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By S. T. Murray

The European industrial minerals industry and its markets are largely self-sufficient. The companies who are members of the Industrial Minerals Association (IMA-Europe) number around 150 contributing 5 billion Euros to the EU?s GDP and range in size from global publicly quoted corporations to small family owned private companies. Their means and capability to implement sustainable development vary considerably. However the leading companies provide an excellent set of best practices, which IMA as a trade association with recognised core competencies in the field of sustainable development is ideally placed to promulgate throughout its membership. As an active participant in the EU Voluntary Scheme for SDI reporting IMA is not only working to increase the level of response to the SDI questionnaire but is also developing with its members a new sustainable development charter which its members will voluntarily adopt as a guiding principle for their implementation of sustainable development This work will be a consultative process involving all IMA?s section members as well as other trade associations, NGOs and MEPs. Public awareness of the benefits of minerals and their contribution to sustainable development has been raised by IMA?s awareness campaign now being followed by a more targeted programme aimed at MEPs. Further work in the future will consider product stewardship and life-cycle analysis. IMA is already positioning itself with the help of its members to assimilate the minerals industry of the accession territories in the sustainable development process.

Jan 1, 2003

By Robert G. Lundguist

REAM is a unique and promising method of rock breaking using high energy, inert projectiles to impart mechanical energy to the rock. This paper describes a demonstration of the application of this new technology to two specific problems in open pit mining: secondary breakage and the scaling of loose material from pit walls. Under previous government contracts, Physics International Company developed the projectile impact method for a large variety of commercial and military rock excavation tasks. A 4 meter (13 foot) diameter by 16.8 meters (55 foot) long tunnel was driven at the Hope Valley Mine in the Sierra Nevada mountains of California in 1972 and 1973. An average of 1100 kg (1 ¼ tons) of a 172 MN/m2 (25,000-psi) granodiorite formation was broken by each of 590 shots used to drive the tunnel.l Based on these results it is estimated that REAM can drive over 60 meters (200 feet) of tunnel per day at about 88 percent of the cost of drilling and blasting. In addition, repeated axial impact by high energy projectiles was used to drill a 0.4 meter (16 inch) diameter horizontal hole in the same granodiorite formation. Each shot advanced the hole an average of 0.2 meter (8 inches).

Jan 1, 1976

By D. V. Bush

The economic application of real time computer control can be broken down into 2 broad areas of concern. The first would be in gaining the most efficient utilization of energy. The second would be in improved product quality. This paper will be primarly concerned with the first area of efficient energy utilization as that area has the greatest effect on costs and thus net profits. Most process control strategy attempt to achieve the greatest comminution with the least amount of energy thus maximizing efficiency. A more direct approach to energy control involves a total mine and mill energy management system. In most cases these systems have an ability to achieve a very short payback period with the greatest return on investment.

Jan 1, 1986

By P. Somasundaran

Previous studies on semi-soluble minerals such as calcite (1) and apatite(2) and sparingly soluble minerals such as quartz (3,4) have given evidence for significant changes in their electrokinetic properties as a function of aging time. Such changes are relevant to mineral processing operations where the crushed ore particles might not have yet reached equili¬brium with the water that it is in contact with. In order that these changes be studied under controlled experimental conditions for long periods unattended or with fairly less intermittant attention, a streaming potential apparatus with an automatic streaming system was constructed. Also, a new streaming potential cell was incorporated into the system so that the effect of temperature, a variable coming into increasing usage in mineral processing operations(5), could also be studied. Conventional streaming cells(6) cannot be safely employed to conduct studies as a function of temperature since they have many glass joints that are prone to leakage, parti¬cularly under pressure, in the course of an experiment. This paper describes the new apparatus and some typical results that have been obtained with it far temperature effects.

Jan 1, 1973

By C. A. Fleming, K. W. Sarbutt, P. K. MacPhail

The SART process has been developed for Teck to treat bar­ren solution from the cyanidation/CIP process that has been developed for the Lobo-Marte project in Chile. The objective of the process is to recover cyanide in a form that is suitable for recycling to the leaching part of the process. The Marte and Lobo ore bodies require a dosage rate of about 2 kg/t NaCN, of which only 0.5 kg/t is truly consumed (as thiocyanate, cyanate and ferrocyanide species). The remaining -1.5 kg/t is present as cop­per cyanide (-1 kg/t) and free cyanide (-0.5 kg/t), and is poten­tially recoverable and recyclable. SART is an acronym that describes the unit operations in this cyanide recovery process; namely, .. Sulphidization .. Acidification .. Recycling of precipitate " Thickening of precipitate The basic chemistry has been applied previously, and has also been the subject of two patents (American Cyanamid Company, 1965, Potter et al., 1986). The process involves the conversion of all free and WAD cyanide in solution to hydrocyanic acid by acidification of the tailings solution to pH :s,4, and the conversion of all copper in solution to cuprous sulphide (synthetic chal­cocite) by the addition of a sulphide salt:

Jan 1, 1998

By Peter Zhang, Daniel Su, Berk Tulu, Bo Hyun Kim, Zoheir Khademian

Over 2,000 shale gas wells have been drilled in the Pittsburgh Seam longwall reserves. As longwall panels are laid out, some of these shale gas wells must be located in longwall chain pillars. With longwall mining on both sides and the constraint of chain pillar size, gas well in chain pillars are subjected to longwall-induced ground movements and stresses, which could induce deformations in gas well casings Casing deformations are associated with several factors such as overburden geology, surface topography, setback distance, and casing construction. Overburden geology is one important factor that largely determines the locations and levels of deformations in gas well casings Previous NIOSH gas well research has found that casing deformations above the coal seam horizon are smaller under deep cover than unde shallow cover and that casing deformations could occur at the coal seam horizon under deep cover. Recent mine-by cases have provided more insights into the locations and amount of longwall-induced casing deformations as well as the potential occurrence of a large casing deformation at the coal seam horizon. This paper presents three recent mine-by cases with shale gas wells in the chain pillars between two adjacent longwall panels under different overburden depths. Casing deformations were measured by multi-finger caliper surveys and predicted with numerical modeling. With the established numerical model, the effect of overburden depth was further analyzed to investigate the potential occurrence of a large casing deformation at the coal seam horizon under deep cover. These mine-by cases not only provide a general demonstration of how overburden depths can affect longwall-induced stresses and deformations but also give a good indication about the level of casing deformations that could occur under different overburden depths. The study concludes that (1) casing deformations reduce with increase of overburden depths at the gas well; (2) a cementing alternative with production casing uncemented is an effective means to eliminate production casing deformations; and (3) large plastic casing deformation could occur in the production casing at the coat seam horizon under deep cover. The experience and knowledge gained from these mine-by cases would help longwall operators and gaza companies to take appropriate measures to minimize the influence of longwall mining in shale gas wells in chain pillars.

Jun 25, 2024

By C. D. Litton, I. E. Perera

Experiments were conducted to evaluate the response characteristics of commercially available gas, smoke and flame sensors to fires of common combustible mine materials. The experiments were conducted in the large-scale fire gallery located at the National Institute for Occupational Safety and Health (NIOSH) Lake Lynn Laboratory in Fairchance, PA, using ponderosa pine, red oak, Douglas fir, high and low volatile coals, polyvinyl chloride (PVC) and styrene butadiene rubber (SBR) conveyor belts, No. 2 diesel fuel and diesel exhaust. All the experiments (except those using No. 2 diesel fuel and the diesel exhaust tests) were conducted in a similar manner, with combustible materials heated rapidly by electrical strip heaters, producing smoldering fires that quickly transitioned into flaming fires. The sensors included a diffusion-type carbon monoxide (CO) sensor, photoelectric- and ionization-type smoke sensors, a video smoke/flame detector and an optical flame detector. Simultaneous measurements were obtained for average gas concentrations, smoke mass concentrations and smoke optical densities in order to quantify the levels of combustion products at the alert and alarm times of the sensors. Because the required sensor alarm levels are 10 ppm and 0.044 m-1 optical density for CO and smoke sensors, respectively, the different sensor alarms are compared to the time at which the CO and smoke reached these alarm levels (Litton et al., 1991). In addition, the potential impact of using smoke sensors that have met the performance standards from accredited testing laboratories is also evaluated using the response of an Underwriters’ Laboratory (UL)-approved combination photoelectric/ionization smoke detector. The results are discussed relative to fire sensor needs that can have a positive impact on mine fire safety.

Jan 1, 2014

By S. Guo

In this paper, a model for the resin anchor bolt system is developed in which the smooth bar is modeled by using one-dimensional truss elements and the resin annulus is modeled by using axisymmetric elements. These two submodels are combined together and then incorporated into the' existing computer code ROOFBOLT. After this development, all of the components in the resin anchor bolt system including smooth bar, bearing plate and resin annulus can be correctly modeled.

Jan 1, 1995

By R. R. Smith

The meaning of the title, "Blank Piece of Paper," refers to the need for management to take a completely fresh viewpoint to the problems facing our industry. These problems are so severe and some so new that conventional thinking may not be adequate to resolve them. Innovation has to be a part of every company's approach to the solutions, our concept is to start with a "Blank Piece of Paper.' The objective of 'this paper is to outline steps which can be taken to improve the profitability of a mining business. This is not an examination of technical solutions to individual problems, but rather recommendations for overall change in management thinking. This philosophy is based on our actual, hands-on experience in major open pit operations worldwide over the past 25 years.

Jan 1, 1987

By Cory Bolen, Nadav Bar-Yaakov, Eric Zimmerman, Gregory Raines

The Chimney Hollow Reservoir Project broke ground in August 2021, constructing the tallest Asphalt Core Dam in North America, intending to improve reliability of drinking water supply to Northern Colorado communities. Aiming to expedite and streamline the geological mapping process in the tunnel, Stantec’s teams have developed a mobile and web-based GIS application for digital mapping input and rock mass evaluation, allowing real time decision making for assigning tunnel support class and resulting in a faster more efficient process. The following article presents and demonstrates the GIS mobile and web application-based process, the mapping results and review additional uses of the database created.

Jun 13, 2023

By D. R. Spears

The U.S. Bureau of Mines has developed a Fast Air-injected hydrocyclone-Shallow Tank (FAST) flotation system. Conventional flotation cell kinetics are a compromise between two conflicting requirements, the need for an agitated zone for rapid bubble-particle collision, and a quiescent zone for bubble-pulp separation. The Bureau of Mines has designed a flotation system in which bubble-particle collision and bubble separation are carried out in two discreet unit operations. A bubble slurry was mixed with an ore slurry at a high rate in a modified air-injected hydrocyclone for rapid bubble-particle collision. The mixture was then fed into a unit specially designed for rapid separation of the bubbles from the pulp. A conventional flotation cell required 2.8 min to obtain 90 pet recovery at a 7-pct Cu rougher concentrate grade, whereas the FAST flotation system can obtain 85 pet recovery with a 13-pct Cu rougher concentrate grade in 0.28 min, and 92 pet recovery with a 7-pet Cu grade in 0.56 min. The Bureau's FAST flotation system is adaptable to a wider variety of flow sheets and could potentially allow for replacement of conventional flotation cells with smaller and faster units.

Jan 1, 1991

"Longwall shearers are widely employed in underground coal mines. The reliability of such machine has significant importance for successful mining operations. This paper aims at studying reliability of a longwall shearer using failure data recorded for a year. Data was pre-processed, sorted and selected for analysis. Selected data is then examined using statistical models. Distribution fitting of time-between-failure (TBF) and time-to-repair (TTR) are accomplished using three different models. Goodness-of-fit criteria is used to ascertain the best fitting model. Reliability in terms of mean-time-between-failure (MTBF), and mean-time-to-repair (MTTR) are calculated using the model which best represents the failure data. Exponential distribution best represents the time between failure and lognormal distribution the time to repair data. A well-known risk management technique Failure Mode Effect and Criticality Analysis is used to evaluate the critical breakdowns. Critical system/parts, experiencing regular failures is delineated based on this analysis. INTRODUCTION Mining is a capital intensive process, and huge monetary investment is required to develop and operate a mining project. Heavy and expensive equipment’s are employed in development and operation of these projects. In order to ensure timely completion of set milestones, it is mandatory that equipment’s perform their required task productively. Delays are not unusual owing to breakdown of these equipment’s. Breakdown or failure experienced by any of the equipment pose heavy financial burden. Moreover, frequent times, companies have to employ and dedicate additional resources to make up for such delays. Delays in project is not only detrimental to company’s image in market, but it also interrupts customer commitments. Mines having history of not fulfilling their promise usually get lower commodity price. Penalties are also imposed on the companies defaulting its obligations. Especially, in today’s world where competition among the companies are growing, success means keeping up the commitments in a timely manner. Heavy machinery and equipment are instrumental in success of any project. These machinery and equipment’s have to reliable in a sense that they can perform the set task in given time period. Reliability of these equipment plays a pivotal role in success of any project. The reliability analysis of mining equipment has long history. Many researchers have applied different statistical models for analyzing the reliability of mining machines (Samanta, Sarkar [1]. Kumar and Klefsjö [2] demonstrated the use of the power law process model for reliability assessments of repairable mining machines. Barabady and Kumar [3] performed the reliability analysis from failure data of the crushing plants."

Jan 1, 2018

By T. Krumins, L. Zunti, R. Frischmuth

"Titanium and titanium alloys are commonly selected for pressure oxidation autoclave vent piping and pressure control valve components, as well as autoclave internals and other process piping. In the autoclave vent application, titanium ignition risk is controlled by limiting oxygen concentration, and preventing high gas velocity gas impingement on surfaces. Oxygen concentration is dependent on the autoclave pressure and temperature operating conditions and therefore oxygen concentration and the associated titanium ignition risk is dependent on standard operating procedures, process control interlocks and permissive conditions. It is not uncommon for these standard controls to be deficient during atypical operating conditions, or for operations to deviate from the operating procedures, increasing the potential for a titanium ignition incident. Titanium ignition risk caused by elevated oxygen concentration in autoclave vent systems can be reduced with the introduction of an online autoclave overpressure calculation and the configuration of associated interlocks and permissive conditions. INTRODUCTION High temperature pressure oxidation (>190°C) is a well recognized and versatile metallurgical oxidative pre-treatment process commonly used to liberate gold from refractory sulphide ores and concentrates before conventional leaching with cyanide. Titanium and titanium alloys are highly corrosion resistant in pressure oxidation process conditions and are therefore commonly selected as materials of construction for many components including: autoclave internals, agitators, process piping, and components in autoclave vent systems. Operations that anticipate or have experienced aggressive corrosion in the vent system often have little choice in material selection other than the use of titanium (Krag & Henson, 1992). Titanium is not suitable for use with elevated oxygen concentrations and is considered a restricted material because of its high pyrophoricity and combustion propagation properties (Beeson, Smith, Stewart, 2007). Several serious incidents have occurred in which titanium materials have ignited in autoclave applications (Zawierucha, McIllroy, Million, 1995). In autoclave vent applications, titanium ignition risk is reduced by preventing elevated oxygen concentrations, maintaining low gas velocities, and minimizing the potential for gas impingement on surfaces. Oxygen concentration in the autoclave vapour phase and vent system is dependent on the autoclave operating pressure and temperature conditions and therefore titanium ignition prevention controls typically include process interlocks and operating procedures based on the selected nominal design operating conditions. However, it is not uncommon for these controls to be deficient or for operations to deviate from the nominal operating conditions over time, increasing the risk of titanium ignition. The introduction of an online calculation of autoclave overpressure and a maximum target autoclave pressure as well as associated process control interlocks and permissive conditions can alert the autoclave control room operator and prevent an elevated oxygen concentration from developing, and therefore reduce titanium ignition risk in autoclave vent systems."

Jan 1, 2016

By D. Stone, R. Pakalnis, B. Seymour

Most mines using backfill routinely carry out quality control (QC) testing of backfill mixes with unconfined compression test cylinders. This is true for paste operations, hydraulic fill operations, and cemented rockfill operations worldwide. However, a large number of mines simply do not prepare and test the backfill samples in a consistent manner and fail to properly analyze or interpret the test results. Conventional concrete test criteria are not applicable given the differences in the mix constituents and the fact that a large number of the backfill QC test cylinders typically fail to achieve the target strength. Standard industry practices are needed to improve the analysis and interpretation of QC test results and to provide a better means of determining if the backfill is achieving its intended target strength. This paper will attempt to lay the groundwork for standard industry practices and will address several key questions raised by operators, such as how laboratory test data compares to in-stope performance, and how many QC tests should fail before a red flag should be raised. INTRODUCTION Although paste backfill is widely used throughout the mining industry, cemented rockfill (CRF) remains as the backfill of choice in places like Nevada where very poor ground conditions mandate the use of underhand mining. The safety and stability of undercut entries beneath backfill is a function of the quality of the cemented fill, which is typically assured through routine quality control testing. In the absence of a backfill quality standard, most mines rely on concrete standards to design and interpret their backfill quality control programs. In the USA, these standards are developed and published by organizations such as the American Society of Testing and Materials (ASTM) and the American Concrete Institute (ACI). However, the application of these standards to cemented backfills can be very difficult owing to the high degree of variability in backfill mixes and the resulting variability in test results. To illustrate, the concrete industry standards denote that an acceptable (passing) test result occurs when the average strength of the duplicate test cylinders exceeds the target strength and no single test result deviates from the target strength by more than 10% (ACI 214R). Remedial measures must be taken if three consecutive tests fail. With mine backfills, it is safe to say that these criteria are rarely achievable. A further, more dramatic example is the accepted coefficient of variation for concrete QC cylinders. According to ACI 214R, the coefficient of variation (CV) should range from below 3% (excellent rating) to above 6% (poor rating). However, if this analysis method is applied to several backfill QC databases from operating mines, coefficients of variation are calculated on the order of 50%. Clearly, there is a need to develop better industry practices for assessing the quality of mine backfill and to assist mine operators with the interpretation of test results and the development of action plans in the event of undesired outcomes.

Jan 1, 2019

By George E. Aikens

Prolonged subzero climatic conditions impose some unique engineering problems for the developer and operator of open-pit mines in the Far North. The remoteness of the job site and the extremely cold, long, dark winters severely tax both man and machine in the quest for the Arctic's rich mineral wealth. Undoubtedly the singular most troublesome problem for the engineer is Permafrost which underlies about 201o of the land area of the world and about 85% of the state of Alaska. Permafrost has its impact on building construction and mine excavation, while posing a more pervasive threat to the-delicate ecologic balance within the Arctic wilderness. Yet the difficulties associated with mining up North may not be as overwhelming as has been previously supposed. For example, the lowest temperature recorded at Point Barrow is -560F, whereas Montana has recorded -69.7° F.. There are no specially designed machines for mining and construction in the Arctic, and efficient equipment utilization is maintained through proper operation and servicing techniques. However, neither equipment or people can be assumed to function normally at -40°F. Special techniques in drilling, blasting, and ripping are being used to yield economically competitive ores. Overall, a fundamental understanding of the nature of Permafrost will allow the engineer to deal expeditiously with an Arctic mining venture and at the same time to deal fairly with Arctic environment.

Jan 1, 1972

By John W. Stevenson, Ted L. Sartain

Underground booster fan installations are currently employed in hundreds of coal mines throughout the world. Such installations, when properly designed and maintained, have proven to be safe and effective tools to provide desirable airflow volumes on sections or in areas of mines where the ventilation requirements exceed the capacity of the main fan system. In cases where an airshaft cannot be justified due to surface topography, depth of cover, or limited reserves a booster fan can serve the same purpose, be operational in a fraction of the time and at a substantially reduced cost. Booster fans are currently non-existent in U.S. coal mines. This is primarily due to lack of acceptance by the Mine Safety and Health Administration (MSHA), which has failed to acknowledge the merits of a booster fan system. Also, the absence of booster fan provisions in Part 75 of the federal regulations has led to the misconception that booster fans are legally prohibited in U.S. coal mines. In 1986, Jim Walter Resources, Inc. (JWR) developed and submitted to MSHA a plan to install and operate an underground booster fan at the No. 7 Mine. Detailed computer simulations were used to substantiate JWR1s position, that the booster fan could effectively provide the needed airflow on a developing section without adversely affecting ventilation in other areas of the mine. JWR also realized that numerous safeguards and operating procedures were essential for providing a safe system. Thus, safety features such as electrical interlocking, independent power supply, remote atmospheric monitoring, etc., were incorporated into the plan. This paper is a case-study that discusses JWR's proposed plan to install and operate an underground booster fan at No. 7 Mine. Unfortunately, MSHA's continued negative response has prevented implementation of the plan.

Jan 1, 1989

By M. Ruonala

The Larox Power PF Pressure Filter has been developed to meet the challenges of ever increasing output tonnages demanded by the minerals processing industry. This paper will highlight recent experiences at the Rudna Copper Concentrator in Poland, the Escondida Copper Concentrator in Chile and some large zinc concentrators in Australia. Detailed maintenance and operating cost information will be disclosed. Emphasis will be placed on economics on scale gained from higher machine throughputs.

Jan 1, 1998

By Benjamin Grunauer, Anthony Iannacchione, Taylor DaCanal

"In Pennsylvania’s rich mining history, various forms of room-and-pillar mining have been in use for over 150 years. Longwall mining, introduced in the late 1960s, occupies only the last 60 of those 150 years and now represents the dominant method of extracting coal in the Pittsburgh coalbed. The introduction of longwall mining allowed larger quantities of coal to be extracted in safer and more efficient manners than room-and-pillar mining. However, the associated formation of subsidence basins have elevated both the number and intensity of watersource and surface structure impacts. When these first longwall panels were mined the factors responsible for these impacts were poorly understood and regulations were focused only on surface structures. Today, with over 600 panels mined under a wide range of conditions, these factors are known and regulations have developed to help mitigate water supply and surface structure impacts.The cause and severity of surface effects are thought to be dependent on multiple factors, including the location within the subsidence basin, overburden, panel width, and orientation of the panel. The changing characteristics of over 600 longwall panels mined in the last 60 years are analyzed to determine factors important in subsidence related surface impacts. This study compares the location of the surface impacts with the longwall panel size, overburden, and maximum predicted vertical subsidence. The data shows that changing these characteristics are impacting surface features in a significant manner as measured by the number of company liable reported effects.INTRODUCTIONLongwall mining has occurred in Pennsylvania for over 60 years, and at the current mining rates, longwall mining is expected to continue in the Pennsylvania Pittsburgh Coalbed until the reserves are exhausted. Figure 1 shows all mining that has occurred in the Pittsburgh Coalbed, as well as the area that is left to mine. It is predicted that there are 40 years left of longwall mining on the Pittsburgh Coalbed, under the assumption that 50% of the total 280,000 acres will be mined at the current rate of 3500 acres/year."

Jan 1, 2019

By J. D. Crone

Crone Geophysics Limited in co-operation with Newmont Exploration Limited has developed a ground Pulse electromagnetic method. This is the first unit in a planned integrated system of surface and borehole Pulse EM equipment. Newmont had previously developed an operational Pulse EM unit for use in areas of very high surface conductivity. The Newmont equipment was large, heavy apparatus that required motorized transport. It operated in the equivalent frequency spectrum of 10Hz to 2.5Hz. The basic aim of Crone Geophysics was to design a Pulse EM system more portable than Newmont's. We wanted to operate in all types of field conditions including heavily wooded and mountainous terrain areas. We also wanted to record the higher frequency information that is contained in the Pulse EM waveform. There are three reasons why we thought this high frequency information was important in survey applications: (1) Field tests conducted over massive sulphide bodies in the Arizona desert showed that the desert weathering process tended to break down the electrical contact between sulphide crystals. The net effect is to reduce the conductivity of a massive sulphide body, particularly narrow bodies or highly fractured sulphide zones. In order to detect such occurances the higher frequency information is essential. (2) We wanted to be able to detect occurances with sulphide content as low as 5% sulphides that are usually poor to moderate conductors. (3) We also wanted to be able to determine the presence and extent of surficial conductive formations and clay deposits since many airborne EM anomalies are caused by such bodies. If we have the capability of detecting and recognizing these formations we would be able to explain the airborne anomaly.

Jan 1, 1976

By K. F. Unrug

The identification of the major subsidence areas in the Western Kentucky Coal Field has been made to distinguish the subsidence phenomena on the basis of geographical location Further, this identification process is based upon selected critical geological, topographical, and mining features in the coal fields. The proposed identification of the regions is derived from a comparison of the subsidence potential in a particular area. The most likely severe subsidence areas are compared to those with the probable low subsidence severity. The combination of certain geological and mining parameters involved allows for the derivation of a classification of the subsidence potential. It is recommended that further site specific studies should be performed on this area.

Jan 1, 1986