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By W. S. Ayres

I. INTRODUCTION. THIS cavern was discovered Oct. 22, 1904, by Mr. Charles H. Deutschman, in company with whom I made, May 29 to June 3, 1905, at the request of Mr. Howard Douglas, Superintendent of the Canadian National Parks, the first exploration of it for the Canadian government. The results were stated in a paper, orally presented, with lantern-views from my photographs, at the British Columbia Meeting of the Institute, Victoria,, B. C., July 5, 1905.* The present paper embodies also the results of a second examination, made Oct. 25 to 29, 1905. The accompanying map, Fig. 1, will serve as a guide to the following description. II. LOCATION. The cavern is situated at snow-line, at the head-waters of Cougar creek, on the west slopes of the Selkirks, about 2 miles north from Ross Peak water-tank, and 5.5 miles west from Glacier House, on the main line of the Canadian Pacific Railway. It was then reached by an arduous climb from the water-tank, up the ravine of Cougar creek, for 8,000 ft. (2,000 ft. of altitude) over rock- and snow-slides, and through a thick tangle of alders. But an easy and very picturesque trail has, during the past summer, been opened by the government from Glacier House. Figs. 2, 3 and 4 represent views, not heretofore published, of the grand scenery of this region, so rapidly becoming the-object of attraction to thousands of tourists from all parts of the world. These views, as well as those shown in. Figs. 5, 6, 7, 8

Jan 1, 1907

By L Manca, P B. Hills, D Tyler, N Pollington

This paper describes a collaborative project undertaken by Newcrest Mining Limited (Newcrest) and pitt&sherry to identify, develop and then implement global best practices to manage the exposure to inrush (dry and mud) hazards in underground mining operations. An extensive literature review was undertaken to identify past experience globally and the current state of knowledge and practice in managing inrush hazard. A key requirement of the literature review was the development of a list of guiding questions which would form a framework for approaching operators to discuss the topic, capture recent learnings and understand current operating practices to allow the development of a best practice solution. An initial cohort of 14 mines across four continents chose to contribute and detailed interviews were carried out by the project team. The outcome from the literature review, interviews with participating mines and various internal discussions was a comprehensive summary document detailing Basic versus Best Practice management of the inrush hazard. This document is being used as a gap analysis tool by Newcrest to assess and guide the management of inrush hazard at their existing and future operations. The summary document has also been provided to the participating mines for their consideration. The project is iterative and will continue to evolve as new experiences, knowledge and practices come to light.

Mar 15, 2021

By Pedro Pablo Vasquez Coronado, Victor Octavio Tenorio

"Productivity in openpit mines depends on the observation and adjustment of critical phases of operation. As one of the most expensive activities in openpit production, optimization of the load-haul-dump cycle becomes a critical aspect to address. Using simulation techniques and an ad hoc methodology for analyzing the key performance indicators (KPIs) involved in the production cycle, it is possible to compare actual performance and ideal operating conditions and develop an alert system when operating conditions are subpar with the expected production standards.Study objectivesThe purpose of this work is to implement a methodology for optimizing the haulage cycle by identifying and adjusting the factors that affect the cycle time performance. The methodology includes the implementation of an alert system emitting warning messages when one or several trucks are idle, or when the time of completing production tasks is falling outside a predefined value. This alert is compared with predefined KPIs and is used to determine corrective actions.The alert will:• Demonstrate the benefits of time analysis and how this affects the productivity results in the mining process.• Demonstrate the utility of KPIs in the extraction of ore and waste and how they help to identify equipment performance.• Develop software interfaces to visualize the alert system in order to increase awareness in the operations supervisor.• Make recommendations for future applications that can help improve the productive process of an openpit mine.Problem statementTransporting material in openpit mines may require the utilization of high capacity equipment, which also represents an elevated cost per hour. A supervisory system that controls the adequate distribution of trucks and shovels by providing the operational status of each unit shall contribute to increase productivity while subsequently reducing operational costs. Nevertheless, there is an issue with certain dead times such as queue trucks for loading, trucks waiting to be loaded and other delays. This creates inefficiencies in fuel consumption and energy utilization.For the identification of delays, a contextbased system could be required in order to help optimize the haulage cycle time by controlling delays in loading, haulage and dumping. After applying this methodology, efforts were focused in correcting out-of-standard performance values."

Jan 1, 2015

By V. O. Tenorio, P. P. V. Coronado

"INTRODUCTION Productivity in Open Pit mines depend on the observation and adjustment of critical phases of operation. As one of the most expensive activities in Open Pit production, optimization of the load-haul-dump cycle becomes a critical aspect to address. Using simulation techniques and an ad-hoc methodology for analyzing the Key Performance Indicators (KPIs) involved in the production cycle, it is possible compare actual performance and ideal operating conditions and develop an alert system when operating conditions are sub-par with the expected production standards. STUDY OBJECTIVES The purpose of this work is to implement a methodology for optimizing the haulage cycle by identifying and adjusting the factors that affect the cycle time performance. The methodology includes the implementation of an alert system emitting warning messages when one or several trucks are idle or the time of completing production tasks is falling outside a predefined value. This alert is compared with pre-defined Key Performance Indicators (KPIs) and determine corrective actions: • Demonstrate the benefits of time analysis and how this affects the productivity results in the mining process; • Demonstrate the utility of KPIs in the extraction of ore and waste, and how they help to identify equipment performance; • Develop software interfaces to visualize the Alert System in order to increase awareness in the operations supervisor; and • Make recommendations for future applications that can help improve the productive process of an Open Pit mine. PROBLEM STATEMENT Transporting material in Open Pit mines may require the utilization of high capacity equipment, which also represents an elevated cost per hour. A supervisory system that controls the adequate distribution of trucks and shovels by providing the operational status of each unit shall contribute to increase productivity and subsequently reducing operational costs. Nevertheless, there is an issue with certain dead times such as queue trucks for loading, trucks waiting to be loaded, and other delays. This creates inefficiencies in fuel consumption and energy utilization. For the identification of delays, a context-based system could be required in order to help optimizing the haulage cycle time by controlling delays in loading, haulage, and dumping. After applying this methodology, efforts were focused in correcting out-of-standard performance values."

Jan 1, 2016

By A. Morrison, P. Brito-Parada

"The separation of valuable and gangue minerals according to their surface hydrophobicity in a froth flotation tank occurs in both its pulp and froth phases. In the pulp phase, hydrophobic particles must be brought into contact with rising bubbles introduced at or near the bottom of the tank. In a mechanical froth flotation tank, this is primarily achieved through the agitation of the pulp by an impeller or by a rotor-stator system. However, the turbulent and mixing effects of such an impeller or rotor-stator system, necessary to promote bubble-particle interactions in the pulp, are not confined to the pulp zone, but are transmitted into the froth zone at the pulp-froth interface. This impeller-induced turbulence at the pulp-froth interface is compounded by the impulse of buoyant bubbles entering the base of the froth phase, reducing the stability, and thus separation performance, of the resulting froth. Hence, turbulence improves separation performance if it occurs deep in the pulp phase, but diminishes it if it occurs close to the pulp-froth interface. For this work, a performance-enhancing pulp phase insert was designed to isolate the impeller-induced turbulence from the pulp-froth interface in a laboratory-scale, continuously-operated froth flotation tank. The result was a shifted grade-recovery curve that allows the insert to be designed to maximize the recovery from the system without sacrificing the grade of the concentrate, or vice versa, along a spectrum of improved performance. This paper will present the insert design and development process that resulted in this improved grade-recovery curve, as well as a set of heuristics that could be used to design a similar insert for pilotand industrial-scale validation and deployment.INTRODUCTIONAn almost ubiquitous design feature of commercial flotation tanks is the enclosure of the impeller to create a concentrated turbulent zone (Mavros, 1992). These turbulent zone enclosures are varied-- from the rotor-stator design of, for instance, Outotec cells, to the air disperser design of Wemco cells-- but all share the same rationale: that turbulence is desirable to promote bubble-particle interactions (Ralston, 1999), and to produce smaller bubbles (Wills, 2006), but also undesirable because it promotes the detachment of valuable mineral particles from bubbles, and exacerbates entrainment-inducing mixing at the pulp-froth interface (Jameson, 2010)."

Jan 1, 2018

By Li Xi

This paper describes how a back-propagation neural network is built for predicting the properties of engineering materials from their other properties, compositions or processes. A predicted result of the impact toughness of a 12Cr-2Ni-1.5Mo stainless steel from its tempering temperature is presented. Furthermore, the combination of this neural network for prediction is able to supplement the unpredictability of the expert system outside its domain of expertise. An integrated system may perform more intelligently and solve more complex problems as well as human expert, in some case even better.

Jan 1, 1992

By Reinol Compañero, Ivy Gonzales, Herman Mendoza, Brian Buenaventura

"The extraction of gold in the Philippines has been a significant challenge for the past decades. Around 70-75% of gold mined in the country can be accounted from the small-scale mining industry which primarily use the traditional cyanidation and amalgamation; processes which have been advocated due to its adverse affects to health and environment. To address this challenge, an alternative clean and sustainable technology was developed for the small-scale miners to recover gold and other metal/mineral values efficiently from Philippine ores. An initial survey was conducted and followed through with extensive mineralogical investigations ascertain the best method applicable. It was determined that Philippine gold occur in ore as (1) very fine particles in the microns range, (2) free-milling, which is in abundance, and (3) locked particles with sulfides --- it was concluded that enhanced gravity concentration and flotation are viable alternatives. A comprehensive test regime was followed to check the response of the ores obtained from different small-scale mining districts across the country. It was shown conclusively that the gold ores respond positively, with recoveries using gravity concentration and flotation of at least 95% and 88%, respectively; exceeding the nominal recoveries using cyanidation or amalgamation. A specific process flow was designed for each type of ore with customized parameters. It was determined that while capital expenditure of implementing these alternative processes is higher than what is currently being used, the operational aspects show that it is much more economical to apply enhanced gravity and flotation. It should be noted that the process developed addresses the critical issue of environmental costs which should be more than enough to justify the shift from the current to the novel and sustainable technologies."

Jan 1, 2014

By J. A. Herbst, K. Rajamani

INTRODUCTION Recent research has shown that popu- lation balance models hold considerabl e promise as a basis for accurate mill scale-up from laboratory batch grinding tests. It has been shown that entire product size distributions from large ball mills can be predicted from data obtained in tests in small mills with errors of less than one or two percent. This level of accuracy has been demonstrated for batch grinding scale-up (Herbst and Fuerstenau, 1980; Austin, 1973; and Malghan and Fuerstenau, 1976) and for continuous grinding scale-up (Herbst, et a1., 1976; Herbst, Rajamani and Sanchez, 1982; and Herbst, Rajamani and Lo, 1982) in commercial mills up to 14.5 x 32 feet. A procedure which has been proposed for commercial mill design using the population balance approach and specific power information is shown in Figure 1 (Herbst and Fuerstenau, 1980). Here batch grinding data (size distributions for various energy inputs) obtained in a small batch mill is input to an estimation program which determines the "best" set of breakage rate parameters from the data provided. In turn, these breakage rate parameters are input to a scale-up program along with traditional inputs such as: a) desired circuit throughput and product size b) circuit operating conditions including fraction of critical speed and fractional ball load, size distribution and % solids in feed and circulating load (if closed circuit). In addition, since the population balance approach relies on more detailed models of the grinding circuit sub- processes than the classical design methods do, it is necessary to provide input to the scale-up program on the nature of material transport through the mill (e.g. residence time distribution information) and classifier performance characteristics (e .g. selectivity functions). The scale-up program will make the design calculations including the selection of mill dimensions and drive requirements, will predict product size distributions throughout the commercial circuit and will provide information on the sensitivity of the design to errors in the design assumptions. In order to implement such a scale- up scheme it is necessary to have a computer program for parameter estimation and a program for scale-up prediction. A program which is suitable for parameter estimation, ESTIMILL, has been developed and tested on a wide variety of ores at the University of Utah. This program has been in use in

Jan 1, 1982

By J. Sattarvand, P. C. Augustine

Despite significant safety improvements, the mining industry remains one of the most hazardous occupations globally and the evacuation of Miners, when an uncontrollable incident occurs in the mine, is the best bet to saving lives. However, Human factors/behaviors during an emergency are likely to influence the evacuation performance. Other industries have made a significant effort to determine these human factors that can impede evacuation performance, however, the current state-of-the-art in mine evacuation or self-rescue is that the evacuation route is predetermined, and a static sign is used to direct miners to the predetermined safe location. This method is limited in representing actual conditions that arise in a real emergency, neglecting the different behaviors displayed by humans. As optimization of the evacuation of a mine plays a fundamental role in emergencies and modeling evacuation behavior and movement of miners is a complex task, this research utilized Agent-Based simulations to simulate the evacuation behavior and performance. It was observed that people with the smart evacuation device made fewer mistakes and arrived at the safe place in less time compared to those have no access to the device. The Mathematical model used in optimizing the shortest path to a safe place is also explained in this paper.

Jun 25, 2023

By L D. Munro, S A. Jackson

This paper provides a logical approach to developing a TSF design concept through: • Identifying key properties of tailings and containment structures; • Reviewing underlying principles for effective operation; • Showing how these apply to select an appropriate TMS; and • Demonstrating how to align the TMS to site-specific constraints and TSF design. This approach follows a path of rigorous data analysis independent of discharge parameters (whether low-density slurry, paste or cake disposal) to select the most cost-effective and sustainable approach for any given material or site.

Jul 1, 2021

By Fleming, R. C.

ONE OF THE NEWEST developments of industry rising from the commercial application of scientific knowledge is in the making of solid carbon dioxide from the gas about 1925 the first efforts were made to manufacture "dry ice" on a large scale and at a price to permit widespread use. From that beginning the industry has grown to a consumption of 40,000 tons in 1930. Carbon-dioxide ice, as the name implies, is merely the gas compressed and cooled to a solid. The ice has a temperature of 109° F. below zero and is in many ways superior to water ice. It evaporates to a gaseous form so it is not wet and leaves no trace; in fact, one suggested minor use is as coasters under water glasses on the dining table. The gas is harmless except in large concentrations and. when the ice is used as a refrigerant, the resulting gas actually becomes a preservative, keeping oxygen away from perishable products. Not only does the ice have a greater amount of cold in a small volume than water ice but cooling is effected by direct contact of the resulting gas with the materials to be refrigerated rather than by convection air currents.

Jan 1, 1932

By J. Navoyski, B. Macdonald, W. J. Helfrich, J. L. Bellanca, B. Demich

DISCLAIMER The findings and conclusions in this paper are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of company names or products does not constitute endorsement by NIOSH. ABSTRACT Recent advances in computing, rendering, and display technologies have generated increased accessibility for virtual reality (VR). VR allows the creation of dynamic, high-fidelity environments to simulate dangerous situations, test conditions, and visualize concepts. Consequently, numerous products have been developed, but many of these are limited in scope. Therefore, National Institute for Occupational Safety and Health researchers developed a VR framework, called VR Mine, to rapidly create an underground mine for human data collection, simulation, visualization, and training. This paper describes the features of VR Mine using self-escape and proximity detection as case studies. Features include mine generation, simulated networks, proximity detection systems, and the integration and visualization of real-time ventilation models. INTRODUCTION There are many definitions of virtual reality (VR) that include various levels of immersion and features [1]. Some definitions refer to specific technologies [2], while others are limited to visualization [3]. For this paper, a more general definition of VR will be adopted. VR is defined as the collection of hardware and software that interactively engages users and stimulates their senses within a synthetic or virtual environment. From a hardware standpoint, this can include anything from a phone to a head-mounted display (HMD) to a large-scale theater as well as speakers, microphones, haptic sensors, and interaction devices. The software used to create virtual environments (VEs) generally includes a game engine, custom software components and libraries, and two-dimensional and three-dimensional graphical assets. Recent hardware and software advances have increased the fidelity and availability of VR. New and improved technologies including HMDs and high-resolution monitors and projectors can display sharper, more detailed visualizations. For example, in the past five years between the release of the Oculus Rift DK1 (2013) and the HTC Vive Pro (2018), there was a three-fold increase in resolution along with a 50% increase in the refresh rate. Furthermore, despite early claims that low-cost VR technology was readily available [4], computational power has not been sufficient to handle the large amount of data generated by these systems [5]. In the past five years, however, rendering speeds have more than doubled and memory has more than tripled [6], allowing these visualizations to be incorporated into higher-complexity and -fidelity VEs that more closely mirror the real world. Similarly, software capabilities have also significantly improved through game engine advancements and feature development. In the past several years, game engines have added and improved features such as physics, lighting, platform support (e.g. Android), and asset development integration. Some of the current leading commercial game engines are Amazon Lumberyard, CryEngine, Unreal, and Unity, but this can quickly change as is evident in the literature [7, 8].

Jan 1, 2019

By Brendan Demich, Brendan Macdonald, Timothy J. Orr, Jason Navoyski, Jennica L. Bellanca, William J. Helfrich

Recent advances in computing, rendering and display technologies have generated increased accessibility to virtual reality. Virtual reality allows for the creation of dynamic, high-fidelity environments to simulate dangerous situations and test conditions and to visualize concepts. Consequently, numerous products have been developed, but many of these are limited in scope. Therefore, U.S. National Institute for Occupational Safety and Health (NIOSH) researchers developed a virtual-reality framework, called VR Mine, to rapidly create an underground mine for human data collection, simulation, visualization and training. This paper describes the features of VR Mine, including mine generation, simulated networks, proximity detection systems, and the integration and visualization of real-time ventilation models.

By S Dykes, R J. McCarthy, B Klein

There is growing interest in the mining industry on the application of ore sorting. While many are familiar with particle sorting, including the limitations that technology presents (e.g. throughput), bulk sorting, with its higher throughput potential, is less understood. Despite the potential to sort at higher throughputs, few operations have adopted bulk sorting processes, certainly not at large scale. It is suggested that the inability to reliably predict outcomes from bulk sorting may be limiting its adoption in mining projects. Consequently, an evaluation approach for bulk ore sorting has been developed such that mass pulls and grade upgrades can be predicted in the context of a mining study. The approach allows for evaluation of drill core assays and application of the consequently derived heterogeneity relationships to the block model for estimation of sorting outcomes. These processes were applied to conveyor-based bulk sorting for the CuMo project in Idaho, USA and are described in this paper.

Nov 10, 2020

By Sadegh Elyasi

TBMand roadheader are two dominating excavation machines in underground tunnelling projects. The performance of these two tunnelling machines has been reviewed and analysed individually by many researchers from multiple points of view. However, there are almost no studies that have made an extensive comparison between these two machines, mostly from financial points of view. The current study is intended to characterize both financial and technical status of these two mechanical tunnelling machines in one of the biggest coal mines in Iran. The main objective of this study is to define the best method and equipment that meets a predefined economic goal, which is mainly to maximize the net present value. To this end, a technical and financial model based on the geomechanical and financial parameters involved in the project has been prepared and the financial part of the project has been carried out by applying COMFAR III financial analysis software. Subsequently, a sensitivity analysis of the model was conducted in order to evaluate the effect of involved parameters on the project. According to the results, a roadheader has better economic justification than a TBM, while the TBM has a better advance rate than the roadheader.

Feb 12, 2021

By J. C. Gathje

The Robinson copper ores were mined for many years from pits containing varying ore grades, sulfide and oxide ore types, and differing mineralogy. The ores also contain gold and molybdenum values, and their recoveries are an integral part of the flowsheet development. Metallurgical responses were characterized using a standard flotation procedure. Further studies investigated primary and regrind particle sizes, reagents, and other variables. The metallurgical testing was supported by mineralogical studies. Results demonstrated a high degree of metallurgical success for flotation. Final copper concentrates ranged in grade from approximately 28 to 30% copper and copper recoveries were 89 to 95% based on laboratory and pilot plant data.

Jan 1, 1992

By W. S. Hegler

Introduction The San Antonio mine is on the north shore of Rice lake, thirty miles east of lake Winnipeg and 120 miles northeast of the city of Winnipeg. Since production was started in 1932, about 2,000,000 tons of ore have been mined. Currently in progress is an extensive development programme which involves 11,500 feet of crosscuts, 3,800 feet of raises, 1,753 feet of shaft sinking, and 160,000 cubic feet of slashing, all in footwall waste rock. It is the purpose of this .paper to indicate the necessity for this work and to describe the methods employed to carry it out. Where unknown factors are as prevalent as they are in the average Canadian gold mine, a definite answer cannot be given as to what is the most economical and efficient system for mining dipping deposits. At San Antonio, the host rock for the orebodies, locally termed basalt, occurs as a sill some hundreds of feet in width and dipping at approximately 45 degrees from surface to an unknown depth. It may be assumed that it continues well below the lowest depth established to date by diamond drilling. At present, a vertical winze (No. 3 winze) hoists the ore from the 2,360-foot level to the 1,600-foot level, on which it is hauled about 900 feet to No. 3 shaft, also vertical, and there hoisted to the mill bins on surface. To maintain ore reserves at a five-year figure, at full production, additional deep exploration was required immediately. It was decided to sink No. 4 winze, a vertical opening of the same size as the other operating shafts, to provide ten additional levels (17 to 26) at 150-foot intervals, with additional depth to allow for an underground crusher installation and usual loading-pocket facilities for three-ton skip-hoisting. The winze was bottomed at 1,753 feet below the collar, at a depth of 4,117 feet below surface, and is the deepest man-sized opening in Manitoba.

Jan 1, 1949

By W. C. Yates

Lack of visibility from large, open-pit haulage truck cabs has become a serious safety problem. Anaconda conducted a research program to develop a low cost system to alert haulage truck operators to small vehicles present in blind areas. Several systems were developed and tested. As open-pit haulage truck size has increased, so has the size of the blind areas. Mine utility vehicles, pickup trucks, and cars are concealed within these blind areas and become safety hazards. Figure 1 shows the typical blind areas of a 136 t (150-ton) haulage truck. The areas of greatest concern are at the rear center and front right corner of the truck. In these "no visibility" areas many small vehicles have been crushed by large haulage trucks at various mine sites. In most instances, the occupants escaped the vehicle before it was destroyed. But injuries and death have occurred. In most cases, the accidents were attributed to negligence or carelessness by the small vehicle driver. The limited visibility problem still exists, though, and a solution is needed. Initial Solution The usual plane mirror on the driver's side and the convex mirror on the right front of the haulage truck allow only limited rear visibility. The typical, right side convex mirror is generally small and difficult to locate at a glance. This convex mirror also presents an image that distorts distance perception. These mirrors are of¬ten broken and immediate replacement not demanded or made. The US Bureau of Mines, in a contract with M.B. Associates, San Ramon, CA, developed an improved visibility system. It consisted of a larger, left view mirror and unique, blind area viewer. The large 230 x 690 mm (9 x 27 in.) left mirror has a small convex spot mirror near the bottom. The entire unit can be quickly replaced if broken. The large size provides a full view of driver orientation features such as the rear tire and the top of the load bed. The right 300 x 410 mm (12 x 16 in.) mirror has a convex surface and is quite rugged. The 510 mm (20 in.) spherical radius presents the operator with some distance distortion, but objects in its view are easily seen. The "blind area viewer" consists of a modified fresnel lens that allows the driver to "look around the corner." Installation of three of these lenses on the front of each haulage truck is rec¬ommended for adequate blind area coverage. This system significantly increases an operator's field of view and allows viewing of objects within about 3 m (9.8 ft of the truck. Many open-pit mines are nor mounting on smaller vehicles a long whip with a flag and lamp or both. This increases vehicle visibility to haulage truck operators. The whip is permanently attached to the mine vehicle. It can also be magnetically attached to transient vehicles. The whip system. though, is inadequate for visibility in the critical rear and right front blind areas. Alternate Solutions All of these visibility aids as¬sume an attentive driver. In addi¬tion, areas such as the rear blinc, area are not covered. Based on the inadequacy of existing visibility systems, Anaconda made a com mitment to further the truck de¬tection technology. The best ap¬proach was considered to be ar active system. It would notify the haulage truck operator that an en¬croaching vehicle is present. Sev¬eral systems were considered, in¬cluding ultrasonics and elec¬tromagnetics. For the ultrasonic system, com mercial and in-house design were looked at. Designing an( building transducers with the spe cific beam shape to match the haulage truck blind spots re¬quired a major technological breakthrough. False alarms ap¬peared difficult to prevent en¬tirely. They were caused by pass¬ing, trailing, or leading vehicles a., well as nonthreatening objects. As a result of these problems, the ul¬trasonic technique was not pur sued. An alternative, an electro

Jan 7, 1982

Production targets are the basis for almost every decision made by operations personnel in the daily operation of a concentrator. It is the production targets that determine how the plant is operated and therefore determine its efficiency. However, to achieve maximum plant efficiency production targets must be relevant to the process and achievable.In RoseberyÆs case, for many years, production targets were taken from budget data which, with the exception of mill feed tonnes and grades were carried forward from the previous budget. The zinc concentrate grade target was fixed at 57 per cent Zn, a long-term average; it was the accepted æstandardÆ for Rosebery. Historical data showed this target was never consistently achieved and plant efficiency was highly variable.Investigations into the possible causes for the variable performance ruled out plant and mechanical issues. Despite the Rosebery concentratorÆs age the plant and equipment are more than serviceable and reliable. The mineralogy of the ore and specifically the iron content of the sphalerite was found to be the most significant determinant of zinc concentrate grade. It was found with increasing frequency that the zinc grade of the sphalerite in the ore was below the zinc concentrate grade target. Consequently on these occasions attempts to meet the required concentrate target destabilised the process resulting in plant inefficiencies.Using the correlation between iron and zinc, data modelling was able to accurately predict the maximum zinc concentrate grade achievable for any ore type. By using on stream analysis instrumentation the operations personnel are now provided with constantly updated concentrate grade targets. By knowing the mineralogical limits of the ore at the time it is being treated process stability is maintained allowing plant efficiency to be optimised. This has resulted in a step change in plant performance and a significant increase in revenue.CITATION:Harris, G R, 2012. Developing and implementing ore-specific targets for the Rosebery Concentrator, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 321-324 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By D J. Brake

The importance of mine ventilation to health and safety in both coal and metalliferous mines has been long recognised. The primary and secondary ventilation systems in most metalliferous mines incur 50 per cent or more of the total mine electrical power consumption and frequently about 10 per cent of total underground mine operating costs. The requirements for ventilation-related horizontal and vertical development, fans and cooling have a significant impact on mine capital costs and also on mine schedules and start-up times and hence cash flows. There are increasing pressures on regulators and miners to reduce airborne contaminants such as diesel particulatematter, nitrogen dioxide and heat (wet bulb temperatures), and significant pressures to reducegreenhouse gases such as fugitive methane emissions from coalmines and the carbon dioxide footprint of both coal and metalliferous mines. Many previously Australian miners are now globaloperators and have extensive overseas mining operations where local ventilation standards and expertise may not be consistent with Australian practices. The role of the site ventilation officer is also changing with strict new requirements for the statutory position being introduced into Queensland metalliferous mines and the potential for this to become more widespread. Recent regulator and parliamentary review committees have identified systematic shortcomings in mine ventilation compliance, and statutory certificates in both Queensland and NSW now require continuing professional development to maintain currency. Public and investor support for mining are also increasingly contingent on safe, healthy and environmentally responsible practices and the standards for these are frequently tightening. Good ventilation design and operating practices that are consistently well executed therefore contribute significantly not only to a safe and healthy mine but also to a productive and cost-effective operation and the ongoing social licence to operate. There are a variety of ways of providing technical design and oversight into a mine’s ventilation systems; this paper explores some current trends in ventilation standards and statutory requirements, as well as ways to support and develop mine ventilation staff for both domestic and international operations and also the emerging senior technical roles of Group/Principal/Corporate mine ventilation engineer.

Oct 12, 2022