreover, DEM captures this data at the momentum transfer timescale of 10-6 s – no other measurement technique is capable of this level of spatial and temporal resolution. Importantly, the confidence in this DEM data is strengthened because it has been validated at the continuum scale using Positron Emission Particle Tracking (PEPT) kinematic measurements. Validated DEM data is derived from batch experiments conducted within a 300 mm ID laboratory drum using three and five millimetre glass beads at 60 and 75 percent critical speed; such mill speeds are typically encountered in the tumbling mill industry. Dimensional analysis is conducted using critical rheological parameters (shear rate, shear stress, granular temperature etc), which are key to not only developing a granular rheology but ultimately will be used to tune our mechanistic models.

Aug 24, 2022

By P K. M Mazzoni, D Frantois-Bong

This paper aims to show alternatives to the estimation methods used for finding the parameters in GyÆs well known model for sampling variance in the case of particulate materials. Many experiments designed for gathering data on the sampling variance for specific mineral deposits allow the experimenter to use approximations in the calculation of the parameters of the mathematical model involved, which sometimes can be very useful. However, there are some instances where approximations lead to biased estimates of the parameters, and consequently, lead to errors in the establishment of the sampling protocol and treatment of quality control data. In the present work, an alternative is presented for computing the parameter values based in any experimental set up, without the need for any simplification. The method was derived using the method of least squares and evaluations are made using the usual tools in this kind of methodology: residual analysis and evaluation of the fit by means of a plot of calculated versus experimental variances. With the aid of these tools, one can better evaluate the structure of the experimental errors in such applications, and the adherence to the proposed model. In addition, it is possible to perform hypothesis testing for the equality of different sampling procedures in terms of sampling variance. The full mathematical details are given, together with an algorithm for applying the method, which can be implemented easily using any computer language. An illustration of the method is shown, considering the international work done in ISO/TC 102. This example is a determination of the minimum sample mass to be collected in iron ore shipments, in order to achieve a specified sampling precision.

Jan 1, 2005

By Willis G. M

Preliminary experiments have shown that, when used in a fusedchloride electrolyte, titanium carbide anodes dissolve yielding lower titanium chlorides which nlay be electrolysed in situ to produce a cathode deposit of pure titanium metal. The anode residues are easily withdrawn from the cell. Further experiments have established the operating conditions for maximum efficiency in the process.The process is essentially two-stage, viz.: (1) titanium carbide production, (2) electrolysis producing metal. Power requirements appear to be moderate and this fact, combine·d with the simplicity of the process make it attractive as a possible method for the production of titanium.INTRODUCTIONDue to the high reactivity of titanium and its, affinity for oxygen and nitrogen, the extraction of this metal generally involves the use of halide. compounds as intermediates. For instance, magnesium reduction of titanium tetrachloride is the basis of the well established Kroll process and electrolysis of the lower chlorides in a molten salt bath has been proposed by Cordner and Worner (1951, p. 358) and others (Brenner and Senderoff, 1952, 223C; The TitaI Company (Inc.), 1952) as means of production of the metal. Thedifficulty of preparation of these compounds prompted a search for an alternative extraction process. The fact that aluminium, an equally reactive metal, has been prepared by electrolysis using aluminium alloy anodes suggested the possibility of a similar process for titanium production.The Titan Company (Inc.) (1952) has patented the use of crude titanium metal anode, but it was thought possible that a metallic compound, such as the carbide, could be used for this purpose. Although Lorenz and Kaufler (1909) suggested the use of carbide anodes for metal production, no...

Jan 1, 1956

This session comprises six papers: One paper is specifically on advances in drilling techniques, a paper presents a classification for water inrush rich with corresponding guidelines for protection, two papers are concerned with mining impacts in integrated catchment management - one from the quality viewpoint and the other from the quality viewpoint, and the final two papers are case studies of mine dewatering - one for an underground mine threatened by a karst limestone aquifer and the other of an open-cut mine threatened by interbedded sand aquifers. The paper entitled, Practical mine dewatering by means of surface drilled wells by Sides is innovative in presenting the case for wells as cost effective and appropriate for a number of purposes including exploration, re-opening old mines, dewatering, grout emplacement and monitoring.

Jan 1, 1988

A new concept central to the search for sample correctness is presented. In spite of its simplicity, this concept has already unknowingly formed the implicit basis of already established, current limiting rules of use for certain types of samplers, used as mere examples in this paper. Once explicitly enunciated though, this fundamental principle gives immediate, simple and new practical rules for the design of predictably correct sampling equipment and for sampling device auditing. Examples of application are offered as an illustration, including an earlier, important, albeit unpublished, idea found in Pierre GyÆs earlier works.

Jan 1, 2005

By B Stewart

It has long been recognised that knowledge of the conditions existing in a mine after an incident is essential in deciding whether to deploy responders as part of the incident recovery process. Applying this knowledge in a structured manner to the assessment and the acceptability of the risks likely to be faced by those teams during response activities before authorising their deployment is an onerous task incumbent upon the person controlling the incident response. The Mine Event Management System (MEMS) provides structure and coordination in the management of mine events. It assists with the skills and knowledge for incident control teams to effectively manage any emergency or non-emergency event, be it large or small. In cases where multiple organisations are involved, the MEMS promotes effective joint operations through the use of common terminology and structure to provide seamless communication between agencies at all operational levels. The SQL-based software developed by Queensland Mines Rescue Service (QMRS) assists decision-makers to make considered options; it does not make decisions for you. When set-up, it allows the information that already exists within a mine’s Safety Health Management System that is relevant to the incident to be accessed and considered rapidly within the pressured environment of an emergency. Additionally, the incident specific questions contained within MEMS focuses the management team on gathering and assessing information relevant to the incident as it progresses. The software’s event log can be utilised as an auditable document for post incident investigation. The MEMS provides a process to properly consider the adequacy of the information available upon which decisions have to be made, to consider and acknowledge the hazards of the environments within or adjacent to which responders will need to work and to acknowledge and authorise the entry of responders into or to remain within a mine either during or post an incident occurring, once an acceptable level of risk is achieved.

Apr 16, 2024

By R Gaze, J Horton

Block models generated with all linear interpolation algorithms contain inherent smoothing that typically results in an underestimation of grades and overestimation of tonnes in resource estimates. For mineral deposits that are anticipated to be exploited by underground mining methods excessive smoothing may result in materially misleading estimates of Ore Reserves. To account for smoothing in the open pit mining environment recoverable reserve techniques such as indicator kriging and uniform conditioning are employed to provide non-spatially located proportions of the large blocks above the cut-off grade. These models are not suitable for underground mine planning where the actual location of material above cut-off is required to design its extraction. To correct for excessive smoothing it is proposed to modify the ordinary kriged block estimates a posteriori using an affine correction with a local variance adjustment factor. The proposed methodology is demonstrated for a base metal deposit during a feasibility study.

Jan 1, 2009

By D Pepper

Despite the limited literature regarding the pressure filtration of mine tailings (compared to the large number of papers published each year on paste thickening of tailings) the number of mines dry stacking filtered tailings is approximately equal to the number of mines storing tailings in paste form. Main drivers for filtering tailings are: water recovery, future rehabilitation costs for tailings storage area and permitting requirements. In arid climates, the cost and scarcity of water justify the capital and operating costs associated with pressure filters. Further justification for filtered tailings is the potential for progressive reclamation of the dry stack, which can proceed earlier and faster than the reclamation of a tailings dam.Filtered tailings must be transported to the storage area by trucks or conveyors. For dry stacking, 70 - 80 per cent solids content (by mass) is typically acceptable, however the primary goal is to provide a filter cake that is consolidated and dry enough to prevent bridging and build-up on the materials handling equipment. It has been observed that high average solids contents (~70 per cent) can be achieved while the centre of the filter cakes is still wet and sticky, presenting challenges for the transportation of the solids. Appropriate controls must be in place to ensure consistently easy to handle solids are discharged from the filter.FLSmidth has installed two fine coal tailings dewatering systems in the United States. One of these systems incorporates a Deep Cone Thickener« upstream of the filter press to minimise the amount of water that must be filtered, while the other tailings filter press is fed by a high rate thickener. The operation and performance of these filters is discussed and compared to the lab testing used to size the full-scale equipment.CITATION:Pepper, D, 2012. Operation of filter presses for tailings dewatering, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 241-246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By J Greberg

This paper discusses the use of simulation in the mine planning process. A case study on the Newcrest Cadia East project is presented, and the challenges and possibilities for using simulation as a tool for mine planning and scheduling is discussed.The simulation study presented in this paper was performed during the project’s prefeasibility stage, and focused on the planning and scheduling of the development of panels in the future mine. The Cadia East project will be the largest underground operation in Australia and the first using panel caving. Simulation was used in order to optimise the development of panels; it was mainly used in order to verify the plans for the development process and allocate resources in an optimal way. The work was performed as an iterative process and adjustments to the plans were made according to simulation results. Bottlenecks were identified and different scenarios were tested.The results from the simulation study shows how different operational constraints affect the planned development process and how changes in priorities can be necessary in order to maintain a high development speed. Furthermore the study shows how changes in planned mine layout requires changed strategies, and how this was solved using the simulation tool.In this paper the authors critically discusses the use of simulation in mining operations: what are the limitations and challenges of using simulation as a tool for mine planning and scheduling, what are the benefits, and what do we aim for in the future?

Nov 22, 2011

By S K. Michelic, M Schickbichler, A Kharicha, E Karimi-Sibaki

The requirements for the controllability of metallurgical processes are increasingly becoming the focus of both industry and research. Advances in this field of research not only impact the stability of processes but often also influence the quality of the final product. One important way to examine processes in-depth, and thus show potential for improvement, is to describe them using physicsdriven models. In metallurgy, thermodynamic and kinetic descriptions of interactions between individual components of a system are often used to describe and analyse important metallurgical phenomena across the entire process. However, for the creation of physics-based models, boundary conditions and process variables must be implemented to enable a description that is as realistic as possible. The collection and generalisation of boundary conditions and process variables is, therefore, an important step towards functional models. The focus of this study is the determination of mass transfer coefficients between all components in a steel/slag/refractory system. For this purpose, experimental and theoretical methods are applied. Laboratory scale experiments are carried out in an induction furnace, and the mass transfer coefficients of the defined steel/slag/refractory system are calculated from changes in the chemical composition of the various components. Additionally, a calculation of the mass transfer coefficients based on dimensionless quantities is carried out. By comparing the values of the mass transfer coefficients determined theoretically and those determined experimentally in the trials, the suitability of the calculation is examined. The collection of mass transfer coefficients provides essential findings for future kinetic descriptions of inclusion modification based on the effective equilibrium reaction zone (EERZ) approach.

Aug 21, 2024

By Shuguang L, Jing S

Computer controlled truck dispatching systems is a newly-developed technical system in surface mines with shovel-truck technology. The real time dispatching criteria, as the core of optimal truck dispatching software, are analysed and a new criterion, complex dispatching criterion, is put forward. Dispatching criteria previously proposed include: 1. `Earliest Loading' (EL) - to assign a truck to the shovel at which the truck can be loaded earliest. 2. `Max Truck' (MT) - to assign a truck to the shovel at which the truck will have the shortest waiting time. 3. `Max Shovel' (MS) - to assign a truck to the shovel which has been waiting for the longest time. 4. `Minimum Saturation Degree' (MSD) - to assign a truck to the shovel at the branch where the truck flow saturation degree is minimum. 5. `Minimum Saturation Degree with Truck Cycle time consideration' (MSDTC) - as the MSD principle, with the truck travel cycle also considered. 6. `Fixed Dispatching' (FIX) - to assign trucks to fixed shovels. A system simulation model has been set up for truck dispatching system analysis. A few surface coal mines have been selected for case studies. Equipment waiting times and shift production of the system are obtained as the main outputs of the model. Simulation results show that each dispatching criterion has its own applicable range, no one can absolutely dominate the others. For example, when under-trucked, EL and MT criterion can obtain higher production than the MS criterion; when over-trucked, it is vice versa; while for MSD criteria, better results can be obtained no matter how the truck numbers fluctuate. From the view point of shovel output balance, large fluctuations occur for EL and MT criteria, while a good balance can be obtained for other criteria. In the light of dynamic change of mining system conditions, a single dispatching criterion is not necessarily reasonable. A complex dispatching criterion has been put forward to seek the complex optimum effect. Taking the advantage of each dispatching criteria, the dispatching result of a complex dispatching criterion dominates over individual dispatching criterion and a comprehensive optimum effect can be reached.

Jan 1, 1995

Selection of the mining method and most appropriate mine layout for deep open cut coal mines is discussed, giving particular attention to the types of mines expected to be developed in the future in Australia. Because of the more complex nature of these operations a large number of alternatives for mine design are available, and the constraints associated with these designs are discussed. Potential problems to be overcome are identified to allow setting of realistic targets for maximum output and build-up production rates.

Jan 1, 1981

By Bourgeois F

The population balance concept has provided a useful framework for the description of the operating behavior of the ball mill. This approach finds expression in the so-called selection breakage function model for batch and continuous mills. This model produces very good descriptions of the size distribution of the products from ball milling operations and the model is very useful for the description of batch and continuous mills and, when combined with models for classifiers and other unit operations, provides a solid basis for flowsheet simulation procedures. The breakage and selection function model is essentially descriptive and not predictive because the parameters in the model cannot as yet be related to the fundamental material properties of the material that is broken and to the fracture mechanics that govern the comminution of brittle particulate material during the rapid impact and compression events that occur with high frequency in a ball mill. The population balance approach smears over the individual processes and regards the ball mill as a continuum with breakage occurring continuously in time and space. New experimental techniques, particularly the adaptation of the Hopkinson bar as the ultrafast load cell (UFLC) to the problem of observing the extremely rapid impact fracture of particulate solids, have made it possible to make accurate and consistent measurements of particle strength, particle fracture energy and the single-impact breakage function. These quantitative measurements have been incorporated into a new conceptual model for the description of the ball mill. The model is based on identifying all events that give rise to particle breakage, and using the fundamental experimental data obtained on the UFLC and other single-particle fracture tests, the probabilities of these events can be independently determined. The distribution of impact energies that occur in the ball mill has been established by discrete element simulation of the media motion. The probabilistic description of the individual fracture events and the distribution of impact energies are combined to make a priori predictions of ball mill performance under a variety of operating conditions. The new model is used to calculate the selection and breakage functions for quartz in a small batch mill.

Jan 1, 1993

Over the past few years, there has been an emerging relationship between business and civil society, especially NGOs. This relationship has the potential to bring about significant change, identifying common ground between commercial and societal interests. The mining industry has been a leader in acknowledging the need for community consultation and engagement. This paper argues that partnerships can make a very significant contribution to the industry as it comes to terms with the dilemma of an open economic system pushing against a closed ecological system.The paper will pose a number of questions: where is the locus for debate about sustainability in the mining sector?; how well embedded within companies are the new competencies that Leon Davis first identified in 1995 for the mining sector?; how has education for mining engineers or exploration geologists changed to prepare people for what are very different expectations within the working environment?; how well is the industry doing in managing its own environmental impact and what is its responsibility to an agenda for sustainability which extends beyond its own operations?;and how can NGO partnerships contribute to more sustainable outcomes? The paper does not aim to answer these questions, but to explore them in the hope that the issues and possibilities raised will contribute to advancing progress towards sustainability within the industry.

Jan 1, 2002

By P Thompson, B W. Atkinson

Water treatment is not æcore businessÆ for mining companies.Just as mineral ores and coals are unique, each requiring detailed characterisation and pilot-testing to determine their optimum beneficiation route, so too are mine waters, each requiring careful assessment to determine the most appropriate treatment. There are many cases of æregret capitalÆ expenditure, whereby mines have installed off-the-shelf equipment only to find it inadequate for their purposes or grossly expensive and labour intensive to operate.Water may be required for potable purposes, ore processing, dust control and/or irrigation. A major driver will frequently be environmental constraints for off-site discharge. Mine water projects can become very complex, and detailed models need to be prepared and optimised to properly consider the raw water sources, the on-site storages, the on-site uses and the off-site discharges, as well as handling the residuals (by-products) of water treatment. By-products may be in the form of concentrated backwash streams or streams of elevated salt content. Careful management of the by-products is required to avoid recontamination of the source water.Regulators often drive mine owners toward reverse osmosis (RO) so that their discharges can be considered as æzero dischargeÆ in terms of potential pollutants. Such decisions need to be based on site-specific information rather than any form of æblanketÆ requirement. An analogy is that many humans like to consume mineral water rather than ænormalÆ tap water. Receiving environments also accommodate or even prefer their æmineralsÆ and so RO is neither warranted nor sustainable in many cases.This paper presents two case studies for operating mine sites, both of which have a significant excess of water requiring environmental discharge. The examples demonstrate a sensible balance between treatment type, environmental constraints, process implementation and residuals management. LIMN« æthe flow sheet processorÆ was used to model one of the case studies due to the complexity of the water system on that site.CITATION:Atkinson, B W and Thompson, P, 2013. Mine water - optimising for site and environment, in Proceedings Water in Mining 2013 , pp 9-14 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013