Search Documents

By J. Sidhom, W. Fourie

"As the mining industry continues to face difficult challenges the need to persistently focus on productivity and utilization of labor and equipment costs will intensify. With these challenges in mind, Joy Global is helping to bring mining performance and analytics to the next level. By evaluating underground haulage, a significant component of the Room and Pillar mining value stream, variables have been identified and sensitivities have been performed to show opportunities to balance and streamline throughput. As a result of applying operational excellence tools to the mining environment, Joy Global is seeking to optimize mining performances by limiting waste, simplifying the process, increasing productivity and machine utilization, as well as removing workers from harm’s way. These days it’s not enough to work harder; mines have to work smarter. Improving efficiency, reducing costs, increasing safety: these are no longer ‘nice to haves’, they are ‘must haves’. Starting with the best products and the right people is a first step, but then what? How do mines take their operations from just OK to being a top performer? By using operational excellence principles aimed at eliminating waste, simplifying processes, automating where possible and removing people from harm’s way. The fundamentals of operational excellence (OpEx) are based upon the DMAIC process, which stands for define, measure, analyze, improve and control. DMAIC is an improvement cycle that helps with, for example, haulage optimization by: defining the issues and problems in the process as well as the areas of improvement; measuring and collecting mining operational data by time study and equipment monitoring system; analyzing through sensitivities and production modelling to determine root causes; then improving the performance and controlling the operation. Joy Global uses Joy OpEx or ‘lean’ principles inside its organization to drive efficiency, but it also helps its customers employ them to achieve new levels of productivity and safety. These same principles can be applied in most situations to streamline processes, improve operations and deliver value. As applied to mining, OpEx is seen as moving the needle on value creation by first identifying the value stream, then analyzing the areas that are not optimized. Once defined, these areas are ‘designed out’ of operational processes to create an automated operational flow. At a US coal mine, Joy Global was brought in to apply Joy OpEx principles to optimize mining and haulage to improve productivity and reduce costs. This multi-phase process started by defining the existing systems challenges to start finding areas for improvement."

Jan 1, 2017

By Dragomir Gospodinov, Savka Dineva

A surprisingly large mining-induced seismic event occurred in the LKAB Kiirunavaara Mine (Sweden) on 18 May, 2020 at 03:11 (local time). The estimated moment magnitude was 4.2. The event caused extensive damage in a large section of the mine. The production in the area is not yet resumed, even by the beginning of 2022 (~20 months after the event). The Kiirunavaara Mine has one of the world’s largest underground seismic systems with approximately 253 geophones. The in-mine records of the event showed a very complex character with a several sub-events. The event was also well recorded by seismic stations out to over 9,000 km distance. Data from the underground and regional seismic systems were analysed to define and compare basic source parameters such as hypocenter location, seismic moment, as well as the seismic moment tensor. The data from the in-mine seismic system was used to study the development of the seismic process and to define elementary seismic sub-sources together with the official hypocenter location.

Apr 26, 2022

By R. R. Hall

Tests were conducted to assess the potential of column flotation for beneficiation of a talc ore from Montana. This ere contained approximately 80% talc, with the gangue comprised mainly of chlorite, silica, and dolomite. A tributylamine, MIBC, and sodium silicate reagent suite proved effective for talc flotation. Rougher-cleaner column flotation in a continuous open-circuit produced a final talc concentrate which contained 0.90% Al2O3. 0.17% CaO, and 1.28% Fe2O3. These analyses represented impurity rejections of 77, 85, and 65%, respectively. Weight recovery for this open-circuit was 52%; however, weight recovery was estimated to be 75% with cleaner tailings recycle. Results from this investigation show that column flotation is a viable means for beneficiating talc.

Jan 1, 1990

By Mogens Henriksen

In the past decade, numerous urge scale drilling projects have made use of reverse circulation air lift methods. Reverse air lift pumping can be established by injecting gas into a column of liquid; the subsequently decreased density of the gas-liquid mixture allows atmospheric pressure outside the lift conduit to establish flow. The rate of flow can be controlled by varying the gas to liquid ratio. A typical reverse circulation air lift system is depicted in Figure 1. Allen1 has described a number of reverse air lift drilling projects. Although cited examples are generally related to large diameter holes, the method has seen use in other applications such as sand dredging, chemical pumping, water well pumping and continuous coring. One particular benefit obtained with enclosed reverse circulation drilling is elimination of lost circulation. The required air/water ratio for pumping at a given submergence and lift has been established experimentally by Gibbs2. His data, however, do not reflect sensitivity of flowrate to air/water ratio. Further, in Gibbs' work, air apparently is injected continuously along the column of water. This configuration differs from that used in reverse air lift drilling where air is injected at discrete points only. Gas lift theory has received considerable attention over the past decades. Orldszewski3 defined flow regimes in two phase flow. Griffith and Wallis4 determined relative velocities of gas to liquid. Two-phase flow has been studied extensively for oil transport in inclined and vertical pipes by Chierici et a15, Beggs and Brill6, and Gould, Tek and Katz.7

Jan 1, 1977

By L. Kulik

Sustainability of lignite mining in the Rhenish lignite mining area is ensured by a preceding study of the overall project, with the involvement of all those affected. The supporting holistic consideration of the various sustainability elements is essential for a later balancing of the several ecological, economic and social concerns. In what follows, a brief overview of the Rhenish lignite mining area is given as introduction to the focus of this report, which is on sustainability, starting with the approval procedure under regional planning law incl. opencast mine planning, and extending to concrete on-the-spot implementation, taking the Garzweiler II follow-up mine as example. To illustrate the issues involved, an account is given of some selected sustainability elements.

Jan 1, 2005

By Joseph Peterson, Alexander May

The Bureau of Mines used geochemical modelling computer programs to characterize a site containing lead slag generated by a lead processing facility. Tests for toxic elements by the U. S. Environmental Protection Agency (EPA) extraction procedure showed that all elements except lead were in compliance. Concentrations for lead ranged from 28 to 30 ppm. However, analysis of water samples from monitoring wells resulted in no lead concentrations that exceeded the National Drinking Water Standard. A discussion of a computational program to calculate concentrations of lead species and several other ions is presented.

Jan 1, 1991

By M. C. Fuerstenau

Flotation data indicate that sulfonate and dodecylamine adsorb physically on Mn02 at ambient temperature. Oleate also adsorbs physically if the zero-point-of-charge of the Mn02 is sufficiently high. Chemisorption of oleate apparently occurs between pH 8 and 9, and this phenomenon is enhanced considerably at elevated temperature.

Jan 1, 1966

By R. P. Aldis

A wide range of mineral-derived products are required by the electronics industry for it to function. In one form or another, almost all the known elements have been experimented with and tested for various electrical applications. The two major areas for which minerals are used in electronics are as conductors and semiconductors. Conductors provide the means to transport and distribute electricity, while the main application of semiconductors has been to manipulate electricity. Silicon is the most widely recognized semiconductor material, but gallium, indium, and germanium are rated as the most important metals to the semiconductor industry for future and near future technologies.

Jan 1, 1991

By Rambabu Pothina, MELO EDUARDO PIMENTA DE, Rajive Ganguli

 The mining industry is home to a mass of sensor-generated data that are critical to real-time and long-term optimization. This heavy reliance on sensor data has resulted in an undesirable development. The industry is reluctant to verify the accuracy of sensors as it would mean shutting down important processes. Sensors are typically calibrated once a year, if at all. Errors in sensors go undetected until the next calibration or until errors are so gross as to be obvious

By A. L. Wilder

Coeur d'Alene Mines Corporation's newest precious metals property is located in the old Rochester Mining District approximately twenty-five miles northeast of Lovelock, Nevada. Built at an elevation in excess of 6 000 feet, the Coeur-Rochester gold silver heap leach property encountered cold weather operational problems typical of most northern Nevada heap leach properties, soon after the start-up of operations last fall. Due to the size of the heap area under leach at Rochester, it was decided that 1 the usual practice of spraying to an "ice field" and waiting for the spring thaw was impractical. Further, the delivery schedule for a solution heating system of the size required was unacceptable. Accordingly, Rochester personnel embarked on a program to seek out a leach solution distribution system that would enable an operation through the winter and yet be cost effective. The findings of this program were rather dramatic and, as a result, the whole perception of heap leach solution application at Rochester has changed forever.

Jan 1, 1988

By D. Brandt

The Dos Pobres Mine is a copper oxide heap-leach operation located near Safford, AZ. Mine production is 163 kt/d (180,000 stpd) with a stripping ratio of 2:1. During the startup phase of the mine, the required fragmentation size was easy to achieve as the ore was highly weathered and fractured near the surface. As the mine depth increased, the proper fragmentation size became harder to achieve due to less weathering and different rock types. Because copper recovery increases as crusher product size decreases, achieving the appropriate product size at the crusher is the operating priority. The engineering department began a project to improve fragmentation through blasting and thus increase throughput in the crushing system. It soon became clear that input from other departments was going to be required to make this a safe and economical project. Therefore, the crush and convey and ore control departments worked together to evaluate all available data on blast patterns and explosive loads and tracked performance and results. Using image analysis, drill energy index and databases, improved fragmentation size has been achieved and results have been verified while controlling costs.

Jan 1, 2011

By S. Shi, J. Y. Hwang, B. Li

Silver, copper, and zinc are commonly known elements with antibacterial and antifungal capabilities. Attempts have been made to dope silver on minerals, glass, and ceramics and the resulting materials have been investigated for their antibacterial and antifungal properties. Since silver is expensive and very reactive, silver doped materials have been found inappropriate in some applications. Copper-vermiculite is investigated as an alternative. Vermiculite has high cation exchange capacity on the magnesium ion in the crystal structure. Copper ion may have a high tendency to replace magnesium because of similar charge interference and ionic radius. Copper-vermiculite is prepared by reacting vermiculite and copper chloride solution. By impregnating copper ions into the nanometer openings between the layers of vermiculite, it is possible to render the composite with antibacterial functions if the copper ions could be released gradually from the composite. The antibacterial efficiency of Cu-vermiculite against Escherichia coli was studied using the Halo method. The results show that Cu-vermiculite is effective for preventing the reproduction of the bacteria. Heat treatment of Cu-vermiculite at up to 400°C does not show significant changes in antibacterial activities.

Jan 1, 2002

By Carla L. Zenti

In recent years, considerable advances have taken place worldwide in the design and construction of first tunnel linings. With these advances, there is a tendency to move away from traditional support that includes heavy open profiles of rolled steel arches, to a lighter solution with the use of an optimized tubular steel cross section rib, and shotcrete reinforced with steel mesh and/or steel fibers, providing a continuous support (Lunardi, 1982). The development of tubular ribs has provided greater design options, increasing flexibility to engineers and contractors while providing a efficient and cost effective construction method. In this article, the authors describe numerical and experimental investigation on this problem, suggesting as a new first lining steel arch design approach by using tubular ribs cross section as new technical solution for first lining underground support.

Jan 1, 2012

By J. Kemeny, J. Lyons-Baral

"Point cloud technology is now an indispensable tool in geological and geotechnical data collection, interpretation and analysis. Open pit and underground mines of all sizes are regularly collecting point cloud data as Laser Scanning (LiDAR) and Photogrammetry surveying devices have finally become affordable and the workflows fast and efficient. Past challenges of large data processing and manipulation are gone with recent technological advancements in computer hardware and software. These innovations reduce file sizes, ease rendering requirements and allow for the implementation of real-time 3D viewers and surface meshing tools. With its ability to remotely (safely), rapidly and accurately extract large quantities of georeferenced and 3D-oriented data, point cloud technology provides numerous applications to the geomechanical field. The list of uses is continuously growing, so this paper specifically focuses on digital outcrop modeling and digital terrain engineering. INTRODUCTION Point Clouds The high-resolution and increasing availability of point cloud technology is rapidly improving open pit and underground mines’ investigation, interpretation and characterization of site geology and rock mass properties (Kemeny et al., 2015; Lyons-Baral, 2012). LiDAR and photogrammetry are common remote sensing methods employed to measure the coordinates of surfaces in three dimensions (3D), providing the X, Y and Z locations, and typically the reflective intensity and/or the visible three-band color of each point (Figure 1). LiDAR uses either a time-of-flight or phase-shift measurement of a laser beam reflected off targeted surfaces and received back into the device. Photogrammetry generates point clouds by merging multiple overlapping photographs and uses stereographic plotting to define the locations of object points in 3-D space. These methods can be deployed from airplanes, unpiloted aerial systems (UAS or drones), tripods, land vehicles, and even in a mobile backpack shown in Figure 2. RADAR, Total Station-Prism and other remote sensing systems also offer very precise “point clouds”, but this paper does not address these due to their higher cost and lower versatility and mobility. Technology In the past few years point cloud acquisition device prices have dropped significantly, devices have become lighter, smaller and easier to operate, and processing and utilizing the data has also become faster and easier. Device size improvements include mobile backpacks (Figure 2) and handheld mobile LiDAR (CISRO, 2014), allowing mobile scanning in tight spaces both above and below ground or inside and outside of man-made structures. Airborne data acquisition options have expanded dramatically with the spread of UAS technology as seen in Figure 3 (Hexagon Geosystems, 2015). Once UAS usage regulations are sorted out, these versatile machines will be everywhere, offering high resolution coordinate scans, imagery and other remote sensing. While backpacks and handhelds allow access to tight quarters, UAS permit rapid data capture from narrow to broad areas with multiple perspectives reducing data “shadows.”"

Jan 1, 2016

By Poltak Sinaga

PT Kaltim Prima Coal?s 13-km (8-mile) overland conveyor (OLC) was commissioned in 1991. It is a conventional three-roller, 35 degree trough belt type. Cost and performance optimization during initial design resulted in a 5.4-m/sec (17.7-ft/sec) belt speed, 1,000 mm- (40 in.-) belt width to convey 1.35 kt/h (1,490 stph) and 7 Mt/a (7.7 million stpy) of coal. Despite a high initial figure, the belt speed was lifted to 6.5 m/sec (21 ft/sec) in 1996 to accommodate mine throughput in-crease. In 2002, a new low loss ST2100 1,100 mm- (43 in.-) wide belt replaced the ST2250 that was due to be changed-out. An upgrade project was initiated at the end of 2003 to further increase the belt speed to increase the OLC capacity to 30 Mt/a (33 million stpy). Upgrading the OLC by increasing the belt speed was the lowest capital option. Increasing belt width and/or modifying the trough angle to have larger cross sectional area was not an economical option because it would require expensive changes and significant down time of the OLC. To achieve 30 Mt/a (33 million stpy), the belt speed had to be increased to 8.5 m/sec (28 ft/sec). Although such high belt speed looked feasible, there was no information at that time of other OLC operating at such high speed. There was a risk that the conveyor would not operate safely and reliably at higher speeds. This risk was escalated by the fact there was no facility to lower or fine-tune the belt speed once the higher belt speed was implemented.

Jan 1, 2009

By E. Farrokh

CSM and NTNU models are among the most commonly used models in TBM performance evaluation. Due to increasing application of TBM in different tunneling conditions, modification became necessary for these models. Sensitivity analyses on these two models indicate that both models are very sensitive to machine characteristics. Analyses performed on CSM database for cutter load and penetration rate prediction indicate while the r-square of the CSM model is reasonably high for the predicted cutterload, the r-square value for the penetration is low. In order to increase prediction capability of CSM model for penetration rate the model was reevaluated using non-dimensional analysis and the original database of Colorado school of mines. NTNU model is evaluated using Monte Carlo simulation and regression analysis. The results of analyses indicate that the majority of the variation of the penetration in NTNU model can be explained by only three parameters. This might indicate that the effects of other factors are overshadowed and it is worthy to reevaluate NTNU model using original database and more updated statistical methods to avoid overlapping of different parameters correlations.

Feb 23, 2014

By Frederick B. Henderson

On 10 August 1976, The Geosat Committee was organized in Denver to institute The Geosat Program. This program is an industry backed effort to evaluate and help select optimum space remote sensing systems for geological purposes. It is believed that the recommendations of The Geosat Committee can be supported by industry as additional exploration tools which can materially benefit industry and the Nation with respect to our energy and other natural resources needs. Appended is a general summary of The Geosat Committee Organizational Meeting and general review of The Geosat Program. The Geosat Workshop Report. The Geosat Committee, and The Geosat Program will be reviewed at a special afternoon session, Friday, 3 September.

Jan 1, 1976

By Troy Holm, Matthew L. Fuller, Frederick H. Earnest

Virtual Reality Animation Of The Proposed El Dorado Mine In El Salvador Assists Regulators In Reviewing An EIA

Jan 1, 2005

By Masaji Kato, Yuusaku Tominaga

To maintain good condition of ventilation for both safety and economy, many regulators are installed in a network. In case the open state of a regulator is different from the set point, identification of a broken regulator and a countermeasure to recover airflow distribution in a network must be initiated as soon as possible. An experienced mining engineer can sense a deviation from ordinary airflow quantity. In this paper, a new system to monitor all the regulators in a network is introduced. The basic concept of the system is utilization of both human sensing of airflow rate and computer simulation to understand the macroscopic characteristics of a ventilation network. A fuzzy pattern distinction method is used to process human determination of airflow rate that may be ambiguous. The applicability of the system is demonstrated using the ventilation network of the Horonai coal mine, Japan. In particular, it is shown that the system can identify the regulator to be repaired from information supplied by workers relating to air- flow in a few sensor branches.

Jan 1, 1997

By I. Yildirim

Free energy of interaction between particles in water can be calculated if one knows the values of appropriate interfacial tensions, which in turn can be determined from the surface free energies of the particles involved. The latter can be determined using the Van Oss-Chaudhury-Good (OCG) equation. This method requires the measurement of contact angles of well-defined liquids on the surfaces of the particles of interest. In the present work, the contact angles were determined using heat of wetting, capillary rise, and thin-layer wicking methods. The results are compared, and the utility of the surface free energy data obtained from the contact angles are discussed.

Jan 1, 2002