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By P. D. Barrette

This paper deals with the flow of granular materials in bins. A hybrid Lagrangian-Eulerian numerical model is introduced. The model is based on Particle-In-Cell (PIC) advection, and continuum equations describing a Mohr-Coulomb criterion. Experiments were conducted to test and verify the performance of the numerical model. Tests were done using three types of particles. Measurements of material properties and flow rates were carried out. Video records were also obtained and used to examine flow patterns. The results indicate that the numerical simulations produce deformation patterns and flow rates which are in good agreement with the experimental observations.

May 1, 2007

By G. Bonifazi

In the present work the possibility to utilize the morphometrical and morphological characteristics of an articulate solids system in a slurry flow to monitorate and to control a continuous process is considered. This goal has been reached by mean of an optical system able to acquire, to handle and to process the pictorial information derived by a suitable hardware architecture designed to realize the best lighting, focusing and sampling conditions for the examined flow stream domain. The procedure has been tested using different flow stream slurries coming from different sections of a beneficiation plant. A suitable strategy and a consequent software architecture has been set up in order to assure to the system the necessary speed and the stability to achieve correct on-line measurements and control.

Jan 1, 1994

By E. Vesely, A. Saxena

"SAG mill liners are designed for protecting the mill shell and providing lifting power for ore charge and grinding media. Due to the impacts from the charge and the grinding media, the liner experiences dimple, plastic deformation, strain hardening, fatigue, peening and final failure. Because of the collisional environment directly measuring such dynamical loads is extremely difficult if not impossible. In this study we tried to evaluate the liner failure risk by simulating the collisions of solid particles with mill liner using Discrete Element Method (DEM). DEM simulation has been proved to be a very useful tool in evaluation of granular flow and its impacts on the solid structure. But there are certain limits in DEM coherently, such as the number of solid elements, the computer runtime, etc. Here we first present the general feature of the particle-liner collision in terms of impact force and collision energy. Then the effects of parameter selection is discussed. Our simulations show the fatal collisional event of huge impact force is very rare and the collisional events of low impact is much more frequent. The fatal event may contribute most to the liner failure. The rarity of the fatal events may be missed in a short runtime simulation. This technical challenge combined with lacking of criterion to evaluate varying impact loads in fatigue problems may further complicate the evaluation. Should we use the largest impact force alone or we should use the more frequent events is an open question and requires more effort. In order to evaluate the quality of liner design, we proposed a relative comparison method. In the end we show the implication and application of this method in liner optimization by a work example. In particular, the effects of the charge level of grinding balls and their size on the operation performance is presented.INTRODUCTION Grinding is one of the most important and expensive steps of mineral processing. A variety of grinding mills such as rod mills, ball mills, semi-autogenous (SAG) mills and autogenous (AG) mills are being utilized for comminution of mineral ores (Gupta & Yan, 2016). Up to today, SAG mills and AG mills have been widely used to reduce operation costs and increase throughput. In an AG mill, a rotating drum throws larger rocks of ore in a cascading motion which causes impact breakage of larger rocks and compressive grinding of finer particles. Unlike AG mills, SAG mills use steel grinding balls to break ores of size quite small such that they cannot be easily broken in AG mill. SAG mill liners are designed for protecting the mill shell and providing lifting power for ore charge and grinding media. Due to the impacts from the charge and the grinding media, the liner experiences dimple, plastic deformation, strain hardening, fatigue, peening and final failure. Quality and performance of SAG mill liners play a fundamental role to enhance efficiency of grinding mills, because failure of liners is the major cause for unexpected breakdown (Banisi, Hadizadeh, Mahmoudabadi, & Eilkhany, 2006)."

Jan 1, 2019

By D. B. Nazzer

"ANY DISCUSSION of energy today is incomplete without consideration of nuclear energy. In the Maritimes, with plentiful supplies of coal, with relatively easy availabilty of imported oil brought in to the deepwater terminals, with future sources of large supplies of oil and gas anticipated from under our neighbouring continental shelf, and with the Fundy tides, you may question why nuclear energy should be considered. What follows may not give you a specific answer to that question, but it may provide a basis for better understanding. Energy from the sun, from hydraulic sources and from combustion has been available to man from prehistoric times, for thousands of years, but the most sophisticated source of energy, the actual conversion of matter into energy by man, has been developed entirely within the last one-third century, since the discovery of fission in 1939, and the application to generation of electric power has all been done within a generation or less. The pressure of military needs during and after the second world war was largely responsible for the speed of initial development, by funding and focussing the effort needed to develop the basic technology, and in particular materials. The U.S. defence program yielded, for example, the large-scale isotope separation processes for fissile U'35 and for heavy water. The nuclear submarine program yielded zircaloy, a key structural material for the core of the Canadian Candu type reactor."

Jan 1, 1972

"Tell us how you got involved in mining?I was first exposed to mining at a young age, as a consequence of my dad and his passion for the industry and rock collecting. Even though he graduated with a degree in mining engineering from Washington State University, my dad spent most of his career working as a structural engineer for the Boeing Company. At the time, Boeing supported a range of employee activities and clubs, including one devoted to mineral prospecting, small-scale dredging and rock hounding. My dad was extremely active in the Prospectors Club, where as a family, we spent a good part of my youth tramping around the Pacific Northwest digging for mineral specimens and panning for gemstones and gold. On my mother’s side of the family, I had relatives that mined in Dawson City and Fairbanks, AK which left a family legacy of sorts. I loved the stories that my dad and a close buddy of his, who was a geologist, would tell about various operations and towns, as well as the wild times at the annual Northwest Mining Association (NWMA) meeting in Spokane, WA. My first recollection of ever being at a commercial operation was during a tour of the Bunker Hill Mine with my dad when I was 7 or 8 years old; this had to have been shortly before the May 1972 fire at Sunshine. That visit of the mine and processing facilities made a permanent impression on me. While I always knew there was something special about the Silver Valley, I began to understand why. To this day, I still get the same feeling when I visit historic mining districts like Leadville, Morenci, Virginia City, Butte, Silverton and Barkerville. During our summer excursions to Helena, MT to dig sapphires, we would usually make visits to Butte and watch mine operations inside the Berkley Pit and surface activities at the Kelly and Mountain Con. In high school, I did well in math and science and began entertaining thoughts of pursuing a degree in engineering. Above all, I wanted to go to a college in the West that had a good academic reputation, where I could also play football. As a 6-ft, 190-lb nose guard, my options for a Division I scholarship were pretty slim, and there weren’t that many technical schools in the Northwest that were Division II that offered athletic scholarships. As fate would have it, I was unexpectedly contacted by Marv Kay, a legendary coach at the Colorado School of Mines (CSM), and was recruited to play ball. Fortunately, I had a couple of high school friends who were already attending CSM, and I had just secured a summer internship with Asamera Minerals in Wenatchee, WA. It was as if all the stars had aligned, and, with the support of my parents, I made the decision to attend Mines. Despite the stress of getting through CSM during a period when the mining industry was in freefall, it was a great decision to attend Mines, and I’m thankful for all the opportunities, friendships, and faculty mentoring I received as a student"

Mar 1, 2019

By J. David Chapman

There are a variety of choices of materials for mineral extraction processing. Traditionally, end users have used metallic piping for fluid handling and little is known about the advantages (or limitations) of non-metallic piping systems. This presentation will review custom FRP pipe systems and their use in severe corrosive and erosive process streams. These systems can be designed to various pressure and temperature ratings and different components (such as resin and glass type) can be varied to suit the process conditions

By Jeffrey H. Welsh

This report presents a study on the use of computerized, continuous remote monitoring systems for fire and explosive atmosphere safety in underground coal mines. The effects of these systems on the safety level in mines are investigated, and the relationship between mine safety regulations and computerized, continuous, remote monitoring is analyzed.

Jan 1, 1982

By L. Callele, C. DiGiovanni, L. Li, R. Driver

"Hot-dip galvanizing is a common procedure used to protect structural steels from corrosive environments. However, in a construction project involving welded structural steel platforms by a Canadian steel structures company, numerous connections were found with large cracks in the welded corner joints and T-joints after galvanizing. Historically, in other similar projects by the same industry partner, cracking did not occur making this an unforeseen and new phenomenon. The project explored the mechanical properties of the base material, the thermal stresses induced by the hot-dip galvanizing, and the fracture surface of the cracks. A key feature to note, the fracture surface showed intergranular cracking with no plastic deformation. Lab testing showed the base material exhibited intergranular brittle behavior when heated and fractured at the galvanizing temperature. The transition to a brittle fracture mode is due to temper embrittlement and the segregation of elements in the grain boundaries.INTRODUCTION Galvanization is a common practice for protecting steel structures from the corrosive environment. Hot-dip galvanizing is the most common approach to bonding the zinc layer to the steel, and it is highly cost effective. In the case of welded structures, it is common to do the hot-dip galvanizing process after welding. This is so the protective layer can be applied to the structure as a whole and over the welds. In a recent construction project carried out in industry, a steel frame platform structure measuring approximately 3 m x 7 m was galvanized after welding fabrication. The structure was built of CSA G40.21 350W and CSA G40.20/G40.21 300W plain carbon steels and welded using a metal core arc welding process for the flanges and a flux core arc welding process for the webs of the beams. Due to their size, the platforms underwent a double-dip galvanizing process meaning half of the structures were submerged in the molten zinc path while the other half was exposed to the ambient air. This was repeated for the remaining side. Shortly after the galvanizing process was completed, numerous large cracks were found in the welded joints. Given there was no history of weld cracks after galvanizing in previous similar frames that were double dipped, this failure posed a new and curious problem."

Jan 1, 2017

By N. Del Bel Belluz

Drilling underground in the Grasberg De-watering drifts has routinely hit water aquifers with high flow rates and pressures. Two types of holes are utilized; pilot-holes to probe ahead of the tunnel development to intersect aquifers ahead of the face; and de-watering holes to de-water rock formations that will drain water from the Grasberg pit and allow tunnel development to proceed safely. Recently, rates of 1050 psi static pressure have been recorded with flows from a NQ hole measured at 1350 gpm (US). The water flows can be slightly acidic, necessitating the use of stainless steel collar gear to resist corrosion. These rates were anticipated and contingencies were planned early to deal with these conditions. The collar gear is used to control water flows whereby the water is treated as an important resource. As a result, pm has established procedures to maintain safety of the drill crews, enable coring of the rock and to maintain safety of the miners who are driving the drifts.

Jan 1, 1998

By S. Davis

It has been accepted almost as dogma that sampling contributes most of the error to fluctuations in gold fire assays. Differences in assay results on pulp material from the same sample interval are frequently regarded as evidence of the presence of the so called "nugget effect" or relatively coarse gold particles. It is true that if coarse gold particles are present they contribute to substantial sampling fluctuations, but while the process of sampling is probably the major source, the analytical process cannot -be completely ignored as a possible contributor to erratic assay results. In order to maintain a stable assay process, the analytic part of the system must be kept in control as well as the sampling and preparation part. One way of monitoring the performance of the analytic system is to systematically assay standard material whose sampling characteristics are carefully controlled. Gold assay standards are not prepared nor can they be prepared to account for both sampling and analytical errors. It is not possible to send coarse material to a lab for preparation (which includes both the processes of comminution and splitting) followed by fire assay, to make inferences only about the fire assay process. Because most gold ores are very heterogeneous, sampling errors would in most cases completely mask the contribution of the analytical errors. Assay standard material is prepared only to assess the accuracy and variability in the fire assay process.

Jan 1, 1995

By A. J. Martin, M. J. Peoples, D. J. Adams, A. Opara

"The weathering of coal mine waste rock releases iron, calcium, sulfate and associated trace elements like selenium (Se). Nitrogen species are also found in association with coal-mining drainages mainly due to the leaching of residual blasting compounds. Elevated concentrations of Se are a ubiquitous occurrence in coal-mining environments in British Columbia. A major concern with waterborne Se in British Columbia is the potential for its bioaccumulation in aquatic food chains.Treatment to remove Se from coal-mining waste waters has proven to be challenging for conventional water-treatment technologies. Compounding this challenge, many streams are characterized by high flows and low selenium concentrations. Conventional membrane and ion exchange treatments produce concentrated brine streams that are difficult to treat or require disposal. Conventional biotreatment systems use excess nutrients to provide the required electrons to compensate for inefficient and variable electron availability, as well as to adjust reactor chemistry.This paper's electro-biochemical reactor (EBR) technology provides a controllable and consistent supply of useable electrons to the microbes directly at a low voltage potential (1-3 V) and low current. In this manner, the EBR technology overcomes the shortcomings found in conventional systems, as it reduces the required nutrient addition and provides a more controllable, efficient, economical and robust biotreatment system. Additionally, the EBR process does not produce excess solids or biomass; therefore, solids management post-treatment is not required.Laboratory EBR bench-scale and on-site pilot-scale systems were used to treat five British Columbia coal-mine waste waters; influent Se concentrations ranged from 35 µg/L to 531 µg/L. Se treatment targets for the tested waters ranged from 5 to 10 µg/L. Mean Se concentrations in EBR effluents ranged from 0.5 µg/L to 1.4 µg/L, while reducing sulfate concentrations. The test data demonstrate that the EBR technology is an effective Se removal option for British Columbia’s coal-mining waste waters.IntroductionSelenium in Mining. Selenium (Se) is a naturally occurring trace element, which is an essential nutrient in small amounts (Thompson and Robinson, 1980; Brown and Arthur, 2001). However, it is also toxic to aquatic life, birds, and humans at very low concentrations. A major concern with waterborne Se is the potential for its bioaccumulation in aquatic food chains, resulting in acute and/or chronic toxicity to fish, water birds and amphibians (Besser et al., 1996; Conley et al., 2009)."

Jan 1, 2015

By E. K. Albert

In 1977, Congress enacted Title IV of the Surface Mining Control and Reclamation Act (SMCRA), providing for an "abandoned ml.ne reclamation fund". This fund, taken from a fee collected from operating coal mines, provides capital for the reclamation process. However, given the number and extent of abandoned mine sites in some states, the question of project selection is important. This paper describes a project in progress to create a Management Information System application for project ranking under multiple objectives. The benefit of this project for the need of new environmental control technologies will be discussed.

Jan 1, 1990

By W. D. Bonisteel

In 1976, Rio Algom Limited began the expansion of uranium production facilities at Elliot Lake. Quirke Mine was the only property in operation at the time, and plans were made to expand its milling capacity from 4,500 to 7,000 tons of ore per day. Following this expansion, other properties in the area will be reactivated to fulfill long-term contracts for uranium. As part of the expansion program, it was decided that in view of the escalating cost and impending shortage of energy, heat reclaim and conservation would be employed wherever practicable. In general terms, heat reclaim applications fall into three main classifications: ventilation, utility and process. Two of the ventilation applications and one process application will be described in some detail. Several other systems will be presented briefly as a matter of general interest. Some future possibilities will also be mentioned, together with their potential for economical heat recovery.

Jan 1, 1979

By K. Sakai, M. Miyaue, T. Aoki, T. Tani, S. Tanaka, N. Kudo

In the planning stage of a tunnel, due to limited available technology in the geological survey and the financial restriction, tunnel supports are often designed from unsatisfactory information, and the tunnel construction is started. Therefore, "observational construction" is carried out in the construction stage, in which the design is rationally verified and modified by observations/measurements. Moreover, the ground conditions ahead of a tunnel face must be predicted for efficient and safe tunnel construction. The authors have examined effective prediction methods to the ground conditions ahead of a tunnel face under construction of a mountain tunnel (Aoki et al., 2010) in view of the established method (Schubert et al., 1995). Though the prediction method of Schubert et al. requires the displacement in the direction of tunnel axis, it is difficult to obtain its accurate data by the electro-optical distance meter. Then, we have proposed a method that uses tilt sensors installed at the tunnel crown near the face to obtain the slight tilting information. To measure inclination of the tunnel crown, this inclinometer was originally developed as a daily management measurement, such that the geological condition and its possible change behind the face could be detected early, and a steady advance and construction safety could be ensured. This paper describes the method of forward prediction mechanism and advantages of this proposed method. It then presents the typical results of a field demonstration test at a tunnel under construction. Lastly, the predictable range from the stratum boundary at which ground stiffness changes are discussed based on the results of three-dimensional numerical analysis.

Jan 1, 2015

By Norman Paley, John Kells

The climate and location of the Red Dog Mine present several challenges to blasting operations. The mine is located north of 68º latitude, in an area of continuous permafrost. Ground temperatures are below freezing year-round and air temperatures range from -40 to 70°F (-40 to 20°C). Because there is no overland access to the mine, the entire year’s supply of bulk explosives, approximately 7,000,000lbs (3,175,000kg) is shipped in by barge during the 100 day shipping season when the port is ice-free. The first week in July is the earliest that new product arrives at the port. Emulsion usage is maximized from mid April through October when surface water fills the blastholes during drilling. This necessitates that a considerable portion of the bulk explosives are stored for 10 months or more before usage. The emulsion is routinely pumped from the ISO containers at temperatures of 20ºF (-7°C). The mine engineers conducted a testing program during the 2001-2 blasting season to identify the bulk explosives best suited for the conditions at the mine. A secondary goal was to decrease the usage of sensitized emulsion, as this is the most difficult portion of the explosives order to ship. To ensure repeatability when transferring the results to the day-to-day blasting operation, the majority of the testing was incorporated into normal blasting operations in the field. The mining methods used at Red Dog Mine make direct fragmentation analysis impractical and performance testing in the field relied primarily on VOD measurements. The products were also tested for their ability to be pumped in cold temperatures.

Jan 1, 2004

By C. Sun

With complex component, higher salt content, low biodegradability, DSD acid oxidation wastewater could not be efficiently dealt with traditional methods. It is pointed that the coal water slurry could be made with DSD acid oxidation wastewater of different concentration and the density of coal water slurry could be up to 70%, while its viscosity is only 850~930 mPa?s. The coal water slurry could be perfectly jetted and burnt under different conditions. The higher density the DSD acid oxidation wastewater has, the better properties the coal water slurry have. The pollution components and characteristic group of DSD acid oxidation wastewater are similar to the additives of coal water slurry, so it could be used as a kind of usable additive of water coal slurry. It is so reasonable and feasible to make coal water slurry with DSD acid oxidation wastewater that the pollution of DSD acid oxidation wastewater can be solved completely.

Feb 23, 2014

By L. Magne, A. Pinto, M. Maldonado, J. A. Finch

Estimation of gas holdup from electrical conductivity measurements has been used in lab and industrial installations. The approach is based on the application of Maxwell's model, which relates the concentration of a dispersed phase in a continuous medium to measurements of the electrical conductivity of the dispersed phase, continuous medium and the resulting mixture (dispersion). When applied to inferring the collection zone gas holdup in a three phase system and to facilitate real-time on-line measurement, the slurry is assumed to behave as the continuous medium and gas bubbles as a nonconducting dispersed phase. This article derives an equation for estimating gas holdup in a three phase system, eliminating the assumption that the slurry behaves as a continuous medium but rather as a dispersion of non-conducting solid particles in water. In this formulation only water behaves as the continuous medium in the sense of Maxwell, and gas holdup in a three phase system is then calculated from the application of the Maxwell model twice: (1) to determine solid content in a two-phase system, and (2) to determine solid plus gas holdup in a three phase system. To validate the new equation and quantify the errors incurred by assuming slurry is the continuous phase a laboratory flotation cell was instrumented to continuously measure the conductivity of two and three phase dispersions with known solids contents. As the amount of gas in a lab flotation machine is difficult to measure directly or by another indirect technique such as using pressure signals, 2.5 mm dielectric plastic spheres having a density of ca. 1.3 g/cm3 were used instead of air bubbles for validation. Experimental results demonstrated that the continuous medium assumption underestimates gas holdup and that the resulting bias error increases linearly with the solid content and decreases with the magnitude of gas holdup.

Jan 1, 2016

By Peter F. Pullen

The need to apply the latest available technology to develop better tools and methods to meet problems in the mining industry was recognized by six of Canada's leading mining companies. As a result, MIROC (Mining Industry Research Organization of Canada) was chartered to identify problem areas in Canadian mining and to have research carried out to develop the tools and equipment to meet these perceived needs. The initial activity of MIROC has been in the environmental field, with improved clothing and protective devices being developed by contractors. Work clothing for miners is now being field tested. Respiratory protection and a new personal light source combined in a new "space-age" helmet are about to be issued for testing. Further developmental work is being carried on to offer these units and probably other personal protective devices on an individual basis as well as in a combined package.

Jan 1, 1979

By Georgene Renner, Chee Theng, William Gleason

"More than 6,300 people attended SME’s 2016 Annual Conference & Expo in Phoenix, AZ and many of them made the trip to the conference to take part in the excellent technical sessions that are presented on a yearly basis by the Society.Holding true to form, this year’s conference was full of options. In fact, this year there were 121 technical sessions and 751 presentations to chose from. The following is a sample of some of the technical sessions as seen through the eyes of the editors of Mining Engineering and SME technical papers.SME Sections Sharing Success: Changing thePublic Perception of MiningThis session was a workshop on how several local sections were effective in getting the message out to their communities and schools about the value of the extractive minerals industry. Several sections shared their outreach successes, including the Mining in Society merit badge activities by the Minnesota Section by Julie Lucas and SME’s participation in the World Scout Jamboree in Japan by Frank McAllister.Dan Alexander highlighted activities by the Pittsburgh Section, such as preparing minerals kits and pamphlets for elementary school classes and regional science fairs. The West Virginia University Student Chapter used the kits as handouts at their local gem and mineral show. School speakers in full mining gear were especially interesting to the young children.Other speakers were Michael Linn, Paradise Valley Unified School District — Business and School Partnerships; and Greg Kruse, Central Wyoming Section of SME — What makes a successful section?Engineering Competency ModelAmerican Association of Engineering Societies and the U.S. Department of Labor, with a grant from the United Engineering Foundation, developed a guide to the set of skills necessary for success in the engineering community -- Knowledge – Skills – Abilities — needed for all disciplines.Various engineering societies are now writing the Tier 5 occupation-specific requirements. The Competency Committee is charged to write concise and discipline-specific mining engineering, mineral processing engineering, geological engineering, and geophysical engineering by Sept. 30, 2017."

May 1, 2016

By Susanne Pignolet-Brandom

Reflected light microscopy, and scanning electron microscope energy dispersive spectroscopic analysis and backscatter electron images were used to determine if a "slick dross" with undesirable handling properties has an assemblage of phases distinct from normal dross. This study has found that in the normal dross the most abundant lead phases are lead sulfide and lead metal and the most common copper phases are copper-iron sulfide and copper sulfide. In the slick dross, the most abundant copper phase is copper-lead sulfide and the most common lead phases are copper-lead sulfide and lead sulfide. The resulting mineralogical information has provided additional insight into the causes of the handling problem and the reaction mechanism for the formation of normal and slick dross

Jan 1, 1988