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The paper first outlines the conceptual basis for evaluating and controlling geological risk. Geological risk, the economic reflection of the uncertainties associated with tonnage, grade, and other pertinent deposit parameters, is evaluated in terms of economic risk criteria. Delineation provides the deposit information required to appraise and control this risk. The improved reliability of geological estimates resulting from additional delineation reduces the economic risk associated with mine development and production decisions. However, the benefits of delineation, subject to diminishing returns, have to be weighed up against the direct and time costs involved. These costs decrease base case economic values and shift the probability distributions of possible outcomes towards, lower values. The optimum amount of delineation normally is achieved short of the point where economic risk is minimised, depending on the mining company's relative preference for a higher base case value or a lower economic risk. Then, two open pit copper mine examples, based on actual situations, are analysed to illustrate the application of the concepts presented. The first case concerns the extension of ore reserves at an operating mine. Finally, a new mine development opportunity is considered.

Jan 1, 1994

By Stewart R. D, Lawrence W, Youl M. J

The trend towards contracting by major coal mining companies such as BHP Coal and MIM Ltd is examined. Reasons why this trend is occurring are discussed and the concept of partnering is examined. Two case studies are given: the Mt Owen Mine in the Hunter Valley, NSW and the South Walker Creek Mine in the Bowen Basin, Queensland.

Jan 1, 1997

By A Woodley, N C. Kunz

A mine site water balance is important for communicating information to interested stakeholders, for reporting on water performance and for anticipating and mitigating water-related risks through water use/demand forecasting. Gaining accuracy over the water balance is therefore crucial for sites to achieve best practice water management and to maintain their social license to operate. For sites that are located in high rainfall environments the water received to storage dams through run-off can represent a large proportion of the overall inputs to site; inaccuracies in these flows can therefore lead to inaccuracies in the overall site water balance.Hydrological models that estimate run-off flows are often incorporated into simulation models used for water use/demand forecasting. The Australian Water Balance Model (AWBM) is one example that has been widely applied in the Australian context. However, the calibration of AWBM in a mining context can be challenging. Through a detailed case study, we outline an approach that was used to calibrate and validate AWBM at a mine site. Commencing with a data set of monitored dam levels, a mass balance approach was used to generate an observed run-off sequence. By incorporating a portion of this observed data set into the calibration routine, we achieved a closer fit between the observed versus simulated data set compared with the base case. We conclude by highlighting opportunities for future research to improve the calibration fit through improving the quality of the input data set. This will ultimately lead to better models for run-off prediction and thereby improve the accuracy of mine site water balances.CITATION:Kunz, N C and Woodley, A, 2013. Improving the accuracy of mine site water balances through improved estimation of run-off volumes, in Proceedings Water in Mining 2013 , pp 267-272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By S-C Shim, H-R Lee, Y Kang, H Shin

Since iron oxide and silicon oxide are major gangue components in various types of ore, FeO-SiO2 base slag, ie fayalite slag, has been often encountered in pyrometallurgical processes of non-ferrous metals. During most matte production processes such as the smelting of Cu, Pb, and Ni, the FeOSiO2 based slag is inevitably formed and plays an important role in refining crude metal as well as engineering aspects. Recently, similar pyrometallurgical approaches have been attempted in the recovery of valuable metals (Ni, Co, Cr) from wasted secondary batteries. Thus, the viscosity of the FeO-SiO2 based slag has great significance in properly controlling smelting processes. However, when molten metal or matte does not coexist with the slag during the measurement, there has been a serious difficulty in maintaining Fe valance and consequently, the slag composition. In the present research, the viscosity of molten FeO-SiO2 slag was measured in 1573~1673 K using a rotational viscometer. In order to keep the state of iron oxides, the oxygen partial pressure was controlled using CO/CO2 gas mixture. The optimised ratio of CO/CO2 could be calculated using Fe/Fe2+ and Fe2+/Fe3+ equilibria at each temperature. The composition of the slag, particularly Fe valance, after the measurement was analysed with the aid of an inductively coupled plasma – optical emission spectroscopy (ICP-OES) and an automatic potentiometric titrator. The measurement showed that the FeO-SiO2 slag has considerably low viscosity values in the molten state, and it sharply increases as the temperature decreases. In spite of the careful oxygen partial pressure control, a part of Fe2+ was found to be oxidised to Fe3+, with a maximal case reaching about 20 per cent. The increase in viscosity of FeO-SiO2 at low temperatures can be attributed to the composition change due to an unavoidable Fe2+ oxidation. In addition, the relationship between the change in the viscosity and the liquidus temperature of FeO-SiO2 based slag was discussed to understand the composition dependence of viscosity.

Jun 19, 2024

By D Q. Zhu

In this paper, the pretreatment of concentrates by roller press was present to improve the granulation of blends comprising some 30 per cent iron ore concentrates and enhance the sintering performance. It is shown that by pretreatment of fine concentrates through roller press, the content of +3 mm fractions of granulation mixture and sinter mixture permeability are elevated by ten per cent and 35 per cent. In the meantime, a sinter productivity increase from 1.51 - 1.62 t.m-2.h-1 is attainted in pot tests with similar sinter tumble index and at lower coke rate. The mechanism of the pretreatment of concentrates process to improve sintering performance of fine iron ore concentrates was demonstrated by mineralogy that better permeability help form more calcium ferrite and good microstructure of sinter, further proven by the better metallurgical performance of sinter.

Jul 11, 2011

By G DeschOnes, M Fulton

The Eleonore property (James Bay district of Northern QuTbec), owned by Goldcorp, hosts gold within stockworks of quartz-tourmaline-arsenopyrite veins and veinlets contained within microcline (potassic alteration) and brown tourmaline replacement zones. The preliminary investigation to recover gold from drill core samples showed that flotation followed by ultra-fine grinding and cyanidation is the preferred option. Ultra-fine grinding is used to liberate gold finely disseminated in sulfides. The flotation concentrate used in the investigation had a P80 of 11 ¦ and contained 75.5 g/t Au, 5.0 g/t Ag, 10.3 per cent S, 0.07 per cent Cu and traces of antimony (0.03 per cent). The mineralogical characterisation showed the presence of 65 per cent gangue minerals, 23 per cent pyrrhotite (hexagonal), 9.6 per cent arsenopyrite, 2.2 per cent pyrite and 0.08 per cent chalcopyrite with trace amounts of galena (0.05 per cent) and sphalerite (0.03 per cent). Gold was in the form of native gold and electrum. A straight cyanidation conducted at pH 11.0, DO of 3 - 5 ppm, 2000 ppm NaCN, 20¦C and for 72 hours extracted 97.0 per cent Au and consumed 31.5 kg/t NaCN. The equilibrium was reached within 24 hours. Increasing the dissolved oxygen to 16 ppm reduced the consumption of cyanide to 22.0 kg/t with 96.7 per cent Au extraction. A 16-hour pretreatment with 2.0 kg/t lead nitrate, followed by a 24-hour cyanidation reduced the cyanide consumption to 6.0 kg/t with a gold extraction of 97.5 per cent. Increasing the lead nitrate addition to 6.0 kg/t reduced the cyanide consumption to 1.2 kg/t by passivating the surface of pyrrhotite. The gold extraction remained at 97.0 per cent. It was possible to decrease the concentration of cyanide to 800 ppm NaCN without compromising gold extraction. The associated cyanide consumption was 1.2 kg/t NaCN. The passivation of gold grains was an issue when the cyanide concentration was decreased to 550 ppm NaCN. The gold extraction decreased to 92.2 per cent. The average lime addition for all the tests was 7.4 kg/t and the average silver extraction was 80 per cent. Efficient cyanidation of an ultra-fine sulfide concentrate with only 800 ppm NaCN represents an advance in leaching of ultra-fine sulfide concentrates. The high addition of lead nitrate would certainly make cyanide destruction easier; consequently reducing the effluent treatment costs and making possible to meet the discharge regulations criteria.CITATION:DeschOnes, G and Fulton, M, 2013. Design of a leaching strategy to extract gold from Eleonore Mine ultra-fine sulfide concentrate, in Proceedings World Gold 2013 , pp 71-78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By D Anderson, W Timms

"A geotechnical centrifuge can characterise and model the interaction of tailings and fluids over very long time periods by accelerating drainage and consolidation processes. This technology can be considered an environmental ‘time machine’ for designing and evaluating tailings storage projects and verifying numerical models. The Broadbent G-18 geotechnical centrifuge (2 m diameter, up to 875 rev/min) and associated equipment is a unique facility commissioned in 2011 at UNSW Australia for applied research in low-permeability materials such as mine tailings. Two centrifuge modules are available: the permeameter module for characterisation and physical modelling and the strongbox module for physical modelling.This paper presents examples of geotechnical centrifuge applications for the: consolidation of slurries and dewatering design of earthen barriers compatible with tailings chemistry prediction of contaminant mobility. The specifications and capability of the UNSW Australia geotechnical centrifuge and associated instrumentation is also presented, along with preliminary analysis of the confidence intervals associated with permeability testing of a set of samples of varying heterogeneity. Drainage velocity through a mine tailings sample increases linearly with g-level in the centrifuge permeameter until tailings consolidation occurs. Alternatively, geotechnical centrifuge experiments can be designed to limit consolidation so as to quantify permeability changes that may occur with geochemical interactions between fluids and mine tailings or earthen containments. Reactive solute transport through mine tailings can be simulated at realistic solid:liquid ratios when chemical equilibrium is maintained during geotechnical centrifuge testing. Carefully designed physical models of tailings disposal tested at accelerated gravity can therefore provide a realistic evaluation of tailings consolidation and drainage and the potential for subsurface migration of contaminants from mine tailings over long time periods.CITATION:Timms, W and Anderson, D, 2015. Geotechnical centrifuge technology for characterising the interaction of tailings and pore water over decadal time periods, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 247–252 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 27, 2015

Safe, efficient production is a common objective for all large open pit mines. Despite comprehensive policies, procedures and regulations aimed at protecting workers, several people die each year in mining equipment-related collisions. The limited sightlines of heavy equipment operators coupled with difficult operating conditions are major contributing factors to the majority of mining equipment collisions. Off road haul trucks are the most common type of machinery involved in surface accidents. These vehicles represent the primary target for improving safety performance by mine operators. Although several commercial products have been introduced to address these issues, none have achieved significant market acceptance. The current collision avoidance solutions lack integration with onboard fleet management and equipment health systems. To achieve acceptance in industry, any collision avoidance system must offer high reliability, minimal false alarms, and value for money. With these criteria in mind, this paper will examine the pros and cons of the various technological approaches to collision avoidance in an open pit mining environment. The unique global positioning systems (GPS) and camera-based proximity detection solution on offer from Modular Mining Systems will be described. This solution uses intelligent filters to minimise false alarms. Tight integration with fleet management provides context information to enhance warnings and enable back-office near-miss analysis. Available today, this combination creates a practical solution to improve the situational awareness of heavy equipment operators, at a compelling price point. Future directions for maximising heavy equipment operator situational awareness will also be examined.

May 1, 2010

By J Wall

The use of electronic detonators in civil tunnelling applications, to reduce vibration in small firings has been successfully utilised for a number of years. As part of the mining industry’s commitment to reducing blast damage during the development cycle in underground mining applications, a series of development blasts using e-Dev™ electronic detonators in a typical mining application was conducted at Resolute’s Mt Wright operations in North Queensland in 2010. Results were based on direct comparisons to the current industry standard of non-electric firings as a baseline, with as many parameters as possible being captured during the trial. Development costs are typically high in most underground mines, especially in capital development headings, which are in waste and therefore of no direct economic value, so by being able to accurately fire to design, costs relating to both ground support requirements and volume of material removed, (and therefore haulage required) can be minimised. A direct comparison of overbreak (ground blasted outside of design) and cast (distance rock thrown from blast) was also made during the trial, as well as close monitoring of the drilling accuracy.

Mar 21, 2011

By J Hadjigeorgiou

Narrow vein mining, as most types of mining, faces important geotechnical challenges. The specificity of geotechnical challenges in narrow vein mines stems from the nature of the deposits, which are often inclined, discordant and found within fractured rock or faults or in shear zones within country rock. This complicates the construction of representative geomechanical models and limits the applicability of several engineering design tools. Furthermore, in certain cases, the severity of encountered geotechnical problems is considerably greater in narrow vein than in wider orebodies. This paper provides an overview of geotechnical and other challenges in narrow vein mines with a focus on how these are currently addressed. Of particular concern is the use of manual labour working close to the mining face where there is greater exposure to geomechanical hazards. This review concludes with a particular emphasis on understanding the limitations of commonly used engineering tools and techniques to address geotechnical problems in narrow vein mines.CITATION:Hadjigeorgiou, J, 2012. Geotechnical challenges in narrow vein mining, in Proceedings Narrow Vein Mining 2012 , pp 15-22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By E N. Sparg, O D. A Deuchar, F Needham

Decline shafts are an attractive option to both new and existing mining operations where there is a need to access an inclined orebody deposit via on-reef development so as to generate a return in the shortest possible time. There are many different technologies that are available to transport men, material and rock in incline shafts. This paper focuses on the applicability of two hoisting technologies for decline shafts, namely endless and direct rope systems. The pros and cons of each system are reviewed. A common concern with direct rope haulage systems is the possibility of generating slack rope during deceleration. This paper illustrates the issues involved in designing a system so as to avoid the possibility of slack rope. In conclusion, the key factors relevant to the selection of endless or direct rope haulages for a particular decline application are reviewed. The paper is a joint submission by FFE Minerals-Vecor and Qualter Hall UK.

Jan 1, 2005

By C Tapia Cortez, A G. Dempster, R Fradet, S Saydam, T de Roche, R Shishko, J Coulton

Human ventures into space are entering a new phase in which missions formerly driven by government agencies are now being replaced by those led by commercial enterprises – in launch, satellite deployment, resupply of the International Space Station and space tourism. In the not-too-distant future, commercial opportunities will also include the mining of asteroids, comets, the Moon and Mars. This research examines the role of off-Earth mining in a growing space economy. In this investigation, the term ‘mining’ is taken to embrace minerals, ice/water and other in situ resources. As the off-Earth mining initiative could be the engine that drives the space economy, it would be useful to understand what off-Earth mining market conditions and technology requirements are needed for that economy to prosper. These specific elements are studied in the wider context of creating an economy that could ultimately support a sustainable Mars colony. The methodology for developing the model focuses on the extraction of ice from the surface of Mars to produce propellant and water for life support for a possible colony.CITATION:Saydam, S, Shishko, R, Tapia Cortez, C, de Roche, T, Fradet, R, Coulton, J and Dempster, A G, 2015. An integrated economics model for in situ resource utilisation in support of a Mars colony, in Proceedings Third International Future Mining Conference, pp 305–312 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By C Woodfull, S Munroe

Geological uncertainty is reduced by improved understanding of the relationship between regional-scale geological basement features (structure, composition, depth) and known local structural risk (such as recognised structural hazards at the mine). Coal mining and exploration entities can be more efficient and effective in managing geological risk at a range of scales. A more efficient and effective performance in forward interpreting and managing geological risk will result in a more efficient and effective exploration and also incremental or even significant mining cost improvements. In order to improve the understanding of basement features, a new 4D regional structural/basin framework for the Sydney Basin and the eastern part of the Gunnedah Basin has been constructed to provide primarily coal exploration and mining with a more integrated geological framework for ongoing subregional to mine-scale geological risk based studies. The model has been developed from a range of available regional geophysical and geological datasets, of variable detail and reliability, which have been brought together to generate a more robust structural and tectonic model than could be generated with any one single dataset. An initial regional structural model for the Sydney Basin was constructed in 2003 and an update to the model was released in 2005 (SRK Consulting, 2003; 2005). The development and ongoing refinement of the model was undertaken with financial and data support from a number of coal mining industry, gas exploration and government organisations. Prior to, and following the development of the regional structural/basin model and associated Information Base, a number of more area-specific studies have been completed, using the æbasement upÆ assessment approach. The methodology for developing comprehensive structural models, from the basement up, is outlined. The approach can be applied at a country-wide, regional or lease area scale. Case examples of where this approach has been used as an effective and efficient method in improving geological certainty and as a predictive tool to help manage geological risk are also presented.

Jan 1, 2006

By J E. Powalisz

"The application of automated sampling techniques can help to provide a representative sample of process fluids and slurries that provide data for controlling process, custody transfer and quality assurance and quality control purposes.The automation of sampling provides a more consistent and reliable sampling process and eliminates many of the human-induced errors. Automated sampling can also provide a higher degree of safety in the plant/processing environment as well as better bottom-line results.Automated, fixed volume samplers can provide a very representative sample by integrating many small ‘grabs’ of sample from a process. Automated samplers can be controlled in a variety of ways to optimise the sampling process, including:cycle ratedwell timetotal volume.Properly selected and applied, an automated sampler can effectively isolate the operator from the process fluid during sampling and, to a great degree, during sample container collection.A variety of materials of construction, including seals, are available to handle demanding mining applications. Alloy 625, alloy 2205, AL6XN® and even certain plastics are used successfully in mining slurry applications.This paper explores the application of automated, fixed volume, batch style samplers in copper/nickel and gold processing, specifically pregnant leach solution and extraction fluids.Several specific field applications are discussed, including process installation details, hardware and operation.CITATION:Powalisz, J E, 2014. The application of automated samplers in copper/nickel processing, in Proceedings Sampling 2014, pp 35–42 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 29, 2014

By M F. Gazley

The amphibolite-facies metabasaltic rocks of the Mine Mafic Package at Plutonic Gold Mine, Marymia Inlier, Western Australia, contain an estimated total endowment of 12.2 Moz of Au, which includes 4.71 Moz of past production and 2.77 Moz of reserves and resources; the remainder comprises lower-grade inventory. Over 65?000 multi-element analyses of whole-rock core and face channel samples from the underground workings of the deposit have been collected by portable X-ray fluorescence (pXRF) using a handheld Innov-X Omega pXRF unit. The analyses were performed on pulverised samples through paper bags, and were corrected using a pulverised, matrix-matched, reference standard. This method of data correction compares favourably with conventional XRF analyses performed on the same samples.A preliminary study based on pXRF analyses from a small number of drill holes found that a geochemical stratigraphy was evident in the pXRF data, and that this stratigraphy strongly controlled the location of Au mineralisation. The present study incorporates a much larger pXRF data set that samples a greater volume of diamond drill core and face channel samples and presents the data in a three-dimensional (3D) framework.This data set allows an investigation of the mineralogy of Au mineralisation with varying geochemical associations across the deposit. Historically, there has been a strong relationship identified between As and Au, which has caused issues with metallurgical performance, rendering some areas of the deposit only marginally economic. Utilising seamless data integration of the pXRF data set allows for recognition of the different styles of Au mineralisation using elemental concentrations and ratios from the multi-element analyses (Au:As, Au:As:Cu, As:Cu vs. K:V), and to visualise the distribution of these different mineralogical associations in 3D. The results of the 3D modelling and geochemical characterisation of the different styles of Au mineralisation are currently the focus of an extensive metallurgical testing program, the preliminary results of which are presented here.

Aug 22, 2011

By P Cooper

Continuous improvement using six sigma methodologies commonly follows the DMAIC methodology of define, measure, analyse, improve and control. A key requirement in the use of this approach is to ensure that data is trusted, validated and contextual. In today’s production environments it is common to find disparate technology comprising the system architecture and highly customised interfaces between the various technology layers. This complexity often leads to inaccurate data presented at the operations management layer or worse, data that is not trusted. Identifying defects and making corrective actions cannot be efficiently carried out unless trusteddata can be easily obtained with a production context. It is also common to find that disparate systems of this nature present information in multiple ways and through multiple presentation systems. This paper discusses how the use of web-based technologies in an integrated technology stack can aid the accessibility, accuracy and trust of data used in decision-making and also how a unified visualisation environment can lead to greater operator efficiency.

Jul 11, 2011

By K Edwards, A J. J Mouton

Hematite represents the vast majority of iron ore exported from Australia as the development and processing cost of magnetite is generally seen as a barrier to the development of vast magnetite resources. However, a number of magnetite projects have attracted a significant amount of interest and investment from large Chinese steelmakers.This paper compares the relative merits of the development of Australian magnetite and hematite ore from the point of view of the steelmaker, taking into account the factors that influence the capital costs of the development of the ore types and the relative costs of operating the process plants to treat these ores. By modelling the relative operating cost for the production of hot rolled coil in China for the two ore categories, the paper demonstrates the economic drivers behind the Chinese steelmakers’ large investments in the magnetite resources of Western Australia. It does this by estimating the potential value of magnetite concentrate to the steelmaker in the event that the maximum potential is realised by operating the blast furnace with a 100 per cent pellet burden.Under the conditions described, it was found that direct reduction (DR)-grade magnetite concentrate could command a price premium over 62 per cent Fe fines of up to 46 per cent (December 2014 on a cost and freight (CFR) basis). The corresponding premium for blast furnace (BF)-grade magnetite concentrate is 17 per cent, which demonstrates the dependency on grade.The capital expenses for a 14 Mt/a concentrate plant is estimated at US$3.1 B for BF-grade magnetite and US$3.35 B for DR-grade, with operating expenses at US$45 and US$50 respectively. The corresponding free on board price for a break-even net present value is calculated at US$82/t for BF-grade magnetite and US$90/t for DR-grade. The minimum long-term iron ore price (62 per cent Fe) that would be required to underpin such a project is estimated at US$78/t CFR for BF-grade magnetite and US$68/t CFR for DR-grade concentrate.Apart from the financial benefits, it is demonstrated that the use of magnetite concentrate in ironmaking has the potential to reduce CO2 emissions by approximately 400 kg per tonne of hot rolled coil.CITATION:Mouton, A J J and Edwards, K, 2015. Magnetite – a higher-grade blast furnace feed and its potential benefits for the ironmaker, in Proceedings Iron Ore 2015, pp 613–620 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Robertson K. S, Hunter T. C

AEG-Elotherm's electromagnetic dosing channel, or Eldomet, is a recent invention enabling the transport and metering of molten metals. The development of a reliable refract- ory lining, and the use of suitable construct- ion and operating techniques has led to the successful application of the Eldomet for casting copper anodes at Copper Refineries Pty. Ltd.

Jan 1, 1974

By G V. R Goodman, G J. Chekan, J M. Listak

The extraction and transport of coal from underground coal mines can result in significant liberation of coal and/or silica dust into the mine atmosphere. Mine operators have long used ventilating air as a primary means of diluting generated dust, removing dust from the working faces and preventing dust from reaching the minersÆ working environment. As production levels have increased, mine operators continue to be challenged in maintaining dust concentrations below compliance levels. The need for maximising the effectiveness of available ventilating air in conjunction with other effective controls, such as water sprays and dust collectors, continues to be critical to the long-term health of mine workers. The National Institute for Occupational Safety and Health (NIOSH) has conducted full-scale laboratory and mine-site research to evaluate improved application of dust controls for both longwall and continuous mining methods. A summary of recent research results and recommended practices will be provided.

Jan 1, 2005

By A Suwandhi, H Utama

PT. Indo Muro Kencana (PT.IMK) is a gold mine that is located in Central Kalimantan, Indonesia. Drilling and blasting activity is applied in order to support mining production. Drilling and Blasting (D&B) planning is conducted by its engineers. A drilling and blasting contractor conducts drilling and blasting activity. The objective of this paper is to evaluate the implementation of the scaled depth of burial (Chiappetta and Treleven, 1997) in explosive charging sheet application to increase blast efficiency. The function of the scaled depth of burial is to maintain stemming height above explosive charge in order to prevent the ‘over energy’ condition, to reduce the excessive fly rock possibility, to maintain rock fragmentation (digger’s productivity) and to increase blast efficiency. The focus of this paper is to implement the scaled depth of burial as a reference in D&B planning and practice, especially in designing stemming height. The purpose of this paper is to validate that the scaled depth of burial can be used as an engineering tool in D&B practice in PT.IMK. However, scaled depth of burial cannot applied as an engineering tool to determine stemming height above explosive charge for trim blastholes and secondary blasting area. In general, the implementation of the scaled depth of burial in PT.IMK is applicable for production blastholes (ore and waste blasting). In conclusion, it is clear that scaled depth of burial can be used as an engineering tool to create explosive charging sheet and also to increase blast efficiency (ore and waste blasting) in PT.IMK.

Jun 22, 2022