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By R. J. Visintainer, J. M. Furlan

"Due to the time-consuming nature of froth testing in a laboratory environment, practical limitations require the development of a method of applying a single set of performance test data (Visintainer and Whitlock, 2012) obtained for a single froth pump at a given speed to a range of froth pump speeds and sizes, % air content and liquid viscosities. Head, efficiency and flow all vary as functions of both liquid viscosity and air content. As such, it is necessary to develop a technique that can be used to interpolate from existing test data in order to predict froth performance for pumps of various sizes running at variable speeds. Details of the technique developed in order to achieve this goal, as well as the insights gained from analysis of the resulting regressions, are discussed. Additionally, comparisons are made between the performance predictions of this test-derived method and those of the Hydraulic Institute standard for the effects of liquid viscosity on centrifugal pump performance (ANSI, 2010).IntroductionPump performance data (Visintainer and Whitlock, 2012) has been collected for a froth pump using an experimental loop outfitted with an array of pressure transducers, mass flow meters, an inverted U-loop, magnetic flow meter and an assortment of other instrumentation. Experiments were performed on pure water, water and air, pure corn syrup, and corn syrup and air. Data was obtained for % air contents of 0-30% and viscosities of 1- 15,000 cSt at eight specific valve positions (eight different flows as a percentage of best efficiency flow points) and the viscosity was changed by allowing the system temperature to increase during testing. The test pump is a 710-mm diameter impeller, GIW HVF, open shrouded, vented design that has its discharge axis oriented at 45° upward from the horizontal. A schematic diagram of the froth pump test loop can be seen in Fig. 1."

Jan 1, 2015

By Donald P. Richards, William M. Greenslade, Daniel E. Albers

INTRODUCTION The application of oil field technology to large diameter hole drilling is beginning to offer a cost effective alternative to conventional shaft sinking methods. The drilling of ventilation and small production shafts are, of course, not new. The major constraint to the drilling of large diameter production shafts has been the inability to drill holes large enough and straight enough to install and operate relatively high volume hoisting equipment. This paper discusses recent advancements in drilling technology as applied specifically to large diameter holes for use in the mining industry. The paper emphasizes the geotechnical and hydrologic considerations in assessing site conditions and their application to drilled shaft technology. The authors worked together on a recent feasibility study for a 6 m (20 ft.) diameter 975 m (3,200 ft.) drilled shaft in New Mexico. Their individual experience in drilling and geotechnical investigations related to shaft sinking is world wide. DRILLING TECHNOLOGY Large diameter hole drilling has been a natural evolvement of oil well rotary drilling techniques. Most problems that were encountered in the rotary drilling of large diameter holes have been

Jan 1, 1981

By James Wm. White

Computer based dispatching in open pit truck haulage operations yields many benefits of current interest to mine management. The key tangible benefit is a substantial productivity increase with a given fleet of equipment or, alternately, a significant reduction in equipment required to meet production quotas. Other tangible benefits, depending on the operation, include minimizing rehandle, meeting several blending constraints simultaneously and ensuring a target plant feed rate. Intangible benefits include production forecasting, performance comparisons of trucks or shovels of different manufacture and extensive on-line report generation. Recent advances in mini and micro computer hardware and software and solid state electronics permit design and implementation of system features not feasible even a few years ago. Here we discuss many of these recent developments with emphasis on system aspects and dispatching algorithms.

Jan 1, 1983

By R. L. Loofbourow

The Sunro Copper Mine is near the south coast of Vancouver Island about 35 miles west of Victoria. Failure of the roof of a large open stope let a good sized mountain stream into the mine. Broken are, boulders and sand were washed into the underground mill and out through a 7 800-foot adit. The adit became plugged; water burst out an a ridge above the adit, washing out the portal and o trestle by which it was reached, Rock and ore are strong but several systems of steep, pronounced but generally tight fractures are found on and parallel to the walls of the orebody. The stope was started from a slusher drift 390 feet below the bed of the River and brought up to an elevation 155 feet below the River by blasting vertical and horizontal rings of longholes in the nearly vertical orebody. Mining was stopped there and five months were given to grouting and bolting the pillar under the bed of the River, During this time and for several months thereafter sloughing increased the width, length and height of the stope. At the last known observation the stope was 77 to 96 feet wide, 185 feet long and the highest point of the domed back was only 55 feet below the River. The flooding took no lives. In other respects, however, it might be difficult to find in mining lore o more savage example of the application of "Murphy's Laws".

Jan 1, 1968

By Mark Van Dyke, Ted Klemetti, Jake Beale, Zoheir Khademian, Joe Wickline

In 2016, a 3.7-ML magnitude event caused by mining activity occurred at a longwall mine in southwestern Virginia which was recorded by the United States Geological Survey (USGS) and felt by local residents. The event was the largest of its kind since a global mine design change by the operator was instituted in 2008 following three large events in 2005, 2006 and 2007 (3.4, 4.3, and 3.4, respectively). Two of the three pre-2008 events (2005 and 2007) damaged ventilation controls in the mine which fueled a mine fire. In 2016 the mine’s management requested researchers from the National Institute for Occupational Safety and Health (NIOSH) to access geological data and determine what parameters could possibly lead to events of a magnitude of 1.0 ML or greater. Evaluation of 2,152 geological data points and modeling revealed three major geological factors in common with the majority

By Gamal Rashed, Tim Miller, Nicole Evanek

High horizontal stress has been identified as a critical factor affecting roof stability in underground mines, particularly when the immediate roof consists of weak or laminated rock. Numerical models were employed to better understand the influence of caprock thickness, cutting sequences, and the orientation of driving direction relative to maximum horizontal stress on roof stability in underground stone mines. These models were calibrated based on field observations of roof falls from the study mine. The findings of this study enhance our understanding of roof stability under high horizontal stress and contribute to reducing the risk of roof falls in underground stone mines.

Feb 1, 2025

By L. Widdifield, R. Riggle

"In today’s challenging mining environment the “Big Picture” (Caterpillar, 2013) approach to mining is often neglected. With haulage costs approaching up to 45 % of the overall mining costs, all too often the load-haul-dump- return cycle is not investigated in its completeness. This paper will discuss the aspects of taking the time to observe an operation from the “Big Picture” approach. In today’s mining business miners, engineers, trainers, supervisors, and managers have ever increasing roles and responsibilities as never seen before in the past decade. The endless human resource, safety, environmental, cost control issues and performance initiatives, detracts from precious time that may have been dedicated to examining the day to day operation. Having examined numerous mining operations over the past several years, one common denominator is lack of time to properly observe operating practices in the field and recognize both positive and negative observations. The old fashioned vocation of observing the operation to assess the haulage, loading and maintenance processes to adjust, maximize or enhance operations have sometimes vanished. Four areas to be discussed in this paper: (1) Look at the “Big Picture”(Caterpillar, 2013), (2) Use common sense, (3) Areas identified for biggest improvements in the operations, (4) Observation of small details for big impacts to lower cost per ton and increased production. The objective of this paper is to provide low cost recommendations to lower cost per ton and increase production. INTRODUCTION Whether miners claim to have been around and experienced it all or the “rookie” on the mine site, miners are expected to execute the mine plan at the lowest cost possible. So why is it so difficult to execute this task? Shouldn’t supervisors just have to man the equipment, tell operators to have a safe day and tally up the numbers at the end of the shift? And let the technology system do the rest? So what could go wrong? Lots. Mining companies seek help from consultants, training departments, performance reporting systems and an arsenal of resources. Armed with all this information, the supervisors just hop in the pick-up and tell the shovel operator to speed up. Sounds simple enough. When the improvements don’t happen, what could have gone wrong? It comes down to people, the simple things that were not executed over the months previously and as a result today the mines performance is not where it should be. A mine is built by people. Managers who have the vision to develop the ore body in a manner that follows sound engineering practices. The infrastructure to mill the ore and support the equipment needed to move the material. Along the way equipment is procured and operators trained to run the gear. Engineers and geologists set up the design, the material movement, and haulage routes. Sounds easy to this point. So, why mine after mine is there this constant struggle to move more with less and get the costs down? Understanding how to make “Great Miners” out of these people is critical to lowering your cost per ton."

Jan 1, 2016

By P. Karimi, A. Akcil, A. Amini, H. Abdollahi

"In this study, cyanidation experiments were carried out on a massive sulfide ore sample, whose grades of the precious metals gold and silver were found to be 4.2 g/t and 311.9 g/t, respectively. Other elements in the ore were arsenic with average grade of 1,751.6 g/t; antimony, 619.7 g/t; zinc, 781.4 g/t; copper, 454.6 g/t; lead, 101.8 g/t; mercury, 324.3 g/t; and bismuth, 0.6 g/t. The first objective of test work focused on determining the best conditions for extracting gold from the ore, ground to less than 75 microns. Different influential parameters such as particle size fraction, cyanide concentration, pH and leaching time were investigated. The optimum parameters were found to be particle size fraction of less than 25 microns, cyanide concentration of 2,000 mg/L, pH of 11 and cyanidation time of 24 hours. In these optimum conditions, the highest gold and silver leaching efficiencies were 76.88 and 59.63 percent, respectively. In addition, roasting as pretreatment at a temperature of 700°C over a period of two hours was evaluated. Cyanidation testing of the roasted ore in the optimum conditions found increases in the gold and silver leaching efficiencies to 85.97 and 67.57 percent, respectively. Moreover, antimony extraction rose to 43.10 percent, from 23.73 percent without roasting.IntroductionGenerally, gold ores can be classified as “free milling” or “refractory,” depending on how they respond to cyanide leaching (La Brooy et al., 1994; Celep et al., 2009). While high gold recoveries (> 90 percent) from free-milling gold ores can be readily achieved, refractory gold ores are often characterized by low gold recoveries (50-80 percent) within a conventional cyanide leaching process (Rubisov et al., 1996; Adams, 2005; Celep et al., 2009). The presence of preg-robber components such as carbonaceous matter, sulfide minerals and aluminosilicate can further decrease gold and silver dissolution rates and recoveries. With the negative effect of the presence of preg-robbers, gold dissolution is considerably diminished in solutions with high cyanide concentration (Tan et al., 2005). In such refractory gold ores, gold particles may sometimes be occluded or included in the sulfide minerals, and pretreatment becomes necessary to break down the mineral structure to liberate gold for subsequent recovery. These ores are usually pretreated with an oxidizing process, after which gold and silver can be recovered by a standard cyanidation process. The main oxidizing processes available for refractory gold ores are roasting (LaBrooy et al., 1994; Angelidis and Kydros, 1995; Li et al., 2009; Karimi et al., 2010; Kyle et al., 2012), biological oxidation (Lawrence and Bruynesteyn, 1983; Komnitsas and Pooley, 1990, 1991; Deng and Liao, 2002; Ciftci and Akcil, 2010, 2013) and pressure oxidation (Mason, 1990; Murthy et al., 1992; Qingcui et al., 2009). In addition, ultra-fine grinding is being used in some plants for the liberation of gold and silver particles that are interlocked in the sulfide or silicate minerals (Celep et al., 2011)"

Jan 1, 2015

By E. A. Sondreal

Requirements of flue gas desulfurization (FGD) for Eastern and Western U.S. coals will not be the same because of differences in coal sulfur content, ash analysis, and beating value. The effects of these differences and of limited availability of water in the West are the subjects of this paper. Eastern and Central bituminous coals are generally high in sulfur and require removal efficiencies in the range of 70 to 90 percent to meet the Federal emission standard of 1.2 lb SO2/MMBtu. Ash in Eastern coals is low in alkali content and is relatively insoluble in scrubber solutions. High sulfur content and market availability make salable product methods more attractive in the fast and Central United States than in the West. Western subbituminous coals and lignites are generally low in sulfur content, however, only a few deposits could reliably meet the Federal emission standard without FGD, Required removal efficiencies generally fall in the range of 0 to 60 percent to meet the 1.2 lb SO2/MMBtu limit. If the standard were raised to 2 lb S02/MMBtu, approximately two-thirds of Western coals could be burned without FGD. Some Western coals contain ash high in alkali, some of which is soluble in scrubber solutions. This complicates scrubber chemistry, but it also provides the meant for displacing some or all of the limestone requirements when only moderate S02 removal is required. Dry areas in the West would benefit from full commercial developement of dry processes of FGD.

Jan 1, 1974

By D. R. Spears

The Bureau of Mines has investigated the fundamental aspects of shear-flocculation using a rapid, in-situ particle size analyzer. Silica was stirred in the presence of an aliphatic amine to determine the effects of collector coverage, stirring speed, and solids concentration on the kinetics of shear-flocculation. The results showed that shear-flocculation is a two-stage process. In the first stage, mean particle size increased rapidly in the first 1-2 min of reaction; in the second stage, an equilibrium was set up between the rate of floc growth and floc decay. Collector dosage affected the position of the equilibrium by altering the number of surface sites for particle-particle attachment. A minimum stirring speed was necessary for shear-flocculation to occur and was dependent on solids concentration and collector dosage. This speed was the minimum necessary for particles to overcome the electrostatic energy barrier which kept conditioned particles dispersed. Larger particles flocculated more rapidly. At very high stirring speeds, large flocs became unstable, resulting in a narrowed particle size distribution in the slurry.

Jan 1, 1993

By Furuyama Takashi, Mori Sukeyuki, Hara Tsuyoshi, Fukushima Yujin

In mineral processing practice, flocculation is largely established as an engineering technique of waste water treatment and the study of parameters increasing the settling velocity of particles is still of great importance to improve the process. Further investigations were made using quartz (Q89) and fluorite samples (F91) which included 58.8% and 65.8% of -2.3 µm particles respectively. In all the experiments the flocculation phenomena were observed varying the pH value of the aqueous suspension. In contrast to quartz particles (Q89) which did not flocculate for all pH values, it was, noticed that fluorite particles (F91) flocculated in the alkaline range of pH over 11. With an aqueous suspension containing equal quantities of Q89 and F91, a hetero-flocculation of particles was observed at a range of pH below 10. In this case, the maximum floc size of the hetero-flocculation was 37.0-26.2 µm This size was about three times larger than when quartz (Q84) and fluorite particles (F85) were used with 32.4% and 40.4% of -2.31 µm particles respectively. Besides, in the experiments using Q89 and F91, the maximum size of hetero-flocculated single particles was found to be 6.54 µm instead of 3.27 µm as obtained with Q84 and F85.

Jan 1, 1995

By Yuting Xue, Khaled Mohamed

The failure of coal ribs is a major hazard in underground coal mines. Researchers from the National Institute for Occupational Safety and Health (NIOSH) have been working on the development of an engineering-based rib control method. A user-friendly standalone application, called Design of Rib Support (DORS), is being developed to ease the calculations of rib support. DORS can estimate the Primary Rib Support Density (PRSD, ton/ft2) for development loading. However, it still needs to take account of another key factor, bolt length, in rib support design. The bolt length can be estimated from the rib fracture depth, and this study focuses on the coal rib fracture depth analysis with numerical modeling and artificial neural network. A total of 331 FLAC3D simulations with different mining scenarios and rib conditions were conducted for this study. Machine learning was then used to predict coal rib fracture depth under different conditions. Based on the numerical simulations, the parameters for mining scenarios and rib conditions were collected as features for machine learning, and coal rib fracture depths were collected as the target to predict. Good data correlation (r-square) was obtained with the use of an artificial neural network. The

By H. Habenicht, E. Urschitz

Three mining methods for full extraction in flat coal seams - i.e., longwall (L W), shortwall (SW), and rib pillar extraction (RPE) - are com- pared with each other in view of the introduction of a mechanized, self-advancing roof support. Features are shown according to which RPE appears most attractive under certain conditions. In this presentation, the mining methods are outlined and discussed. The new support (Alpine Breaker Line Support, ABLS) is described, and its employment is explained. A trial operation in RPE using the ABLS has been conducted successfully in a South African coal mine. The results and improvements are stated.

Jan 1, 1988

By R. B. Hopler

Explosives R&D has historically been motivated by coal mining. Whether to solve safety problems or to improve productivity and cost, the result has been the same: better explosives products and initiation systems. This process continues at an accelerated pace today due to the tools presently available to the explosives and mining industries.

Jan 1, 1993

By David X. Zhang

This paper describes the results of using shear flocculation and flotation known as aggregative flotation technique for the enrichment of coal-derived char produced from mild gasification process. Aggregative flotation is a separation process which involves the use of suitable aggregating liquid under the action of high shear forces to render hydrophobic surface of coal-derived char particles to aggregate in an aqueous slurry. The fine carbonaceous particles are aggregated into larger floes while the impurities remain hydrophilic. In subsequent flotation process, the char aggregates are then separated from mineral matters by aeration in the flotation cell. The floatability of char aggregates and removal of mineral matters from chars are studied in a lab scale flotation column cell. The effect of various operating parameters on the aggregative flotation responses is presented. Emulsification of aggregating liquid using high intensity agitation and ultrasonic energy provides excellent aggregating liquid dispersion and increases selectivity for char aggregation. In subsequent flotation process, it results in significantly increasing the flotation rate of char aggregates. The microscopic examinations of bubble attachment to coal-derived char particles under various aggregating liquid dispersion levels were conducted by induction time measurement. The distributions of hydrophobicity of char particles and char aggregates prepared under various aggregating liquid dispersion techniques were measured by film flotation. The char particles prepared under high intensity emulsification attach at significantly faster rates to air bubble and with lower mean critical wetting surface tension than that of char with direct aggregating liquid addition. An interrelationship of increasing in flotation rate/combustible recovery with decreasing in induction time, mean critical wetting surface tension and dispersion of hydrophobicity on the char particles and char aggregates were obtained.

Jan 1, 1992

By C. J. Newman

Prior to 1995, the smelting process at the Kennecott Utah Copper Corporation (KUCC) smelter consisted of Noranda reactors and Pierce-Smith converters. In the consideration of expansion opportunities, the existing process did not lend itself to a program geared towards processing the total output of KUCC mining and milling operations. During 1989 and 1990, a number of smelting options were evaluated. The final selection was the Outokumpu flash smelting process, coupled with the new Kennecott-Outokumpu flash converting technology. Facilities were designed and installed to process 1.0 million tonnes per year of copper concentrate, with the ability to expand to 1.2 million tonnes per year. Following the shutdown of the smelter facility utilizing the Noranda technology in May 1995, the flash smelting furnace commenced operation in June with the flash converting furnace startup following a few weeks later. The smelter has achieved design production targets and environmental goals. Current operating rates are at or above design rates for concentrate and matte processing. Emissions are lower than the permit levels and equate to less than 3.5 kg of S02 per tonne of copper. This paper outlines the design, construction, startup and the first two years of operation of the modernized KUCC smelter.

Jan 1, 1998

By Jim McKinley

With a growing number of mines reaching closure and seeing closure costs materialize, regulators, lenders, and banks are observing projects that fail economically by miscalculating these costs. Mine closure costs are often categorized as a type of liability which is defined as the money owed by the company to offset effects from the project, and the money available to pay for those debts (e.g., bond). Often, decisions made before Day 1 of mining (e.g., co-disposal, dry stack tailings, waste segregation) can significantly change the bond calculation. Once the bond is calculated and funded, operators are encouraged to conduct closure research and use applied science for progressive bond release prior to final closure. However, this author has observed few instances of financially significant progressive bond release, as there are typically no robust procedures for bond return, either before or during closure activities. As a result, many companies decide that entering a state of Care & Maintenance (C&M) is less risky than attempting to fund closure activities with an unknown bond return mechanism. Although perhaps less risky in the short-term, the primary long-term risk with entering C&M is that it increases the chances of the bond not covering the cost of closure and the chances of the government/regulatory agency inheriting the mine closure. Bonds are typically reevaluated on a regular cycle (e.g., five years) so every mining company goes through this financing challenge eventually.

Feb 22, 2026

By Eric Gilmore, Ron Tudor, Gregory E. Korbin, Bill McCormick, Brad Bush

INTRODUCTION Las Vegas has recently been termed the “Construction Capital of the Country”. It has also been acknowledged as the fastest growing city in the country for several years running. The rapid growth improves the economic picture of the region but it also imparts unusual demands on the area’s infrastructure. In 1994 the Southern Nevada Water Authority (SNWA)was working on a master plan to address the rapid growth. A long range analysis revealed the need for additional water treatment capacity and delivery systems. Short term projections showed that the current system would reach capacity in the summer of 1997 with the possibility of demand exceeding the supply. The River Mountains Tunnel #2 is part of a $150M scheme to quickly upgrade the system to meet the short term demand, improve the overall system operation and allow for a smooth transition into the larger additions being planned for the future. The SNWA selected Carollo/Black & Veatch (CBV) to provide detailed design and construction management for the upgrades. The River Mountains Contracts consisted of five separate contracts broken out separately to stream line a very aggressive (just 34 months) design and construction schedule. Necessary work included four miles of excavated and lined tunnel, connections from existing pipelines to and from the new tunnel including large diameter (to 3.66m(144 in)) valves, a 18 927cu m (5 million gal) regulating reservoir, a surge tank and a 170 343cu m (45 million gal) reservoir to add additional storage to the system. Notice to Proceed was given to Kajima Engineering and Construction (Kajima) on May22, 1995 for the construction of the River Mountains Tunnel #2. The design called for a tunnel to be driven 6070m (19 915ft) in rock and lined to a finished diameter of 3.71m (12.17ft).Excavation began on December 14, 1995 and holed through on April 30, 1996. Lining began on June 25, 1996 and a notice of Substantial Completion was issued on December 13,1996. This paper describes the measures taken to complete the tunnel in 18 months from Notice to Proceed to Substantial Completion. THE RIVER MOUNTAINS SITE The River Mountains are a low range of rugged mountains separating the Las Vegas Valley from its main supply of water, the Colorado River at Lake Mead. They are volcanic in origin and the harsh desert environment has left them as expanses of exposed bedrock rising 305m (1000ft) above the valley with little or no vegetation. An existing 3.05m (10ft)

Jan 1, 1997

By R. A. Ynchausti

In January 1993, Pyramid Resources began implementation of a supervisory expert control system at a U.S Cu concentrator. The objective of this control system was to improve plant profitability through unit operation optimization and integration. This paper documents the key aspects of the project, including: economic and associated benefits, system architecture, concepts of implementation, process control strategies, practical aspects of implementation and conclusions. The implementation of expert control at this concentrator has resulted in an estimated benefit of $50,500 per day. This is a net result of improved tonnage, reduced reagent consumption, improved concentrate grade and reduced energy per ton produced.

Jan 1, 1995

By K. F. Unrug

Extrapolation of the rock properties obtained from the cores exploration holes to the surrounding areas often causes problems because of frequent sudden changes in the geologic composition of strata. To address this problem, the author has been developing a method of rapid strength testing "in situ," with application of a borehole penetrometer. This method, as opposed to conventional laboratory testing, does not require rock samples to be retrieved and handled/machined before testing. The results are generated by strength determination on the wall of a drill hole at a site. The newest development is a borehole penetrometer that requires only a 1.38.mm (1.5 in) diameter hole. The small diameter of the penetrometer body allows for drilling test holes with production mine equipment such as roof bolters. It opens the possibility of broad application in coal mines, as well as in hard rock mines and tunneling. The principles of the apparatus are described and are illustrated with examples of its applications.

Jan 1, 1999