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By M. D. Bath

Minproc Engineers Inc. (Minproc) recently completed the construction and start-up of a process facility to treat 14,000 t/d of gold-silver ore at Kori Kollo, Bolivia. The comminution circuit consists of crushing and SAG-ball mill grinding. Breakage characteristics of the ore were determined and a circuit model developed. This enabled variations of the circuit to be simulated, and evaluated in terms of predicted performance to provide the criteria for final engineering design. Subsequently, analysis of the operating circuit provided data for circuit model-fitting. The validity of the original model and circuit performance predictions are discussed.

Jan 1, 1994

By J. A. Wallace

U. S. Steel's coal mining research activities are directed toward providing new or improved hardware and techniques to increase productivity or reduce cost. Because more than 80 percent of U. S. Steel's coal production is obtained from continuous miner sections, most of our research efforts are focused upon that mining system. Current and historical time study data show that our continuous miners only operate about 30 percent of the available face time. This limited equipment utilization is the result of the delays or interferences imposed by the non-coal-cutting phases of the continuous mining cycle. The most time consuming of these delays are: waiting-on-roof-support, tramming between alternate work locations, waiting-on-haulage-capacity, and in some mines waiting for excessive methane concentrations to clear. Because waiting on roof support is our most time consuming delay, several programs are underway simultaneously to address this problem. In one of these we are developing a patented microprocessor-based control method and apparatus to improve roof drilling performance. This increase is attained by using the microprocessor to adjust electrohydraulic valves which control drill thrust and rotation speed. The microprocessor is designed to continuously search for an optimum combination of thrust and drill rpm to maximize penetration rate at all times.

Jan 1, 1979

By J. Armitage, J. Erskine

Feed level and thickness measurements are essential in the optimization of an electric arc furnace. A precise measurement of the feed thickness and level gives operators the ability to increase the smelter efficiency and reduce the maintenance cost. Hatch has developed a radar system which is an affordable, low maintenance, and accurate level measurement system. The radar units can be installed across the furnace to measure the feed level and the feed thickness can be calculated with one slag level sounding. The present paper describes the development of radar systems as a process optimizing tool by furnace controls. The authors will discuss the challenges involved in installing eight radar units on the roof of a six-in-line electric furnace.

Jan 1, 2015

By V A. Maltsev, V I. Panin

The question of prediction and prevention of dynamic events û rock bursts (RB), tectonic rock burst (TRB) and mining-induced earthquakes (MIE), induced by large-scale mining, are discussed. The mine itself and the host geological environment are taken as a natural-technical system (NTS) whose evolution is characterised by alteration of the adaptation-bifurcation (catastrophes) periods. So, to predict TRB-MIE means to predict the limiting NTS states that are determined from the NTS geological monitoring data, and to prevent the said events means to control the processes of rock deformation and failure within the critical zone. The study considers particular examples of how TRB-MIE-events are predicted and prevented in apatite mines, Kola peninsula, Russia.

Jan 1, 2000

By Ravi Sahu, Kris Jeremiah

This paper aims to study the benefits of using Post Processed Kinematics(PPK) surveying methodology combined with Drone photogrammetry to achieve highly precise positioning (X, Y, Z) of drill holes based on the drill pattern and to highlight innovative workflow of transmitting the drill plan to smart drills for accurate drilling.

Feb 1, 2020

By C. Morel, P. Fredes, L. Rojas

This article presents a comprehensive study on the development and application of the specific module called "Exclusion Zone" created by Orica to determine blast evacuation exclusion zones. This module, integrated into the "SHOTPlus™ (blast design software)" software, has been used in the context of optimizing equipment evacuation exclusion zones in a northern Chile mine. The main objective has been to reduce the travel times of extraction equipment without compromising the safety of individuals. The module considers various factors such as the explosive charges used, stemming, sector topography, and detonation sequence to determine the rock projection generated by the blast. Furthermore, it utilizes information collected by drones and support tools such as Groundprobe and BlastVision™. The results obtained demonstrate that the use of this technology has allowed the optimization of blast evacuation distances in the northern Chile mine, generating significant economic benefits for the client.

Jan 1, 2024

By Jochen Maurer, Dr. Christian Hoyme, Dr. Hans Regler

Currently, it is very difficult to obtain qualitative and quantitative information about the status and production process of a construction site. As a rule, companies depend on reports from on-site experts. There is no end-to-end digitalization due to the mobility of equipment and ever-changing locations. Equipment from different manufacturers, especially in special foundation engineering, is highly specialized. Any data collected by this equipment is recorded in proprietary formats and made available on the manufacturers' platforms. This exacerbates the situation, making simple analysis of performance indicators impossible. Most functions such as construction diaries, equipment utilization analyses, etc. are implemented only as standalone solutions. This does not allow for prompt visualization and intervention in critical process sequences because the construction site process is usually managed using a cost-based method. Furthermore, special foundation engineering requires a high level of expertise in an extremely wide range of construction processes. In this article, the results from a set of non-proprietary performance analysis tools are presented using numerous practical examples. Once a construction element is completed, the equipment data is immediately transferred to the platform using the latest cloud technology. Because the data is normalized, construction progress can be documented immediately, even for mixed equipment fleets. Bottlenecks can be immediately detected by visualizing the current performance of the production process, which is broken down into individual steps. Modern analyses of this equipment data improve quality, thereby providing better information about current performance. These sets of tools are essential for changing from the current monetary or cost-based method of process management to time- and bottleneck-oriented management. This makes it much easier to identify the critical path during projects. The article shows that processes can be documented and managed.

By S. Banisi, M. R. Yarahmadi, S. R. Mortazavi

Nowadays the development of automatic on-line sampling systems has enabled large amounts of data to be available to plant managers. These data are inevitably prone to random and sometimes systematic errors. Data reconciliation methods are used to deal with random errors. In these methods, the measured data are adjusted in accordance to their error, so that the mass conservation law is satisfied at the same time. Measured data may also contain systematic errors, using these data in mass balancing software will result in inaccurate or even irrational results. In this paper three methods for detecting systematic errors (global test, node constraint test and maximum power constraint test) were presented. A step by step method to locate the systematic errors was demonstrated. Then, the new version of Movazen©, a mass balancing software, was introduced and used to locate systematic errors in the measurements taken from the Sarcheshmeh pilot plant copper flotation circuit. Keywords: Mass balancing, data reconciliation, random error, systematic error

Jan 1, 2020

By Michel Rodrigo Luiz, Glaucio Augusto Polini, Leonardo de Souza Melo, Giovani Rodrigues, Giardini F. Lazzarin

ArcelorMittal's pickling and cold rolling line has been demanded to increase production since the installation of equipment in 2015. In addition to improving productivity related to these new equipment, several additional jobs were planned and executed on equipment already installed has been carried out in order to improve the efficiency of the line. The present work exposes what was done in the scale breaker (tension leveler) to improve the availability results of the section and consequently of the line.

Oct 1, 2019

By C Nyoni, T Nguyen, C R. W Seymour, G D. Dempers

Unplanned dilution directly adds cost to production from mining, milling, tailings disposal and administration. Additionally, unplanned dilution decreases the productivity, profitability and may affect the planned life of mine. Identifying and quantifying the potential for unplanned dilution allows optimisation of the mining plan and mining practices to minimise the adverse impact on productivity and the cost of production. The Dilution Rating System (DRS) has been developed to more accurately predict dilution thickness and the variable potential for dilution, from individual stopes to life of mine planning. The DRS utilises the methodology developed for the Mining Rock Mass Model (Seymour et al 2007, Jenkins et al 2009) to generate a three-dimensional dilution rating model, which is then calibrated against stoping performance. Dilution can be predicted more accurately and the parameters affecting dilution can be determined and minimised through improved mining techniques, for example blasting and ground support design. Potential high dilution areas can be identified in the planning stages of the mine and systems put in place to mitigate the risk of excessive dilution. This paper presents the methodology used to develop the DRS and then successfully predict dilution for both the hangingwall and footwall of stopes at the Gara Gold Mine. This has enabled the expected dilution to be more accurately predicted and mitigated where possible thus reducing unplanned dilution.

Mar 15, 2021

By Jr. Foot

EIMCO Process Equipment Company has introduced the new SmartCell series of conventional flotation cells. The flagship of this new development is the 5000 ft3 cell that is the largest available in industry. This new series of cells includes a cylindrical tank design, a conical draft tube and froth crowder. Optional air control, wash water addition and embedded expert control are available. A discussion of the design parameters, energy efficiency, testing, and commercial plant results are presented.

Jan 1, 1997

By P T. Stoker, A Allman, D P. Carville

Classification of mineral resource estimates is one of the most important responsibilities of the Competent Person. In recent years, classification decisions have been driven more by the detailed block-by-block attributes generated by the now widely applied geostatistical estimation methods, and less by a general geological overview. This is increasingly resulting in æspotted dogÆ outputs, in which blocks of Inferred Resources or unclassified material separate blocks of Measured and/or Indicated Resources, or individual drill holes are surrounded by annuli of Measured and Indicated Resource blocks. Not only are such outputs potentially misleading, since they ignore fundamentals such as continuity of geology and mineralisation between drill holes and the imprecise nature of resource estimation, they can also cause substantial problems for engineers undertaking mine designs and estimating ore reserves, particularly for underground mines. Competent Persons for mineral resources must keep in mind the purpose of their work, and should use their experience and judgement to avoid or smooth out æspotted dogÆ classifications, providing a result commensurate with the level of geological and resource estimation confidence. For their part, ore reserve Competent Persons must understand the resource estimation and classification process, and should question resource classifications that are not consistent with the level of geological and resource estimation confidence.

Jan 1, 2006

By D A. Sims

This paper outlines the contributing factors to a series of erroneous Mineral Resource estimates which led to considerable loss, including significant reduction of mine life and consequently a large write-down of asset value. The error prompted divestment of the mineral asset in the short-term by the owners, a major mining company. There were multiple and complex contributions to the result: • The mine was undergoing a transition in the deposit geology with increasing depth that was not accommodated in the models. Early indications of the geological transition in initial drilling were generally unrecognised in resource modelling. The shortcomings of the models became apparent with increasing infill drilling and subsequent production reconciliation. • There was a lack of recognition of, and confidence in, site-based input and skills by corporate technical management. The site had a reputation internally for over-delivery to plan early in its life and that supported the anticipation of ongoing metal delivery into the mine plan by management. • A corporate lack of confidence in site being able to adequately domain the mineralisation led to the use of a CIK domaining process, rather than one which was geologically based. This domaining process led to gross over-statement of mineralisation trends reflected in the subsequent OK estimate. • Timelines on the outsourced estimation process were so short that validation was not possible. Obvious errors in the estimate versus data were not able to be used to correct the issues and the site’s Competent Person sign-off occurred without adequate checks. This case study is presented to reinforce the concept that Mineral Resource estimates are not solely based on the ability of the Competent Person to satisfactorily guide the process. There are usually multiple complex issues in the estimation process which need to be recognised and considered in judging reconciliations of model to actual.

May 24, 2023

By Dan Brunner, Scott Thomson, Ben Lyddall, Duncan Thomson

Geosensing is used in oilfield drilling in conjunction with geophysical tools to support characterization of rock properties, geology, and reservoir conditions. This technology is now available to the mining industry and has been successfully applied to underground in-seam directional drilling in Australian coal mines for geologic exploration and methane drainage. The system utilizes a range of drill rig and wellhead mounted sensors which, combined with analytical software, produce real-time data from which 3D spatial features can be accurately modelled significantly in advance of mining. This innovation greatly expands on the information obtained from current in-seam directional drilling practices and provides for improved characterization of coal seams, including soft and weak zones, locations of geologic discontinuities, and analysis of formation flow. This paper provides a description of the geosensing system and the interpretation of actual data from long in-seam directionally drilled methane drainage boreholes at mines in Australia, and discusses how this system increases the value of directional drilling as an exploration tool for the coal mining sector, and the evaporite and hard-rock mining sectors where directional drilling is also applied.

Feb 1, 2024

By Ian Farrell, Josh Stowe, Eric Wingeard

Tailings transport system design is generally based on identifying the minimum and maximum process boundary conditions for pump selection and pipeline sizing. The approach is robust and well-proven. However, the approach has the potential to skew selections to operating scenarios that have a very low likelihood of occurring, such as the combination of high solids throughput and low tailings solids concentration. The approach can result in a tailings transport system design that is overly conservative. A probabilistic method-based approach captures the independent variability of design inputs and the combined likelihood of outcomes. This approach identifies the process conditions that have the highest likelihood of occurrence and are most applicable to equipment and pipeline selections. An outline of a probabilistic-based approach to tailings transport system design and the resulting selections is provided in this article. The probabilistic-based system design is compared to the outcomes from the traditional approach. The benefits and challenges to this approach are discussed and recommendations for utilizing this approach for tailings transport system design are provided.

Mar 31, 2021

By P Knights

This paper examines the process and specialised skills required to extract insight from data routinely collected by mine operations, maintenance, engineering and environmental departments. Typical insights include: enhanced understanding of root causes; recommendations for next best actions; and simulation of likely scenarios. The skills required for advanced analytics are not currently the domain of mining engineers. The professions required by tomorrow’s mines are likely to be diverse and multi-disciplinary, and will include control engineers, software engineers, mathematicians and statisticians. A case study is presented that correlates mobile equipment production delays with rainfall events across three mines on the east coast of Australia. One mine is shown to have significantly more rain related downtime than the other mines, providing compelling evidence to improve productive performance.

Nov 22, 2011

By José Brant, Douglas Torres, Rogério Navarro, Rodrigo Souza, Eduardo Brocchi

The steelmaking process requires the input of ferro-alloys to implement the adjustment of some elements composition in the final product. In the particular case of stainless steel production, the high carbon FeCr alloy stands out as one important precursor. However in the production of this material a certain quantity of fine powder with remarkable chromium and carbon content is also generated, which, in turn, could be processed through alkaline roasting in order to selectively recovery this element in a subsequent aqueous route. In the present work, this process is investigated, using excess of NaOH as oxidizing agent, and H2O2 for precipitating chromium as Cr(OH)3, which is next calcinated to Cr2O3. According to the results, the global achieved recovery has shown to be around 98%, suggesting that the proposed route can be seen as a potential process for chromium oxide production from the mentioned fine powder.

Jan 1, 2015

By Robert M. Becker

This investigation (in five parts) extends the theory of sample reliability from a sample consisting of a fixed number of items to a sample consisting of a fixed amount of items. Examples of a fixed amount of items per sample are samples consisting of a fixed weight or a fixed volume of unequal size particles. The extension of the theory is confirmed by experimental laboratory sampling using standard procedures. The probability distribution functions (the binomial, hypergeometric, multinomial, generalized hypergeometric, and those here called the compound binomial and compound multimomial functions) are developed from fundamentals. Their distributions are generalized to include some measured characteristic of the items. Infinite population moments are derived from moment-generating functions, and finite population moments are developed from corresponding infinite population moments using a newly defined mathematical operation. The first three experimental moments in laboratory sampling to given weights of particles are compared with the theoretical moments of their corresponding compound mult.inomial distributions. The agreement is striking. The study is divided into five parts. Part 1 deals with probability or random sampling to n items and with all sampling to n items per sample from some one probability distribution. This is the area of sampling covered by well-known theory. Accordingly, the procedures may be different but many of the results are well known.

Dec 1, 1964

By R. Hogg

"The basic population balance models for agglomeration processes are reviewed and procedures are described for extending their applicability to systems with size-dependent rate constants and to the formation and growth of porous agglomerates from rigid, solid particles. Simplified procedures for the further extension of the models to include simultaneous agglomerate growth and breakage arc also described. IntroductionThe association of small particles into clusters or agglomerates is a significant factor in many facets of particle processing. Agglomeration processes are widely used to facilitate handling, storage and utilization of fine powders. Processes such as coagulation or flocculation are used to aid solid-fluid separation in dispersed particulate systems. Agglomeration also occurs as an accompaniment, often unwanted, to other particulate processing operations such as fine grinding, mixing and blending, transport and flow.Reliable agglomeration models are needed for improved understanding of the processes in general and of the complex role of numerous, interacting variables as well as for direct application to the design and control of industrial processes such as flocculation, granulation and pelletization. Ideally, the models should account for the primary forces responsible for agglomerate ·formation and growth, the effects of external forces on process dynamics, the development of agglomerate structure and its role in the process itself, and the effects of concurrent processes such as structure modification (e.g. compaction) and agglomerate breakage or degradation.In its most general form, the process of agglomeration involves taking discrete, independent particles, bringing them into contact with one another, promoting (or allowing) interparticle adhesion to occur and then causing structure rearrangement, usually under the action of external forces. The relative importance of these steps varies with the nature of the particulate system being agglomerated and with the kinds of agglomerates being produced. Coagulation or flocculation of particles dispersed in fluids is generally dominated by the contact and adhesion steps. In the granulation of powders, on the other hand, particles are already in contact so that structure rearrangement is the principal step."

Mar 1, 1992

By Danqing Gao, Brijes Mishra

Spatial variance of rock properties is an important characteristic of rock which addresses the heterogeneity of mechanical and physical properties and their effect on underground mining. Assessing spatial variance can be useful for both locating potential difficult grounds and performing reliability analysis in the mining support system. This study shows a microscale numerical model for rock material based on continuum mechanics. To consider the spatial correlation factor of mechanical properties in realistic rock mass, this study introduces a spatial correlation concept into the traditional type III extreme value distribution model. Based on the improved microscale random model, we conducted a series of numerical uniaxial compressive tests and one longwall mine model to investigate the progressive failure of rock. The results show that spatial correlation factor can significantly affect the load-deformation curves and fracture patterns. The spatial variance model was applied to a longwall mine that included several cutting sequences to observe the influence of the spatial variance on roof behavior. The cohesion and friction random fields induced failure that propagated randomly through the immediate roof in different entries. The results showed that the spatial variance provides an accurate prediction of erratic roof falls in coal mines.

Jul 20, 2020