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By Paulo Couceiro, Juan Navarro

The impact of rock blasting fragmentation and heave on digging performance in open-pit mining operations is usually the first true indicator of blasting outcomes. Within the typical excavation cycle, the bucket loading time or instantaneous digging rate are the ones that present the strongest correlation with rock fragmentation size distribution, swelling, and shape of the muckpile, a part of rock mass hardness, equipment size, power, and others. As the efficiency of unit operations becomes increasingly important for long-term mining strategies, cost-effective approaches are needed to increase mine productivity. In this line, the performance of downstream operations, such as digging, hauling, and comminution, may be affected by the energy input in blasting. This requires a better understanding of the explosive’s energy role in such unit operations in order to drive consistent improvements. Therefore, this paper examines the impact of the explosive’s energy distribution on shovel diggability from production shots carried out with different explosives in an open pit gold mine, with the aim of modelling the interface between blasting and excavation.

Jan 21, 2025

By Paul L. Wichlacz

A mathematical model of growth and ferrous iron oxidation for attached bacteria was applied to rotating biological contactor (RBC) units treating acidic mine drainage. The model describes attached bacterial growth as a saturation function, where the rate of substrate utilization is determined by a maximum substrate oxidation rate constant, a half saturation constant, and the concentration of substrate within the RBC. The maximum oxidation rate constant was proportional to flow rate and the substrate concentration in the reactor varied with influent substrate concentration. The model was tested at three separate sites and with three different size RBC units. The ability of the model to predict the rate of iron oxidation under all test conditions was significant. The accuracy of the model was found to be affected by unit size and vary with specific test site.

Jan 1, 1985

By K W. Mills, N R. P Baczynski, J Mylvaganam, D A. Prado, M F. Lee, I A. de Bruyn

"This paper presents the second part of a study of the assessment of rock stress inputs on the performance of various new mining designs at the Ok Tedi large open pit mine in Papua New Guinea. Over the years, four programs of rock stress measurement have been completed at Ok Tedi, each providing different interpretations of the in situ field stresses. Details of three of these programs and interpretations are provided in the precursor to this paper, entitled ‘Rock Stresses at Ok Tedi, Papua New Guinea’ (Lee et al, 2014).This paper explains how the various stress interpretations were utilised in the modelling of the proposed new open pit and underground mining excavations, comparing where possible their expected effects on stability. The modelled performance of three specific mine components have been discussed here as case studies, including: the below-pit drainage tunnel, as the floor of the open pit workings is mined down from 350?m above, to within just 75?m above the crown of the tunnel the stability of the 1000?m high slope of the proposed West Wall cutback the proposed sublevel open stoping extraction sequence in the Gold Coast orebody beneath the East Wall, for which only the likely ‘worst-case’ stress regime was used to assess sequencing and stability issues.The benefits of scheduling the collection of detailed rock stress measurements and other input data from a range of different sources at various stages of the projects are discussed.Alternative in situ stress models have less stability impact on open pit slopes than on underground mine excavations.CITATION:de Bruyn, I A, Baczynski, N R P, Lee, M F, Mills, K W, Mylvaganam, J, and Prado, D A, 2014. The application of rock stress inputs to stability assessments at Ok Tedi Mine, Papua New Guinea, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 43–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

Real economic growth for 1988 may fall short of the 3.3% projected by the U.S. Department of Commerce in August 1988 be-cause the summer drought and intense heat in many areas curtailed output more severely than expected. The economy grew at an average annual rate of 3.0% for the first three quarters of the year, slowing in the second and third quarters. Export growth, which occurred even as the dollar edged up com-pared with other industrial country currencies, was an important factor in the expansion. Notable gains were posted in sales of machinery, computers, aircraft, chemicals, and telecommunications equipment. Imports increased, but not as much as exports, and the U.S. trade position was still much improved from that of 1987. Personal consumption expenditures grew slightly faster than the economy as a whole. Purchases of consumer durables showed notable strength in the first half of 1988, but slowed down in the third quarter. [ ] Despite the moderate rise in interest rates, business spending for new plant and equipment also rose and contributed to 1988 gross national product (GNP) growth. Both new business investment and export demand spurred orders for U.S.-made machine tools. Orders for machine tools for the first 8 months of 1988 were almost triple those for the corresponding period in 1987.

Jan 1, 1988

By Ali Montaser

Hauling trucks are important part of equipment fleets for large earthmoving operations such as those encountered in dams and highway construction projects. This paper presents an automated methodology for tracking and estimating productivity of hauling trucks fleet operations in near-real-time. Recent advancement in automated site data acquisition technologies made their use in tracking and monitoring of construction operations feasible. However, these technologies fail to track hauling truck fleets due to the change in the cut and fill locations from one cycle to another; making tracking and progress reporting difficult and inaccurate. In addition, there is very little work done utilizing data sensed directly from equipment, for example sensing when truck dumping bed is raised during the dumping process. The technologies deployed in the developed method are Radio Frequency Identification (RFID) and equipment control sensors. Low cost passive RFID tags are attached to hauling trucks and fixed RFID readers are attached to loaders or excavators. The read range of the used RFID tag is centimeters, to be activated only when a loader with an attached RFID reader is loading a truck. On the other hand, control sensor is connected to the truck control system and operated by the motion of its movable bed. The function of control sensors is to record the signal time when the truck operator gives order to the truck control system to raise or lower truck bed. The captured data is then transferred wirelessly from the RFID reader and control sensor to a computer housed in one of the temporary offices onsite and subsequently to the main server in the contractor?s head office. Fusing the data captured from RFID reader and control sensor is used to identify loading, travel, dumping and return time that constitute the hauling truck cycle time. The collected data is analyzed and processed automatically, without human intervention, to calculate the productivity of the hauling truck and to report it directly to onsite personnel. Relational database is developed to support the implementation of the proposed method. The developed database is used to process the data captured by the RFID and the control sensor to calculate the productivity achieved in cutfill operations in near-real-time. The developed methodology is expected to facilitate early detection of discrepancies between actual and planned performances.

Aug 1, 2013

By Kotaro Ogura

"Ethylene has been produced in aqueous solution from CO2 by the electrochemical reduction driven by a natural energy. This process is useful for storing a large amount of the natural energy. In the closed system, the conversion efficiency of CO2 is almost 100%, and the maximum selectivity for the formation of ethylene is more than 70%. On the other hand, the current efficiency for the competitive reduction of water is less than 10%. The electrolysis is practicable under such special conditions as three-phase interface consisting of gas, solution and metal, concentrated solution of potassium halide, low pH and copper or copper halide-confined metal electrode. These requirements are thoroughly examined, and the grounds to reply upon are revealed. A series of chemical apparatuses including an electrolytic cell in a large scale are designed for the ethylene production, which allow us continuously to supply raw CO2 and to extract the product.IntroductionIn connection with the depletion of the petroleum reserve, much attention has been paid to the utilization of natural energies such as sunlight, wind force and waves. However, these energies are always changeable, and some means of storing them are necessary for the common use. In general, natural energies are transformed to the electric energy at the time of utilization, but the electricity is not very storable. This is one of the reasons why the application of natural energy is not so expanded. On the other hand, the storing of natural energy by plants is very skilful. In the photosynthesis, solar energy is transformed to chemical energy by fixing carbon dioxide."

Jan 1, 2009

By T Ireland

The Rosedale Outfall Project utilised an earth pressure balance (EPB) tunnel boring machine (TBM) for only the second time in Auckland. Although the tunnel was excavated fully through East Coast Bays Formation (ECBF), the downhill gradient along with some unexpected areas of extreme water posed some significant challenges during construction.The Rosedale Waste Water Treatment Plant Outfall Tunnel project was commissioned in response to the growing needs of North Shore City, New Zealand. The outfall tunnel comprises a 3 km long segmentally lined tunnel and a 2.1 km buried marine pipeline, and discharges 2.7 km offshore. The capacity of the new outfall is 6 m3/s compared to the existing outfall capacity of 1 m3/s.Following previous project experience, and with the tunnel located along its full length in the bedrock weak sandstone/siltstone bedrock of the East Coast Bays Formation, tunnelling conditions were expected to be benign. However during construction six high inflow events were encountered, including a full face (3.4 m diameter) of Albany Conglomerate over a 48 m length of tunnel. This material comprised cobbles in an uncemented sand matrix, and inflows were recorded at over 25 L/s.This paper describes the design challenges on the project including the design of a steel fibre reinforced segmental lining for internal pressures. The specification of the machine is discussed including the modifications required to enhance the risk mitigation measures already in place. The ground conditions encountered are discussed and have improved the knowledge of the range of conditions that can be expected in Auckland.Despite the challenges presented during construction, excellent progress rates were achieved and the tunnelling was successfully completed ahead of program.

Mar 8, 2011

By Bo R. Arvidson

The strongest magnetic roll separator available on the market enhances certain industrial minerals purity to levels not reached previously. Exceptionally strong forces can also be utilized for processing relatively fine particles at feed rates several times greater than for prior art electromagnetic induced roll separators. Since the unique machine does not work with an air-gap, coarser particles than what has been considered practical can be separated at rates up to 20 tph per single machine unit and 40 tph for a double machine unit. Examples for all these three application areas will be given. While the roll separator can be used only for dry processing presently, the other new separator can be used for both wet and dry applications. It is a medium-intensity, high- gradient magnetic separator employing a filamentary matrix. It was primarily developed for recovery of weakly magnetic iron ore fines, but it is finding applications for cleaning of industrial minerals such as wollastonite, calcite, clay and talc. Its main advantage is a simple design resulting in a very lm cost machine both with regards to total capital investment and operation. A significant technical advantage exists also. The metallurgical performance is similar to conventional electromagnetic separators, while the cost per ton is about half of such separators.

Jan 1, 1985

By Richard L. Sanford

The generalized rail haulage simulator described in this paper is an outgrowth of the need to expand a previously developed single level simulator to permit analysis of production problems where intermediate car storage is used. Many of the ideas of the former single level simulator, which is an integral part of an Underground Generalized Materials Handling Simulator (UGMHS), have been used in model development. In addition, experience gained in applying the earlier model to a variety of operating conditions has been heavily relied on. The generalized rail haulage simulation model can operate as an independent system and, as such, can be used to analyze rail haulage systems using production distributions as data input. In addition, this model is designed to replace the present rail haulage sub-assembly in the UGMHS model and the linking procedure has been integrated into the model. The flow of coal from production sections in UGMHS, for example, fill the mine cars and a condition of no empty cars at a loading station will shut down in by production systems.

Jan 1, 1974

By P Dowd, R Jeuken, C Xu

In Australian coalmines there are a number of coal quality parameters that are measured by analysing samples from boreholes. The data points are used to generate spatial models of these parameters, typically using inverse distance as an interpolation method. Numerous additional boreholes are drilled which have geophysical logs measured downhole but from which no coal quality samples are taken. Full suites of coal quality analyses are expensive and time consuming to drill and sample. If geophysical proxies for coal quality could be used, this would greatly improve the accuracy of the resource estimation without additional cost.This paper examines two of the most important coal quality parameters – ash and volatile matter – and assesses the results of a number of geostatistical interpolation methods. The aim is to improve the accuracy of the interpolated models. Auxiliary variables from geophysical logs are also trialled to improve the estimation.A multivariate analysis of ash, volatile matter and several auxiliary variables of a selected coal seam was undertaken in a spatial context, using variography. This was used to construct a model of co-regionalisation that relates all of the variables as manifestations of an underlying geological theme.The traditional inverse distance interpolation approach was compared to ordinary kriging, universal kriging, co-kriging, regression kriging and kriging with external drift approaches. The relative merits of the six interpolation methods were compared by removing all points, one at a time and estimating at the thus known location. The mean error and the root mean square error were evaluated as a measure of bias and precision.This paper demonstrates that there is significant opportunity to improve the estimations of coal quality when using kriging with external drift. For example, the results show that when using the depth of a sample as an external drift variable there is a significant improvement in the accuracy of estimation for volatile matter. Furthermore, when using borehole wireline density logs as an auxiliary variable for ash content, there is improvement in the estimation of the in situ ash. The underpinning reasons for this are discussed in the context of the underlying geology and the physical properties of the coal. These findings hold promise for utilising cheaper proxies for coal quality parameters to dramatically improve data density and the quality of estimations.CITATION:Jeuken, R, Xu, C and Dowd, P, 2017. Improving coal quality estimations using geostatistics and auxiliary variables, in Proceedings Tenth International Mining Geology Conference 2017, pp 157–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

From the mid-1970s ZC Mines at Broken Hill had a policy to increase ore production rates at progressively lower head grades. In the mid-1980s the mine suffered crippling losses at a time of low metal prices. An important contributory factor was the inherent geological distribution of metal grades in the seven defined ore lenses. Grades are bimodal, and perhaps, trimodal, in each ore lens. There is a tonnage deficiency in the critical cut-off grade zone of 7-10% Pb+Zn. Lowering the cut-off grade introduced siliceous and pyrrhotitic material which resulted in significantly poorer metallurgical performance. This example shows that the mine geologist needs to know the grade distribution of the orebody and to convey clearly the downstream implications of changes in the head grade.

Jan 1, 1990

By Bhattacherjee A, Makesh S

Mechanised sub-level stoping is one of the most widely accepted stoping practices followed in base metal mines in India. As a general practice, blast-scheduling of rings in these stopes is done either heuristically or randomly which leads to a high fluctuation in ore grade when drawn and delivered to the mill. In this paper, dynamic programming has been investigated as an optimisation technique for optimal blast-scheduling of rings. A microcomputer based dynamic programming algorithm has been developed in C language which runs under the UNIX environment. A case study based on Indian mine data is presented to demonstrate the application of the dynamic programming concept and use of the developed software. It is concluded that dynamic programming can be used as a production planning tool in Indian mines practicing sub-level stoping and following heuristic/random approaches for blast-scheduling of rings.

Jan 1, 1995

By Carvalho A. Felipe de

The search for environmentally friendly and cost-effective methods for gold extraction has been undertaken in order to provide alternatives to the use of cyanide leaching in the gold industry. Among such alternative reagents is the combination of chloride and hypochlorite ions due to their oxidation of metallic gold and its complexation. Therefore, the current work aims at investigating gold leaching from an oxidized material by means of a solution comprising calcium hypochlorite and sodium chlorite. The sample used in the current research contained 66.1% Fe2O3, 20.4%SiO2, and 35.7 g/t of Au. In addition, XRD and SEM-EDS analysis revealed iron oxide, quartz and muscovite as the main crystalline phases in the sample. For comparison purposes, cyanidation of the oxidized material resulted in 90% gold extraction in 24 h. The reference conditions for the leaching tests with the chlorite-hypochlorite system were: particle size −37 μm, solid/liquid ratio of 10% (w/v), 10 g/L NaCl, 10 g/L Ca (OCl)2, pH 5–6, 3 h of leaching. The effects of the: (i) Ca(OCl)2 concentration, (ii) NaCl concentration, (iii) pHrange and (iv) the effect of pulp density in the extraction of gold were assessed. In addition, the stability of the hypochlorite solutions (OCl−) was investigated. The ideal concentrations of Ca(OCl)2 and NaCl were determined as 25 g/L and 15 g/L, respectively, whereas the optimal pH range was 4–6. Under these conditions, the final gold extraction reached approximately 84%. By varying the solids content of the pulp (10%, 20% and 30%), it was observed that the lower solids value resulted in greater gold extraction (84%). The degradation of the hypochlorite solution and the possible catalytic effect of the presence of the solid were evidenced. To sumup, in the experiment, high gold extractions were achieved in shorter periods of time (3 h), as compared to the cyanidation of the same sample. On the other hand, itwas necessary to use significant amounts of the reagent due to hypochlorite instability at the pH conditions recommended for high gold extractions.

By J. D. Aitken

"DEFINITION OF THE REGIONTHE REGION considered in this paper is bounded on the south by the 60th parallel, on the north by the Beau-fort Sea and Amundsen Gulf, on the east by Archean rocks or by highly deformed Proterozoic rocks of the Canadian Shield (certain weakly deformed Proterozoic strata being regarded as belonging to the Great Plains), and on the west mainly by the Mackenzie and Richardson Mountains.Only the unmetamorphosed strata of the region are considered; that is, the geology of the crystalline basement is ignored.SIGNIFICANCE OF THE REGIONThe region is significant from three points of view -namely, the economic, the scientific and the social. It constitutes 46 per cent of the area of the Western Canada Sedimentary Basin."

Jan 1, 1970

By M Rafty, A Markham, S Atkinson

Australia contains some of the most productive mining areas and is characterised by ancient landscapes and highly variable hydrology. Historical mining of iron ore, coal and other minerals has targeted ore deposits located above water tables, and elevated above creek lines where possible to reduce cost. The downturn in mining caused by falling ore prices over recent years has triggered a drive to reduce cost, maximise yield and delay capital expenditure associated with opening new mines. So as the ore deposits with more favorable mining conditions become depleted there is an increased focus on mining ore associated with valley floors and creek lines. This is demonstrated by a regional assessment of the extent of Channel Iron Deposits (CID) and Iron Ore (Fe) Mines and Deposits in the Pilbara Region of Western Australia (Figure 1). A large proportion of these mines are, or plan to, target high grade CID ore associated with existing creek systems. Figure 2 shows outcropping and inferred sub-cropping CID extents, which suggests there are vast quantities of CID ore deposits throughout the Pilbara Region, intersected by major creeks which could be mined at some point in the future using creek diversions (Atkinson et al., 2017). A similar picture could also be produced for coal mining in Queensland, particularly in areas such as the Bowen Basin.While creek diversions provide an opportunity to maximise the utilisation of these orebodies and extend the life of mine, creek diversions can involve substantial financial, social, environmental and regulatory risks that need to be carefully managed (Markham et al., 2017, Atkinson et al., 2017). This paper discusses the key issues and opportunities associated with diversion decision making. It highlights the importance of using a well-structured assessment methodology that allows key stakeholders to be part of the assessment process and is complementary to material presented in Atkinson et al., (2017). Design considerations for operational and closure designs are presented, as well as mine planning considerations, risks, cost saving opportunities and the benefits of an integrated approach to design. The role technology plays in diversion design and performance monitoring is discussed as are the potential opportunities for the future.CITATION:Atkinson, S, Markham, A and Rafty, M, 2018. Diversion decision making with an integrated approach to design for operations and mine closure, in Proceedings Life-of-Mine 2018, pp 74–79 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

This paper examines the feasibility of combining network modeling and computational fluid dynamics for modeling of underground mine ventilation systems. Both simulation methods have specific advantages and disadvantages for analysis of mine systems. Network modeling is widely utilized by many operations and allows for assessment of current systems and simulation for planning purposes. Alternatively, CFD has been utilized only marginally by operations and is typically a research tool, requiring considerable computational power, complex models, and careful analysis and calibration of results. Network modeling allows for a holistic approach to the ventilation system, giving quantity, velocity and pressure in every branch, but CFD modeling can resolve the flow regime in 2-D or 3-D, which is idea when examination of an area on a more detailed basis is useful, such as dust and gas control. Integration of the two can allow for more flexible systems analysis. The feasibility of integration, along with application to limited underground mine data are examined.

Feb 23, 2014

By Patricio González Santis, Jacopo Seccatore

This paper documents drilling and blasting activities from gold mining in Ecuador and Chile. First, are described the outdated and often non-rational techniques employed by miners, to provide a general framework of the current methods. Then, it is shown what can be improved and how the current methods can be modified. Finally, are shown some field applications and the comparisons of the results obtained

Feb 1, 2020

By H. Herbert Hughes

Iceland spar is a variety of calcite ( calcium carbonate ) characterized by its purity , transparency , and perfection of crystalline structure . It takes its name from the country in which it was discovered . The actual demand for it is small , but the supplies of high - grade optical spar are so meager that the search for it has become international in its scope . Iceland spar is a scientific necessity , for without it research precision and technology would be hampered considerably . The earliest students of mineralogy were familiar with calcite , but the transparent variety was not discovered until early in the seventeenth century , when crystals of it were found in the bed of a stream in Iceland . It received little attention until 1669 , when Erasmus Bartholinus first recognized its powers of double refraction . The results of his investigation were published in a book , " Experimenta Crystalli Islandici , " which appeared in 1670. The law governing the action of the rerracted rays was discovered by Christian Huygens eight years later . The polarization of light rays in passing through Iceland spar was discovered in 1809 by Etienne Louis Malus , a French physicist , who published a paper describing the phenomenon . His work was closely followed by that of William Nicol , who in 1828 designed the Nicol prism which is still used as the source of polarized light in most optical instruments .

Jul 1, 1931

By S McEachern, J Lowe

An important issue currently facing the mining industry in Australia is the management and cost to the industry and other stakeholders of entry into and exit from towns and their communities. These costs can be environmental, social, economic, political or reputational. The ability of companies to engage the trust of stakeholders, including: communities, governments and investors, is critical, and corporate reputation plays a significant role in this. For the industry to secure a long-term and sustainable future, it must have the technical, business and reputation assets to proceed in a cost-effective, environmentally acceptable and socially supportive way. This research assesses reputation as a critical competitive issue for mining companies, as technology and information make mining more predictable; the physical and human assets of mining companies are less likely to be the critical resource in a Resource Based View model of competitive advantage. The proposition is that in mining today, reputation as it facilitates day-to-day operations, regulatory zeal and access to new mine sites will become the rare, inimitable and valuable resource for mining companies. This paper reports on an ongoing research program to evaluate the impact a mining companyÆs reputation(s), with its various stakeholder groups, has on a companyÆs ability to sustain competitive advantage. Integral to this study is to develop an understanding of the relationships between mining companies and their stakeholders, and the importance of corporate citizenship polices to reputation and hence to corporate sustainability. Through the identification of the drivers of reputation for the various stakeholder groups, a model of reputation formation will be developed and also reputation measures for the mining industry in Australia. The preliminary findings of this research, the results of an industry focus group conducted with representatives from regional mining operations, are reported. The industry focus group was designed to enable a better understanding of who are the main stakeholder groups and how they regard mining companies and to inform the second stage of the research project a Delphi Study of the drivers of reputation by stakeholder groups. The aim of this research is to further the understanding of the relationship between corporate citizenship, reputation and performance in the mining industry, thus assisting companies to strategically manage their corporate citizenship investments.

Jan 1, 2006

By Ali Naeimipour

Availability of accurate geological information about the rock mass surrounding a tunnel or mine working is the key to enhance and optimize the required ground support measures. Various approaches have been used to obtain data on ground conditions, including the possibility of characterizing the ground while drilling for roof bolts, by the Measurement While Drilling (MWD) system, via optical, sonic and acoustic televiewers, and using various types of gamma probes. While there are many different systems for characterizing the ground in longer, larger-diameter holes drilled downward, the options for using probes and logging systems in short, small-diameter holes drilled in horizontal or an upward direction are very limited. This paper will present the results of recent field tests using optical televiewer (OPTV) to analyze the joints and voids in boreholes drilled in different directions. The studies show that OPTV is a promising tool; however, getting a good quality image from the upward drill holes still need to be studied. Meanwhile, estimated in-situ strength of the intact rock is needed to complement the jointing pattern for rock mass classification. For this purpose, preliminary steps for the development of a borehole scratcher to estimate rock strength will be discussed in this paper.

Jan 1, 2014