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By Michael Amick

Over the last few years as the coal industry has seen an increase in the price of coal, a renewed interest in the additional mining of pre-law highwall sites has occurred. Much premium coal and property remains behind these pre-law highwalls but access to mining is limited because prior mining used auger machines to remove coal from under the highwall. Older augers seldom reached more than 200 feet and often no more than 100 feet but this zone of auger holes destabilizes the highwall to where additional mining is often unsafe. If the reserve is large enough, the highwall can be stabilized with common flyash and cement grouts to form a face-up for an underground mine but this expensive method is usually not practical for continuous use with a highwall mining machine. It is estimated there are hundreds of miles of highwall riddled with auger holes where the coal reserve available is ill-suited for deep mining for a variety of reasons. However, these same properties are ideal for additional mining with state-of-the-art highwall mining machines that have a reach up to 1200 feet, except to the relatively thin auger mined de-stabilized zone. The renewed interest in highwall mining these properties has driven research into finding an economical way to stabilize the highwall so the highwall mining machine can recover additional coal. This research discovered and fine-tuned a process that is economical and is successfully supporting the highwall at a highwall mining operation. This paper discusses the research involved in determining the strengths need, the methodology used to place any grouts, the effect on mining plans and the increased recoveries. ARMPS-HWM is used extensively in this research. The failure of the highwall, when not grouting, and the success, when grouting using the new materials and equipment utilized, confirmed the ARMPS-HWM method.

Jan 1, 2007

By G. F. Revey

All underground operations have limiting factors that influence overall profitability. Hoisting, hauling, available headings, labor, milling capacity and other factors limit how much material can be removed from an underground mine. Consequently, when mines use limited labor to handle the additional rock from overbreak and to perform extra ground support tasks, productive activity is replaced by non-productive work. Mining economics are further penalized when overbreak causes dilution of ore grades. This paper reviews organizational systems that mines have used to create environments which foster the creation of successful overbreak control programs. Actual case histories document the various quality improvement techniques, worker incentives, and practical project management systems used by these mines. A brief review of controlled blasting technology sources and overbreak measurement tools is also included.

Jan 1, 1997

By Alcides Eloy Cano

Los recursos minerales de un depósito está en función de las dimensiones de la geometría del cuerpo mineral, así como sus reservas minables permiten saber el verdadero valor económico de su contenido. En este sentido, la Geotecnia es una herramienta que define las condiciones de los esfuerzos in situ, predice el comportamiento alrededor de excavaciones subterráneas e interactúa con las labores próximas, así como también la distribución de esfuerzos. Por ello, el presente trabajo señala la aplicación de esta herramienta a una mina subterránea de Oro localizada en el Perú, donde se tiene bloques de mineral económicos, así como señala su accesibilidad con leyes encima del Cut-Off. De forma que se recupera el mineral económico a través de las rutas críticas de carguío, en función de la viabilidad de autosostenimiento.

Sep 12, 2011

By Bruce Richardson

A contractor-manufactured 4.75m (15'-7") diameter EPB shield excavated a 115m (375 ft) long tunnel under the San Antonio River as part of the Salado Creek to Dos Rios Pipeline Interconnect Project in San Antonio, Texas. Lignite, limestone concretions, and sandstone in the face of the tunnel required the use of disc cutters. Less than 7.6m (25 ft) of sand and gravel hydraulically connected the top of the tunnel to the channel of the river. Fully lagged steel ribs with filter fabric were used for initial ground support and water control. This and other contractor manufactured TBMs in the 1.2 to 4.75m (4 to 16 ft) range are presented with descriptions of the jobsites, equipment, performances, and problems.

Jan 1, 2008

By Mansour Asri, Philippe Somogy, Youssef Daffi, Amor Karim

Very few cases of Cast Blasting use in phosphate mining are reported. However, in open-cast coal mining, Cast Blasting is a common practice. And yet, the geological structure of both types of deposits is similar. Accordingly, advantages for phosphate open-cast mines are manifest, especially as future conditions of phosphate deposits fit quite well with the approach.

Jan 1, 2015

I would like to thank The Australasian Institute of Mining and Metallurgy for inviting us to share with you some of our experiences in the handling, storage, and transportation of industrial minerals in North America. Cometals, Inc. is a wholly-owned subsidiary of Commercial Metals Company, headquartered in Dallas, a public corporation whose shares are traded on the New York Stock Exchange. Sales exceed one billion dollars. Cometals, Inc. is located in New York and specializes in marketing of chemicals as well as raw materials used in the manufacture of steel, refractories, abrasives, glass and ceramics. This makes us one of the larger regular shippers of industrial minerals. Many people are aware that industrial minerals need to be viewed and judged on the merits of their chemical and physical characteristics. In addition you are surely aware that close attention must be paid to the economics of these minerals to determine the appropriate value and competitiveness of the minerals or products delivered at the doorsteps of the consuming work. You may, however, not be aware that the handling and transportation of the mineral is of crucial importance, in fact, the transportation and handling costs of industrial minerals frequently are a major component of the value of the ores marketed and, therefore, it is only natural that close attention should be paid to them. Many of the industrial minerals require special handling to assure that the material reaches the consumer without being contaminated and without getting wet. I invite you to accompany me through the various steps involved in "delivering the goods" to the consumer.

Jan 1, 1989

By Raymond Chenier

British Columbia (BC) is Canada’s most western province. The landscape in BC is amongst the most beautiful and pristine in the world. Along with its beauty come vast mountain ranges, coastal rain forests, swamplands, deep river valleys, and almost every type of landscape imaginable. These all have, or at one time had, logging roads constructed. Some of these areas should never have had roads constructed due to poor drainage and unstable slopes, but some of the roads could be considered engineering masterpieces. To navigate a vehicle the size of an off-road logging truck down the side of a mountain with an 80°h side slope or greater can be a hair-raising experience. Not to mention coastal rains and/or high elevation blizzards. These factors collectively make logging BC’s most hazardous occupation. People are seriously hurt, sometimes even killed everyday.

Jan 1, 2001

By Lee T. J

The area, A, under a gamma-ray log that passes through a horizontal bed given by: A = gl/k. Here is the equivalent concentration of U3O8 in the body, l the thickness of the body, and k the calibration factor or sensitivityof the logger. The area is independent of the logging speed or logger time constant.This relationship, together with the first moment about the maximum of the log and its value there suflicient to determine the thickness, position of the centre of the bed from the log maximum and the concentration of U3O8.Numerical results obtained from artificial and field data show that the computed results arc as good as those obtained by methods such as the inverse filter technique and the iterative method. The present method yields results that arc easier to feed into an ore reserve data base.

Jan 1, 1981

By C. Sun

The Leeville underground mine has been in operation since 2006 and currently produces 3,500 tons of ore per day with an average gold grade of 0.34 opt. The mine has a large horizontal extent of 2,500 feet by 500 feet and a vertical extent of 20 to 200 feet. Based on the characteristics of the ore bodies, a long-hole stope and cut-and-fill mining methods are used at the deposits which are divided into several mining zones. Cemented rock fill (CRF) is used as the backfill in the open stope. CRF design includes the aggregate design, the ratio of cement and fly ash design, and strengths for the long-hole stope and cut-and-fill. In the aggregate design, the particle size distribution is one of the most influential aggregate characteristics in determining how it will perform as a basic backfill material. Gradation helps determine durability, porosity, cement and water requirements, strength, and shrinkage. To cut the backfill cost, fly ash usually is added into the binder to replace some part of cement. However, adding fly ash can affect the strength of the backfill. The reasonable percentage of fly ash is also important for making a good and low cost backfill. Based on the different mining method, the different backfill with different strength is designed. A systematic quality control procedure for aggregate and backfill is followed. After four yeas application, CRF system in Leeville achieved very good results.

Jan 1, 2011

Up to the end of World War n, flat-back cut and fill stoping with or without square sets was the universal method of ore extraction. Rapid changes in practice occurred during the post-war years; first, ore extraction was fully mechanized; secondly, the stope design for new levels, notably No. 17 Level Zinc Corporation Ltd. and No. 19 Level New Broken Hill Consolidated Ltd., was modified to suit this mechanization; and thirdly, sub-level and shrinkage stopes were developed in orebodies where cut and fill methods would be uneconomical. The following is a brief survey of the changes that have occurred-most of which were inaugurated during the last five years.ROCK DRILLINGDuring 1951 open stoping was investigated in detail. In order to reduce steel handling problems, forged steel onepass detachable bits were introduced, but were soon superseded by the "Swedish method". Investigation showed that when using a bar and arm mounted 3-in. drifter the overall drilling time was approximately 6 min. per ft. compared with 4 min. per ft. using the light jackhammer-airleg combination with 1-in. hex. by 4-in. collared shank tungsten carbide-tipped steel.Although competitive with tipped steels on a cost per foot drilled basis (excluding miner's time), detachable steel bits proved most unsatisfactory for hard drilling conditions.Rapid blunting necessitated frequent bit changes and thus caused lost drilling time. This, together with rapid gauge...

Jan 1, 1957

By Jay R. Schafler, Jacob L. Brinkman, Catherine E. Johnson

"The United States coal mining industry is currently experiencing a decline in both demand and commodity price while facing implementation of more stringent air and water pollution regulations. Company profits have decreased significantly, forcing several major companies to declare bankruptcy. The industry was required to adapt to survive. Many of these companies have adjusted by abandoning mines; the last two decades have seen a drastic decrease in the number of mines. To discover the primary causes of this downturn, three major aspects must be studied: properties of abandoned mines, commodity history and regulatory impact. Trends since 1994Each year, U.S. coal mines are required to submit data on a variety of categories to the U.S. Mine Safety and Health Administration (MSHA) and the U.S. Energy Information Administration (EIA). This data include administrative records, production values and information regarding the attributes of the mined material and the mine itself. Each year since 1996, EIA has released a report summarizing the data from two years prior. Additionally, MSHA maintains a database containing a collection of all the most current data. These resources are the primary sources for the figures included in this article. There are several items to note regarding this data:1. The EIA reports from 2016 and 2017 were not released at the time of writing this report.2. The MSHA data set is actively maintained as information is provided. This means the data for 2016 is from June 27, 2016 and data for 2017 is from Aug 24, 2017. All other points represent the end of-year values.3. Each of the figures only includes data pertaining to active mines. EIA defines active mines as both active and temporarily idled mines, and inactive mines as nonproducing and abandoned mines. MSHA separates all four into separate categories, though this paper combines the MSHA values according to the EIA definition for the purpose of comparison."

Jan 10, 2017

By W. R. Dengler, R. S. Brown

In 1974, Brunswick Mining and Smelting Corporation Limited started a 48 million dollar expansion programme at their property in Bathurst, New Brunswick. A portion of the expansion plans includes a 26 foot diameter 4,525 foot deep shaft, underground crusher and conveyor excavations and lower level access development. J. S. Redpath Limited was awarded the contract for the new shaft and associated rock work in May 1974. Brunswick Mining and Smelting Corporation Limited, a member of the Noranda Group, operate this 10,000 ton per day lead, zinc, copper plant with proven reserves in excess of 90 million tons. While most of the ore is provided by the underground operation at the Number 12 ore body, some tonnage is produced from the open pit at the Number 6 ore body. Long range plans indicate a phasing out of the open pit and an increase in production from the underground operation. Existing facilities at the underground mine could not provide additional tonnage, thus the requirement for a new shaft. (Figure 1) The new shaft will also provide access to ore below the 2,800 level which is currently the bottom level of the existing facility. The contract called for sinking a 26 foot inside diameter, nine compartment concrete shaft 4,525 feet deep (Figure 2). Station access and ramp development from existing workings would be required to the bottom of the new shaft. In addition, development work for new crushing and conveying facilities was needed simultaneous with the shaft sinking.

Jan 1, 1976

By Bradford F. Townsend

A study was made on six collapses that occurred during large-diameter tunnelling through weak sedimentary rocks and soil using SES methods in three stages?top heading, bench and invert. The collapsed lengths are between 20 m and 277 m. The collapses were re-mined using essentially the same tunnel-ling method with larger excavation profiles to accommodate the designed remedial measures consisting of ground treatment, pre-support and stronger initial support/outer lining required to carry higher ground loads acting in the collapsed lengths. The paper presents information on the collapses and the design and execution of the remedial measures.

Jan 1, 2008

If the industry keeps doing what it has always done, it will continue to get what it has always got - rising operating costs. Why is this so? Generally grades being chased are becoming lower, stripping ratios becoming higher, ability to attract personnel to the industry becoming harder and/or more expensive, higher safety standards are being demanded and environmental governance is being enforced.   How then should the surface mining industry plan for the future whilst delivering on improved safety and the environment? In-pit crushing and conveying (IPCC) points the way, as a partial or complete substitute for trucks.   IPCC systems promise significant advantages over traditional truck and shovel operations, including improved safety, reduced operating costs, reduced dust and noise emissions, far greater efficiency in energy use (electric versus diesel motors predominantly and the ability to regenerate electricity back into the local grid for downhill situations), reduced carbon emissions (dependent on power generation source) and reduced water consumption. Despite these advantages, there is a general industry reluctance to migrate from truck and shovel operations. This reluctance stems from a familiarity with truck and shovel operations and a perceived concern that IPCC lacks flexibility which will negatively impact on the mining operation.   In studies conducted since 2007 (with the new modular builds) comparing IPCC with truck-optimised pit designs, IPCC has delivered up to USD$0.82 per tonne moved less than an equivalent truck operation. In addition, IPCC is easily automated from a central control room (local or remote) - something that trucks have yet to commercially achieve.   IPCC is a proven process that, with a fresh mindset, can make a significant improvement to mining operations - its safety, the impact on the environment and its costs. It maybe of interest to note that there is over 200 IPCC installations worldwide today.   This paper and presentation will assist in furthering the understanding of IPCC and its applicability.

Jun 1, 2010

By T. Mal

A test system was developed at the National Institute for Occupational Safety and Health's ventilation test gallery for measuring airflow using a three-axis ultrasonic anemometer. The gallery war used to simulate face airflow conditions in underground mines having a blowing curtain. Airflow data, collected at multiple sampling locations between the face and the end of the curtain, were used to draw airflow profiles for different curtain setback distances, intake flow quantities and entry widths. In addition, methane was released at the face, measured at the sampling locations and displayed as methane distributions in the area between the curtain and the face. Entry geometry had a significant effect on airflow patterns, and the flow patterns affected the distribution of methane in the entry. Flow measured at and parallel to the face was a good predictor of methane dilution and removal within 0.6 m (2ft) of the face.

By Jom Kresta

Fundamental changes in the Bitumen Production process at Syncrude have led to the integration of Mining and Extraction operations. Successful operation of the integrated process requires the coordinated effort of several business units. Hence, decision-making has become increasingly more complex and better tools are required. IO2 is a collaborative effort to develop a proof-of-concept prototype of a distributed decision-support system for integrated short-term production and maintenance planning with fleet allocation and dispatching. The prototype includes three main modules (planning, dispatch, and maintenance), a shared database, and a simulation module. At this stage, this prototype is used to plan and operate a simulated mining operation. It is used to demonstrate the viability of the chosen systems architecture and algorithms, as well as the information flows and interactions necessary for improving the overall performance of the integrated operation. While the problem is demonstrated using Syncrude?s site, the methodology is applicable to most integrated resource allocation problems.

May 1, 2002

By Peter Richards, Alexander Lewis-Gray, Mark Davies, Nicholas Katsikaros

"Gekko Systems developed the Gekko Resin Exchange Column (G-REX) in order to optimise the recovery of gold in complex leach-to-electrowinning processes, as an intermediate step using a highly gold-selective resin to isolate contaminant metals. The AuRIX®100 resin produced by Purolite is licensed exclusively to Gekko, with the G-REX column designed specifically for this resin (Lewis-Gray et al, 2015). Operational experience has been gained at the CGT Ballarat Gold Plant in near continuous operation since 2008, treating unclarified concentrate leach solution. The extension of the technology to higher throughputs and more complex chemistry is discussed.Aurix®100 ResinAuRIX®100 resin is a cross-linked polystyrene alkaline resin developed by Henkel (Virnig et al, 1996). The resin beads are off-white in colour, spherical, with a nominal size of 100% +600µm. This resin is highly selective for gold and silver over many metals, by way of extracting precious metal cyanide complexes from leach solutions with a pH less than 11.5. The higher end of the pH scale produces best selectivity according to the order of preference: Au > Ag > Hg > Zn > Ni > Cu > Co > Fe. Purolite produces the resin and Gekko Systems maintains licensing of AuRIX®100 resin for use in its G-REX column as part of its unique suite of gravity gold handling equipment.Significant cost savings over carbon-in-solution (CIS) systems are realised with AURIX®100 resin, of around 4% to 12% in capital savings and 27% to 40% in operating costs (Virnig et al, 2004). Allied to this is that AuRIX®100 resin is not susceptible to fouling, that is, the resin does not load with inorganic salts or organic compounds which would affect the loading and extraction of precious metals. To counter any potential for fouling by inorganic salts, in service a dilute acid wash is carried out periodically on the resin to unblock resin pores."

Jan 1, 2016

The National Mining Association’s (NMA)MINExpo International ’96 is shaping up to be the organization’s largest. About 30,000 mining industry business and technical professionals are expected to descend on Las Vegas, NV Sept. 9-12 to take part in the 25 technical sessions and visit the more than 900 exhibitors who will be showing off their products and services. MINExpo will be the largest mining equipment and services exposition in the United States this year. Exhibits at MINExpo will fill the Las Vegas Convention Center, parking lots and part of the Hilton Center, located next door to the convention center. NMA estimates that this year’s show will cover more than 46,450m2 (500,000 sq ft) of exhibit space. Some of the exhibits on display will include haultrucks, hydraulic shovels and excavators, conveyors, continuous miners and tunneling machines. In addition, an array of computer equipment and software will be demonstrated. A new feature this year will be a helicopter pavilion, located in the Hilton Center. Helicopters and fixed-wing aircraft have become indispensable to many remote mining operations. NMA said that at least one full-size helicopter will be on display.

Jan 1, 1996

By W. Pariseau, S. Puri, S. Schmelter

Introduction Joints often have profound effects on elastic properties and strength of rock masses and therefore on rock slope stability. In surface mine slopes, joints are usually too numerous to be taken into account individually, so an equivalent properties approach is necessary. Previous work that treats a jointed rock mass as an equivalent composite material of joints and intact rock between resulted in excellent agreement between estimated and true rock mass elastic moduli in case of fully persistent joints (e.g., Pariseau, 1999) Rock mass failure mechanisms on joints and through intact rock were retained obviating the need for an equivalent rock mass strength. Impersistent joints, which are not continuous on a joint plane, can be accommodated (Pariseau, 2003). However, slope stability analysis of a large, deep copper mine indicated a need for computational efficiency even in two-dimensional analysis of vertical sections through pit walls (Puri, 2006). The analyses by the popular finite element method used small elements of bench size near the pit slopes and much larger elements away from the pit walls. The reasons for the graded meshes were numerical quality (small elements) and computational economy (large elements). Small elements contained only a few joints, while the larger elements contained hundreds of joints and led to impractical computation run times (days!). A new modeling procedure that recognizes sufficiently large elements as representative volume elements (REV’s) overcomes this obstacle. A companion improvement recognizes the concept of a representative area element (RAE) in association with joint impersistence and the probability that joint material occupies a considered site. Both are steps towards greater model realism and a practical slope stability analysis procedure. Consider the open pit mine photo shown in Figure 1(a), a companion plan view in Figure 1(b), and the problem of slope stability where high slope angles favor economics but low slope angles favor safety. These competing factors in surface mining generally result in some sections of the mine that have unstable slopes that require monitoring and perhaps mitigating action to improve stability. Although stability of a given section may not be easy to quantify with a single number, useful design guidance can be obtained from a finite element analysis of a proposed mining sequence leading to future pit slopes and profiles. The presence of water from rain and snow melt indicates a need for a coupled analysis that links water pressure, effective stress and total stress (Schmelter, 2001).

Jan 1, 2007

By Niklas Frank

Ore and waste transports form an integral part of any mining operation and represents a substantial portion of the mine´s total operating cost. Mine layout, truck fleet and size, production rates, haulage distances, shift schedules, maintenance strategies etc. are all important and not at all static variables. They all change during the life of a mine and interact in a dynamic way. It is therefore essential for the successful mine management to constantly analyse and optimise the mine's transport systems. Önnerlöv has recently conducted a life-of-mine haulage simulation project for Zinkgruvan Mining, a medium sized, underground zinc producer, located approximately 60 kilometers south of Örebro, Sweden. The main objective of the project was to analyse and optimise the investments required to provide ore and waste haulage under changing conditions over an +10- years period: Deepening of the mine, increased production rates, changed mine layout, changed truck fleet etc. A large number of scenarios has been tested in the simulation model in order to identify the "lowest cost per ton" solution. This paper comprises an introduction of Zinkgruvan Mining and a brief background to the actual project, a description of the simulation model, project conclusions and some useful hands-on tips for mining engineers and project managers how to run a successful simulation project.

May 1, 2003