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By D T. Froedge

The latest development in vibration measurement equipment involves small microcomputer operated micro-sized seismographs. As the result of this there has been an explosion of the data generated by these systems. For example: ten micro-seismographs taking ten shots generate over 2.5 megabytes of data.

Jan 1, 1994

By Shahid Islam, Lucian Bogdan

There is a rapid expansion of world’s infrastructure and simultaneously existing infrastructure is aging. The maintenance of infrastructures has been of particular concern to the engineering community. Monitoring and evaluating the structures have become more significant than ever. Ground anchor is an important part of the structure where it is installed. Unfortunately there are limited testing methods available to assess the force in the pre-stressing steel. High cost, complicated equipment and limitation of space often prevent these methods from being implemented. DYNA Force sensors have been developed to measure the force in the pre-stressing steel during construction and at any time during the lifetime of the structure. These sensors make use of the magneto-elastic properties of ferrous materials. A readout unit is designed to magnetically energize the steel through the sensor and measure the response of the steel to the process. The readout unit then converts the response into a direct force reading. They can be used for bare, epoxy- coated, galvanized and greased-sheathed steel in the bonded, un-bonded, grouted or un-grouted length of the tendon. It measures the force of the steel element at the location where it is installed and can be recorded manually, automatically, or remotely. The sensor is robust, requires no maintenance and it is expected to have a similar service life to that of the surrounding structure. Sensors have received attention in terms of accuracy, performance, ease in installation, durability, and cost effectiveness. Sensor readings provide a second measurement, in conjunction with the jack pressure gauge, of the post tensioning force during initial testing procedure for ground anchors. This paper describes its application in tie-back and tie-down anchors and force monitoring of retaining walls, bridge abutment and dams where the data were collected manually, automated and remotely. INTRODUCTION Our infrastructure is expanding and the existing infrastructure is aging. Some structures are expensive to maintain and some occasionally fail. There is a large demand for implementing health monitoring of structures. Many tie-backs, retaining walls, dams and other geotechnical structures are post-tensioned and many of them need repair using a post-tensioned system. On many occasions during construction and service life of the structure, it is useful to know the force in the post-tensioning and anchor system. Many piles and drilled shafts are designed using reinforcing steel and the compressive forces in reinforcement are unknown. Although there are many methods to measure the tendon force, most of them are cumbersome, expensive, and the accuracy varies depending on the method used.

Jan 1, 2018

By Michael J. Kelly

IAMGOLD?s Westwood project is the site for the largest, by volume, bored vent raise in North America. When completed, it will be the fifth largest bored worldwide in a single pass. This paper will review the highest capacity raise drill system ever built (Redbore 100); as well as the technical difficulties in a single pass boring a 2,773 ft x 20 ft to 22 ft diameter raise. The difficult ground conditions and associated problems will be reviewed, as well as the solutions to overcome them. Use of the RVDS drilling tool to achieve .04% accuracy (14.5?) and the Geotube® water filtration system will also be covered.

Oct 1, 2010

Mineral Resource Technologies(MRT) and Michigan Technological University (MTU)finalized an agreement that permits MRT to offer an advanced carbon removal technology process for coal fly ash from an ash residue generated by utilities. The agreement encompasses the dominant existing US patents using a wet process for fly ash enhancement. The wet process for coal beneficiation of a fly ash product involves four steps. First, a slurry mixture is formed of a fly ash material and a liquid. Second, gravity is used to separate and collect a first-material fraction of the fly ash, having a density less than the liquid. This is done by skimming off the flotation slurry material.

Jan 1, 1996

By József Faitli, Barnabás Csoke, Károly Solymár, Zoltán Hatvani, Dimitri Papanastassiou

In most cases, the sizing of dry or wet mills for ore processing is primarily based on the determination of the Bond grindability index, using the Bond-Kjos-Rowland relations. In several cases, grinding takes place under conditions different from these and the grinding conditions have a great influence on the postgrinding process. This is particularly true for the grinding of bauxites where grinding takes place in alkali, often in higher temperature in alkali Liquor. So it is necessary to develop a testing method providing a reliable grindability index even under these special circumstances and allowing a more precise mill sizing. Therefore we surrounded the grinding crucible of the Hardgrove mill with a crucible furnace to heat it. The new heated mill is suitable to determine the grindability index under temperature-controlled circumstances, in liquids (water and alkali) with different temperatures. The required heating power is 2000 W. In the implemented equipment we installed four 230V/500W electric heating wires made from heat-resistant alloyed material and surrounded by ceramic insulators. The temperature and temperature-gradient are measured by four PT100 platinum thermal resistors. The data acquisition and control program written in the C language in the Lab Windows CVI program environment measures the voltage proportional to the temperature. Determining the grindability indices of hungarian and greek bauxites experimentally, first dry grinding tests were carried out under standard conditions. During wet and alkaline grinding, to 50 g of dry bauxite 85.5 g of industrial alkali with a concentration of about 200 g/l was added. As grinding aid 2 g of CaO (4 % of dry bauxite) was dosed. From the data it can be concluded: - The tested bauxites show a similar behaviour against temperature change. However, the extent of grindability change is different for different bauxites. - Soft Hungarian boehmitic bauxite can be ground in a high-temperature alkaline medium better than hard Greek one. The increase of grindability according to the high-temperature Hardgrove indices: (kHT = Dry o HT,alkaline H /H ): for hard Greek and soft Hungarian boehmitic bauxites: kHT = 1.7 and 2.4 respectively; according to estimated Bond indices (kB,HT =Wi,dry/Wi,HT, alkaline ): kB,HT = 1.6 and 2.1. - The increase of grindability is the most important factor the reaction of kaolinite with caustic liquor and lime and the loosing of the textural structure at 80 ºC and especially at 100 ºC.

Jan 1, 2003

By F. Dahl, P. Raleigh, J. Holzhauser, B. Nilsen

Tunnel excavation using tunnel boring machines (TBMs), has become increasingly common in recent years, despite the fact that precise evaluation of certain risks have not kept pace with the use of these machines. One of the risks easily overlooked by Engineer and Contractor alike are the effects of abrasive ground on the costs and schedule of a given project. The impacts of worn and damaged TBM cutter heads have been observed on hundreds of tunnel projects around the world. It would appear that a reliable prognosis of the abrasiveness of soils on a project would be of great importance for designers, clients and contractors alike. Several well acknowledged test and prognosis methods already exist for rock, however there is only very limited knowledge available to describe the abrasiveness of soil and its impact on soft ground TBMs. This paper will examine approaches to this problem and suggest a new approach based on a current project undergoing design.

Jan 1, 2007

By Carl Sunderman, Steve Signer

Researchers at the National Institute for Occupational Safety and Health (NIOSH) have developed several new tools for evaluating roof support performance. A miniature data acquisition system (MIDAS) was developed that can collect readings from up to 16 strain gauges at regular time intervals and store the readings for later retrieval. Three LED lights change from green to yellow, then red, based on the reading levels and/or rates of change of rock movement. This feature can be used to warn miners of rock instabilities. The system can be used with any strain-gauged support (resin bolt, friction bolt, cable bolt) or with a newly developed rock strain strip (ROSS) developed by NIOSH to measure rock strain. A ROSS is grouted in a hole drilled adjacent to the rock support to be evaluated; the deformed shape of the ROSS provides anchorage on either side of the strain gauges. Data from both laboratory tests and field evaluations are presented that describe the capabilities of both the MIDAS and ROSS instruments.

By Philip Thompson

Many new evaluation tools have been developed since the early 1990’s to aid the minerals processing test engineer. The areas of comminution, gravity concentration, flotation, and process mineralogy have received particular attention. This paper will describe new laboratory procedures in the areas of SAG mill testing, gravity concentration, and flotation testing. Computer assisted mineralogical examination equipment, new generations of mass balancing programs, and simulation programs will also be discussed.

Sep 12, 2005

The compliance sampling method for coal mine dust in the United States has not changed appreciably in the last 30 years. A call for more frequent sampling with immediately available results is leading to new instruments that may supplement or replace the existing sampler. This report discusses two such instruments that provide immediate results of dust levels. The first, called the Respirable Dust Dosimeter (RDD), is designed to supplement the existing U. S. cyclone compliance sampling method. It uses the pressure drop across a filter to provide an inexpensive screening type of measurement. The RDD has been tested in the laboratory and a limited number of coal mines. Side by side testing has compared the RDD performance with personal coal mine samplers in triplicate area sample measurements. Results show that the differential pressure of specific filtration media can be an effective surrogate for respirable mass. Data show that there is a dependence on coal type and an effect of relative humidity. There also appear to be two distinct responses related to coal type. For specific coals the coefficients of determination, R2, are better than 0.9. For general use the detector tube, using laboratory generated calibration curves, can be used to estimate respirable dust levels. However, a calibration to a specific coal type may substantially improve the accuracy. Another sampler in development is called the Personal Dust Monitor (PDM). Designed to give compliance quality accuracy, the PDM uses the frequency change of a vibrating element to measure dust and give immediate feedback of results. Results of laboratory comparison of the prototype PDM sampler to personal gravimetric samplers indicate R2 values of better than 0.99 for three different coal types. Work is in progress to package the components into a person-wearable unit combined with a cap lamp system with a total projected weight of less than 1.4 kg (3 lbs).

By Roger Scarr, Richard A. Walker

Interactive video is the combination of computer and laser disc -technologies that allows for the storing of 54,000 single images or 30 minutes of video with the ability to access any segment or single image within a half a second. This capability combined with the use of a graphics overlay on the video and accessed through a keyboard or touchscreen creates a very powerful and versatile marketing or training tool.

Jan 1, 1990

By K. Halada

Current trend of the global flow of strategic metals are analyzed to discuss the strategy of the development of recycling technology and alternative technology. In many cases, each global flow of metal is changing from the trilateral structure of U.S., EU and Japan in the later 20th century into the convergence to China as the factory of the world. Scrap flows are also changing dynamically. A long term change of prices of metal has gotten changed since the entrance of this century. The estimation of metal consumption up to 2050, in which the author estimated that many kinds of metal will overshoot the reserve base line, is revised considering these change of current trends.

Jan 1, 2014

By K. Short

Over the past several years, the mining and minerals market was overloaded with discussions around reviving mature terminologies like distributed control systems (DCS), programmable logic controllers (PLC), and the ?new comers?: hybrid control systems (HCS) and programmable automation controllers (PAC) and, in parallel, which technologies would be more appropriate for mining and mineral processing applications. Ten years ago, a careful comparative analysis would make more sense. Control approaches had very distinctive differences where users needed to choose the right approach.

Jan 1, 2012

By R. Kaushik

According to the U.S Department of Energy (DOE), mineral processing activities including comminution (size reduction) uses 4% of the world electrical energy consumption. Such numbers reinforce the need to invest in energy savings initiatives in order to produce more using less. ENERGY EFFICIENCY OPPORTUNITIES AND CHALLENGES IN MINING OPERATIONS In addition, DOE, in its Mining Industry Energy Bandwidth Study, has identified huge potential for energy savings for the coal, metals and mineral industries. Even knowing the overall causes of energy waste and some potential tools for remediation, mining companies may struggle to apply such tools and get the desired results due to the following reasons: ? Limited staff ? Lack of accurate economic and investment analysis to justify energy savings projects ? Lack of knowledge to identify low or no-cost savings opportunities ? Internal competition for resources According to the workforce and talent management experts, the Talent Strategy Advisors, the demand for mining engineers is expected to exceed supply by 30% by 2013. Mining personnel are likely to be burdened with increasing and varied workloads with limited training. This will result in the need for automated and simple tools to support energy efficiency activities. Mining engineers will simply not have the time and resources to create such tools, collect and analyze the data to make decisions, and track results.

Feb 27, 2013

By J. Kunze, R. Degal

During the last 100 years, the submerged arc furnace has been one of the most amazing diversified melting units. These furnaces have found their application in more than 20 different main industrial areas such as iron, ferro alloy, chemical industry, lead, zinc, copper, refractory, titanium oxide, recycling, phosphorus etc. Such an evolution was only possible because of tremendous efforts in research and development and due to the large range of design solutions. The worldwide strong competition also forced the industry and plant suppliers to develop highly efficient, economically balanced units in optimized sizes and with long lifetimes, to adapt to the market conditions. Regarding the environment, the plants improved significantly in terms of water treatment plants and off-gas treatments as well as on site recycling units. This paper will give a short overview regarding the history of the furnace and the latest developments in today?s main application fields: ferro alloys, non-ferrous, special application and recycling. In addition new activities in research and developments are briefly discussed.

Jan 1, 2004

By M. Tanaka, S. Kita, Y. Jinnouchi, Y. Sawada

This paper generalizes the results of the recent theoretical and experimental investigations on the air-pulsated jigs in Japan. The pulsating mechanism is analyzed as a special vibratory system, and the jigging mechanism as a mass system subjected to the law of hindered settling. The results of investigations on the following items are reviewed: dynamics of the pulsating mechanism; pulsation in a practical TACUB jig development of a new type of air valve; uniform pulsation in a large Baum jig; motion and mobility of bed particles; separating speed in hindered conditions; and standard deviation in practical jigs.

Jan 1, 1985

By Raymond C. Voige

"The use of current electronic technology in the design of new underground mine communications equipment is providing improved and expanded voice communications which can, in turn, contribute to improved productivity and safety. A review of equipment that is now available or under development Includes the following categories:WIRED SYSTEMSI.Pager phones with selective calling, audible and visual alerting and message indicator.2. Mufti-conversation pager phones that use multiwire cable ormultiplexing techniques.WIRELESS SYSTEMSLow-and medium-frequency inductive systems utilizing ""near"" magnetic fields for both vehicular and personal communications.Wired SystemsCommunication systems in underground mines have evolved slowly in many parts of the world. For many years, magnetotype telephones were the only means of communication from one mine level to another and to the surface. These units were located near the shaft and communications to the working areas were limited."

Jan 1, 1981

By F. Mielli

Camera systems and video surveillance are usually associated with people and asset protection. However, they can be applied in a mine environment beyond conventional surveillance: For process monitoring, collision avoidance, sizing, flotation cells, conveying systems, blasting, objects and people tracking, thermal profile, and to automatically identify equipment that is missing parts,. Image and video solutions can be driven by better integration of powerful video analytics and cameras systems in automation tools such as process controllers and supervision systems.

Feb 27, 2013

By J. H. Archibald

"In mines employing cut-and-fill stoping (sand fill), ore passes are built as mining progresses upward. These ore pass raises are generally made from timber and form a vertical ""chimney"", like a very tall log cabin. Traditionally the chimney, or raise, is square in shape and is constructed from square timbers with stepped ends as shown in Figure I. The timbered raise is thus surrounded by sandfill on its outside, leaving the centre open for passing ore down through it. Each layer consists of four timbers and rests flush on the layer below. The corners are frequently pinned or spiked.Under certain conditions in sandfilled stopes large horizontal loads may be transmined to the raise cribbing timbers, or the ""chimney's"" walls. In deep mines, where rock bursts are a problem, it can be shown that one of the conditions for rockbursts to occur is that the burst zone be stiffer and weaker than the surrounding rock(l). This allows a strain energy build-Up in the rock surrounding the burst zone, and the rate of release of this strain energy is known to be related directly to the over-all strength and stiffness of the rock in the burst zone. In stopes that are sandfilled, attempts are, therefore, usually made to increase the strength of the sandfill by the addition of large-sized waste rock and Portland cement. These measures usually achieve the desired strength of the sandfill and, consequently, the severity and frequency of rockbursts can be reduced.Problems may arise when the now chunky sandfill transmits high loads to the raise cribbing along with relatively large move- merits. This leads to heavily stressed and strained cribbing timbers the Coeur d'Alene district in Idaho, raise cribbing failures are common. A typical mode of cribbing failure is shown in Figure 2. One learns in statics that a structure shaped like the crib in Figure I is inherently unstable , at least from a structural standpoint. The crib has pivoted, in Figure 2, into a rhombi c shape and supports very little load. Soon the four-foot square raise cribbing made from 5 in. by 5 in. timbers will no longer pass ore."

Jan 1, 1991

By B. G. White

Traditional interpretations of vein ore deposits in the Coeur d' Alene Mining District, such as the view that these deposits formed in a transcurrent tectonic regime during the Precambrian, are being supplanted by the view that the deposits (1) formed in low-grade metamorphic shear zones similar to those that host an important type of gold deposit, (2) display features, such as wall rock carbonate zoning and vein zoning, that are common to ore deposits elsewhere, and (3) are probably Mesozoic and possibly related to emplacement of the Idaho batholith. In recent years, new interpretations have led to major ore discoveries that are likely to extend the life of the district for decades.

Jan 1, 1998

By Desiree Willis

Disc cutters have determined excavation rates of rock tunneling projects for more than 50 years. First developed in 1956 by James S. Robbins, disc cutters (then 279 mm or 11 in. in diameter) were used to bore limestone of 190 MPa (27,500 psi) unconfined compressive strength (UCS) and were loaded with 7.12 t (15,700 lbs) each. Modern cutters have reached up to 508 mm (20 in.) in diameter and are typically loaded with up to 31.7 t (70,000 lb) to economically bore through the hardest of rock up to plus 400 MPa (60,000 psi) UCS. New developments, such as larger cutter diameters, are geared to increasing the bearing capacity and wear life of the cutting structure. This, in turn, increases cutter life, cutter load and cutter penetration. Disc cutters have also been re-designed on a small scale for use in hard-rock utility installations. Additional variables also affect the three factors, including cutter spacing on the cutterhead, cutterhead diameter and cutter materials.

Jan 1, 2007