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By B Mohanty, Y C. Lizotte

Optimization of blast fragmentation in underground hardrock mining requires analysis of its effects on loading and haulage equipment, together with the downstream materials handling system, with the objective of minimizing total mine operating costs. A methodology is reported which has been developed to quantify the actual fragmentation and equipment performance in the field. This is data which has seldom been practicable to capture nor received serious attention in mines. Based upon the experience gained in underground studies, a prototype standard is proposed which aims to summarize the pertinent data, collection and analysis for fragmentation assessment. This relates to parameters of direct measure, such as mean size and distribution, as well as muckpile and work environment. The paper concludes by defining the impact of fragmentation on the loading and downstream handling system.

Jan 1, 1991

By Khushaal Popli, Vanessa Roeland, Brian Hall, Carl Diederichs

Highland Valley Copper (HVC) has embraced an integrated Mine to Mill approach to comminution since the late 1990s. Previous blasting optimization was carried out through adjustments to blast pattern geometry (i.e., reduction of burden and spacing). This approach proved very effective and HVC reduced the burden and spacing of high energy ore blast patterns to what was considered the practical limit that still allowed for efficient drilling and bulk truck loading operations. While mining in the bottom of the Valley pit near the end of the previous pushback, HVC encountered high static groundwater conditions which enabled the transmission of elevated inter-blasthole pressures that had the potential to exceed safe operating limits for initiation products. This risk was mitigated through an expansion of burden and spacing for the high energy ore patterns, reducing the application of blasting energy and increasing the average particle size in Mill feed.

Feb 6, 2023

By C. McAllister, D. Preece, J. Berendzen

"The Multiple Blasthole Fragmentation (MBF) model models multiple explosive charge contributions and the effect on fragmentation of delay timing with its associated scatter for each blasthole. The model uses near-field blast vibration attenuation parameters and the ground p-wave velocity as inputs for part of the in situ rock property to model rock fragmentation. It models most blast design parameters explicitly and simulates the effect of wave reinforcement due to the interaction of simultaneously arriving waves or diminishing cooperative contribution from long delay intervals between charges within a blasthole or among blastholes. The fragmentation size is calculated at three-dimensional grid points within a blast, and the fines and oversized blocks are treated explicitly. The model takes a surveyed irregular geometry of the free face of a blast as the calculation boundary.This paper presents a case study on applying the MBF model at an openpit mine. Near-field vibration measurements from signature hole blasts were conducted to obtain the stress-wave magnitude and attenuation parameters as well as ground sonic velocity. A production blast was then monitored with the corresponding fragmentation measured, serving as site-specific inputs to the MBF model. Various blast design scenarios were then simulated to develop ones that provide better fragmentation to improve mill throughput for the mine. IntroductionThe semiempirical fragmentation models currently found in the literature (Cunningham, 1987; Lownds, 1995) cannot explicitly model contributions from multiple blastholes with varying delay intervals. Most of these models are not three-dimensional. Furthermore, these models predict an average fragmentation size within a volume surrounding a blasthole and use the average size to generate a size distribution over the volume. The percentage of fines and oversize blocks is included in the distribution. Typically, such models are inadequate for predicting fines and oversize blocks (Cunningham, 1987)."

Oct 1, 2016

By V M. Silva, P A. A Martins, V O. Matthew, A L. S Fonseca, E B. Cunha, A J. D Ferrari, E M. S Silva, A C. Silva, D R. T Vilela

The Anglo American phosphate mine is located in the Brazilian state of Goiás and possesses one of Brazil’s most important phosphate rock deposits, with the site being the country’s second largest producer of phosphate rock concentrate. Despite the site having been in operation since 1979, the mining team only started using explosives in 2004 when rocks with greater hardness started to appear in the mine’s geological profile. Rock excavation was previously performed mechanically. Until 2013, only rocks with high hardness were blasted, this following the standard drilling grid that was defined in 2004 without any changes in the blast parameters. The aim of this paper is to show how fragmentation optimisation has yielded positive results at all stages of the production chain, from the mine to the mill passing through an impact hammer crusher, a rod mill and ball mill, operating in close circuit with hydrocyclones.While incorporating the mine to mill holistic approach during the operational integration, the focus was on defining the blasting domains and respective optimal fragmentation and measuring the benefits of blasting in terms of reduction in energy and grinding media consumed in the comminution processes. In the first stage, the blasting team made changes to the blasting parameters and assessed the effects of these changes on fragmentation using computer software and on-site measurements. This generated a database that made it possible to divide the mine into blasting domains. For the second stage, teams from the plant, geology, mine planning and operation departments jointly made comparisons between the performance when processing stockpiles, which only included high hardness blasted ore (20–30 per cent of blasted ore). Changing the drilling grid’s size from 3.0 m × 3.8 m to 2.0 m × 2.6 m for high hardness rock with the presence of silicates resulted in a 40 per cent reduction in the P80 for the blasted material (from 459 to 278 mm), while changing the grid from 3.0 m × 3.8 m to 2.6 m × 3.2 m for high hardness rock without the presence of silicates generated a reduction of 25 per cent (from 270 to 204 mm). There were gains observed from the measurements at the mineral processing plant in terms of specific energy spent on comminution and on the consumption of grinding bodies in the rod mill. There was a measured reduction of circulating load during secondary grinding and a reduction in slime generation.CITATION:Silva, A C, Martins, P A A, Silva, E M S, Fonseca, A L S, Ferrari, A J D, Cunha, E B, Silva, V M, Matthew, V O and Vilela, D R T, 2015. Fragmentation optimisation – adopting mine to mill for reducing costs and increasing productivity, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 363–368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Douglas Bartley

As the economy continues to slowly recover, our industry continues to finds ways to increase productivity while being forced to cut costs. The drilling and blasting process is the starting point of any aggregate or mining process. Many people refer to it as the “Primary Crusher” as it will always be more efficient to crush rock with explosives energy than it will be mechanical energy. It is the more efficient use of this energy that is addressed in this paper.

Jan 1, 2012

By J L. Lett, I Brunton, T Thornhill

Block cave fragmentation has been documented in the literature to have a significant impact on mine design, performance and downstream material handling and comminution processes. Due to this impact, emphasis is placed on the premining prediction and subsequent quantification of primary and secondary fragmentation distribution. This paper discusses the fragmentation prediction and assessment methodology employed at the Ridgeway Deeps (RWD) and Cadia East PC1 (CEPC1) cave operations.Prediction of drawpoint fragmentation was based on an iterative process, which relied on an improved quantitative and qualitative understanding of the rock mass as the mining project developed. In particular, the collection of scanline mapping data provided detailed information in relation to discontinuity trace length, persistence, termination characteristics and large-scale planarity. This allowed an improved estimation of select modelling input parameters, in particular ‘block forming’ discontinuity orientation and strength characteristics.With the start of production, drawpoint fragmentation assessment was undertaken using digital image processing (DIP) techniques for drawpoint extracted tonnes up to 61 000 t. This technique provided a consistent methodology to estimate changes in fragmentation as the block cave matured. It can generally be concluded that the measured mean fragmentation distribution became finer as drawpoint tonnage increased. The incremental change in fragmentation distribution (per 10 000 t) was not uniform, with step changes evident. In addition, for a given geotechnical domain and drawpoint tonnage, the measured fragmentation distribution range was found to vary significantly. A possible explanation for these observations may relate to the disturbed flow behaviour noted from marker experiments at RWD and CEPC1. These experiments indicate that material reporting at the drawpoints (for any given tonnage extracted) may be sourced from highly variable heights within the cave, with finer material preferentially reporting.A comparison between predicted and measured drawpoint fragmentation distribution indicated two general findingsa close match between predicted and measured distributions for material greater than 1.0 m3an under prediction of finer material passing 0.5 m3 relative to measured.The findings would indicate that the fragmentation modelling frameworks utilised at both RWD and CEPC1 were deficient at predicting the percentage of finer material for both primary and secondary fragmentation.The wide range in fragmentation distributions observed in the measured results, and the discrepancy between modelled and measured fines should be considered in the design of mine (material flow, extraction level geometry and draw rate), material handling (crushing and material movement), and downstream milling (comminution and metal recovery) processes for future block cave mines at the Cadia Valley Operations (CVO). With respect to fragmentation distribution range, a sensitivity analysis should be undertaken for these design considerations, with a range in predicted fragmentation distributions investigated (for example, lower quartile, mean and upper quartile). For future mines with similar geotechnical and mining conditions, the calibration of fines should be considered in any fragmentation distribution prediction to match those measured previously.CITATION:Brunton, I, Lett, J L and Thornhill, T, 2016. Fragmentation prediction and assessment at the Ridgeway Deeps and Cadia East cave operations, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 151–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Thomas C. Atchison

An understanding of the physical processes involved in breaking rock with explosives will lead to better blasting techniques. In this chapter known rock breakage principles will be outlined, some conjectural ideas will be discussed, and areas needing further study will be pointed out. The principles outlined will serve as a basis for the design of blasting rounds described in the following chapter. 7.2-1. Factors Important to Rock Fragmentation. The efficacy of explosives as tools for rock fragmentation lies in their ability to deliver almost instantaneously large amounts of energy to a limited portion of the rock. When an explosive charge is detonated in a drill hole, its energy is released in a very small fraction of a second in the form of gas at extremely high pressure and temperature. The mechanics of the transfer of this energy to the rock and the resulting breakage are complex and not completely understood. Factors that have been identified as important to the fragmentation process may be grouped in three categories: explosive parameters, charge loading parameters, and rock parameters. EXPLOSIVE PARAMETERS. Explosive parameters known to influence breakage are density, detonation velocity, detonation impedance, detonation pressure, gas volume, and available energy. Detonation pressure is probably the best indicator of an explosive's ability to break solid hard rock. Detonation pressure is roughly proportional to the product of density and the square of the detonation velocity. The relative ability of different explosives to transmit their pressure to stress in a given rock is function of their detonation impedances. Detonation impedance is the product of density and detonation velocity. The volume of gas released in the explosive detonation undoubtedly is of importance, at least in the later stages of breakage, and is probably

Jan 1, 1968

By Douglas Castleberry

The degree of fragmentation obtained in primary quarry blasting has always been a factor in the speed of digging' the muckpile This paper will discuss a case history of increased production and associated lowered costs from increased fragmentation. The quarry under discussion is fairly new, located in Georgia, and is in the large operation .category. Loading is done by three yard shovels, and, primary crushing by a 48" x 60" haw crusher preceded by a 5' wide feeder. The stone is a hard granite gneiss, of Los Angeles rating 22, and apparent specific gravity is 2.68. The product is shipped to points in that state for railroad ballast, concrete aggregate, and road building stone. Inasmuch as fairly large shovels and a large Jaw were to be utilized, initial drilling and blasting were pointed toward producing fairly large sized muck for this large equipment. This was following a concept somewhat in vogue for some years in the Southeast wherein many large equipment plants would tend towards larger fragmentation, and smaller equipped plants would conversely tend toward attempts at smaller sized rock piles for smaller shovels and crushers.

Jan 1, 1960

By Y Nagendra, A. Ravi Kumar

A breakwater is a construction for protecting the marine structures like port, harbor, or anchorage-basin and berthed marine vessels from the destructive influence of the sea waves. The breakwater is constructed by using geologically competent, heavy, massive rock like granite, basalt etc having physical and mechanical properties within the limits specified by the designers. The construction requires boulders in varying sizes ranging from 0.5 kg to 20,000 kg. The stones from 0.5 to 1000 kg are called as core fill and boulders greater than 1000 kg are termed as armor blocks. These armor blocks cover and protect the core fill and prevent it from escaping. The requirement of armor blocks ranges between 25 to 35 %. The rest is core fill. However, the actual requirement depends on the breakwater design. In this context, the task of the mining engineer is to economically produce armor blocks and core from the designated quarry in right proportion with minimal losses. The whole bunch of engineering ingenuities should be put forth for obtaining the required armor blocks. The armor block production from any blast depends chiefly on geological conditions, bench dimensions and blast design. This paper is an attempt to bring out the various parameters affecting the performance of the blasting for armor block production using a case study.

Jan 1, 2005

By Maxime Tacher

BRP (Bombardier Recreational Products) designs and commercializes recreational vehicles such as watercrafts, sport boats, snowmobiles, ATVs... The Spyder roadster is the last product in the Can-Am product family lineup. To remain at the forefront of innovation, a hybrid motorization version of the Spyder is being developed in order to reduce fuel consumption and emission of greenhouse gases. But, the addition of electric components (e-motor, lithium-ion battery... ) raises the issue of added weight and volume. This article deals with the mass reduction of this Spyder by optimizing its frame.

Jan 1, 2011

By M. Grozdanovic, D. Marjanovic, M. Ilic

We present a framework for solving the problem of functional compatibility between process control equipment in control centres at underground mines and operator capabilities. The equipment incorporates displays of current ventilation, gas, and fire hazard data, status of alarm and early warning systems, a voice communication subsystem, and facilities for recording and printing ofdata and reports. The layout of the existing control panel is compared with a recommended design. The basic principles of ergonomic design and arrangement of the controls and indicators, as well as ease of use, type of operations carried out with these controls, and operators’ viewing angles are discussed. The objective is to improve the usability of control panels, display boards, and graphic screens so as to enhance the functioning of control centres and optimize control of technological processes in coal mines.

Jun 10, 2024

By H. Lee

Recently, the effects of global climate changes have become top concerns for governments? decision making regarding infrastructure investments. Extreme weather events that exceed the capacity of existing systems have considerably increased in frequency, and the potential effects of changing trends in temperature and rainfall on infrastructure are difficult to ignore. It is essential for governments to estimate the costs and benefits of adaptation to climate change to properly assess the financial feasibility of infrastructure adaptation strategies. This paper proposes a framework for estimating the economic aspects of infrastructure adaptation to climate change. The framework is composed of three steps of implementation: establishment of alternatives for infrastructure adaptation, performance prediction of infrastructure using future climate scenarios, and asset valuation based on costs and benefits. The first step specifies target assets, their adaptability to climate change, and applicable adaptation technologies. The second step evaluates the effects of climate change on the performance of infrastructure. The last step determines the optimal adaptation strategies among various alternatives based on their net benefits. The framework reasonably incorporates future climate scenarios into the estimation processes for climate change effects and provides a basis for budget allocation for governmental infrastructure investments. The framework is expected to assist government decision makers in establishing adaptation strategies in a rational manner under uncertain future climate change.

Aug 1, 2013

By W. R. Paterson, W. Morton, D. B. Cameron

The Massbal II computer simulation program has been used to develop a general framework for the building of thermochemical models of metallurgical processes. The framework allows the rapid, simple construction of complex models of process equipment for use in flowsheet design, planning and plant operation. Application of the program to model the iron-making blast furnace and a flash smelting process is described

Apr 1, 1991

By D. Getzlaf

"Oilfield cementing has been utilized in the industry since the turn of the century. Originally, wells were shallow and criteria for well integrity were somewhat limited. Since that time, wells have stretched the envelope in depth, temperature, and pressure. Environmental regulations have also become more stringent, thus, the importance of hydraulic isolation between permeable zones, and between these zones and surface has become more and more important.Initially, oilfield cements were comprised predominantly of construction cement and very limited additives. As time progressed, additives were incorporated to control pumping time or placement time and little effort was placed on optimizing actual components within the cement chemistry. This paper presents issues and concerns created by adding just one new component to the fundamental chemistry of an oilfield cement."

Jan 1, 2004

By J. G. Manchuk, M. Thurston

"The degree of uncertainty associated with a natural diamond resource is important to quantify from the time of discovery through the production lifetime. Data collection occurs during the discovery, exploration, delineation, and production or recovery phases. Quantifying the relationship between data and uncertainty is an important component of project valuation. The value of data is measured as their potential to reduce uncertainty if they are collected. A method is developed using Monte Carlo simulation for predicting resource uncertainty and valuing data during critical phases of development, particularly discovery and exploration. The technique is applied to diamond pipe deposits.RÉSUMÉ Il est important de quantifier le degré d’incertitude associé à une ressource diamantifère naturelle, depuis le moment de sa découverte et durant toute la durée de l’exploitation. La collecte de données se fait durant les phases de découverte, d’exploration, de délimitation, et de production ou de récupération. La quantification de la relation entre les données et l’incertitude est une composante importante de l’évaluation du projet. La valeur des données est mesurée en tant que leur potentiel à réduire l’incertitude si elles sont recueillies. Une méthode a été développée qui utilise la simulation de Monte Carlo pour prédire l’incertitude de la ressource et évaluer les données durant les phases critiques du développement, surtout celles de la découverte et de l’exploration. La technique est appliquée à des gisements de cheminées diamantifères."

Jan 1, 2015

By Steve Davidow, Ashely E. Evans, Peter M. Kandaris

"Annually thousands of deep foundations are constructed across North America supporting high voltage transmission line structures. However, a recent state of the practice survey by the Deep Foundation Institutes’ Electric Power Systems Foundation Working Group discovered that the electric power utility industry lacks consistent foundation design guidelines. The survey identified a wide variability in design assumptions, a minimal understanding of risk based analysis, and a need to standardize design methodologies. This paper summarizes the state of practice in electric system foundation design and proposes a framework for risk-based foundation design by accounting for uncertainty from both loads and resistances. Loads derived from electric system codes do not necessarily provide a compatible level of reliability for the design of foundations, as they are a mixture of probabilistic and deterministic values. Load uncertainty is derived from variability in weather conditions, structural models and material properties, typically accounted for by code derived overload factors. Resistance uncertainty arises from variability in natural soil properties, resistance models, subsurface construction techniques, material sampling methods, and limited observations. A consistent methodology is offered relating nominal resistance capacity (strength) to structure loads and service state criteria. Discussion also includes the need for risk-based assessments to account for non-structure load influences (fluvial loads, scour ground loss, liquefaction, etc.).INTRODUCTIONNearly 40 years ago the Electric Power Research Institute (EPRI) embarked on a major research effort to optimize reliability and economics of transmission line foundation design. Strategies focused on improvements in design models, site characterization, exploration strategies and testing to reduce uncertainty and variance in analysis. Transmission line engineers realized that safety and reliability advancements in design based on probabilistic approaches, with a focus on the unique nature of transmission line, could better control risk and cost.Some transmission line professionals took full advantage of these advancements, particularly where research led to improved software and models. Yet, even after two decades of extensive research, by 1995 the industry still had made little progress in changing design habits. The majority of designers were still characterizing sites via deterministic methods, using loads that may or may not relate to a consistent probability of occurrence, and applying a traditional global factor of safety approach (Phoon, et al. 1995). The following two decades have seen even greater developments in software and reliability-based analysis methods, but old habits seem to die hard as recent surveys show less than half of design professional quantitatively assess risk in their design process."

Jan 1, 2017

By M. A. Oskouei

Draglines are the main energy consumers in strip mines. Given the growing cost of energy and environmental concerns, it is important to properly understand dragline energy efficiency. The goal of current research at Missouri University of Science & Technology is to account for operator practice and operating conditions in modeling dragline energy efficiency. This paper presents preliminary correlation analysis and a framework for stochastic modeling of dragline energy efficiency. Thirteen operating parameters (including cycle times, payload, swing angle, and height of dump pile), operator working schedules, operating conditions, and drag, hoist, and swing energies were monitored for an 85 yd3 dragline. Operator effects were examined by two-sample t-tests. The relation between the parameters and energy consumption were assessed by correlation analysis and a stochastic modeling framework has been proposed for dragline energy efficiency. The results show that operator effects are significant (p< 0.05) and energy efficiency is correlated with operating parameters. The completed model will help the coal mines better predict energy consumption, with uncertainty, for different operating conditions.

Feb 27, 2013

Access to secure and reliable water resources is fundamental to the minerals industry. In recognition of that requirement, and cognisant of extensive contemporary public water debate and reform initiatives in Australia, the Minerals Council of Australia (MCA) approached the Ministerial Council on Mineral and Petroleum Resources (MCMPR) proposing the establishment of a Joint Working Group to prepare a framework of strategic principles to ensure responsible water management at a site and corporate level, manage risks and identify opportunities. The Framework provides high-level guidance on issues that should be addressed in water decision making across Australia in relation to mining and associated processing operations. It identifies principles and objectives for adoption in four areas, viz: valuing water, strategic water planning, implementation, and engaging stakeholders. Given the high level nature of the Framework, and its national application, it does not seek to replicate detailed guidelines already widely available in each state and territory on operational water management practices and associated regulatory issues at mine sites. The Framework includes a series of case studies from across Australia that demonstrate where strategic thinking, wise water management and close consultation with stakeholders has delivered better water use, more profitable operations and excellent community/stakeholder relationships. The Framework was formally launched on behalf of MCMPR by the Western Australian Minister for Resources at the MCAÆs Sustainable Development Conference in Perth in October 2006. No full paper available for this extended abstract

Jan 1, 2006

By AIME AIME

SHORTLY after graduation from Girard College, Francis B. Foley found employment in the open-hearth department of The Midvale Steel Co. later joining its research department. After twelve years with Midvale he became a professor in the department of metallography of the University of Minnesota. With the coming of the World War, he was called upon by the War Materials Investigation Committee to work on the manganese problem. In 1918, he took charge of the iron and steel division of the U. S. Bureau of Mines, at Pittsburgh, and. after a year of co-operative study of carbon steels with the late Henry M. Howe, was assigned to the Bureau&apos;s stations at Minne-

Jan 1, 1937

In order to assist in the building up of the industries and commerce of France, by cooperating with the Congres General du Genie Civil, the four Founder Societies have appointed the following committee: E. G. Spilsbury and Arthur S. Dwight representing the American In-stitute of Mining and. Metallurgical Engineers; George F. Swain and Nelson P. Lewis to represent the American Society of Civil Engineers; Charles T. Main and George W. Fuller to represent the American Society of Mechanical Engineers; Lewis B. Stillwell and Andrew M. Hunt to represent the American. Institute of Electrical Engineers.

Jan 12, 1919