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By Brianna Eiter, Max Barham, Tim Bauerle

While not well established, there is evidence that the mining industry is encumbered by several work-related fatigue risk factors. Compared to other industries, mine workers are more likely to report inadequate sleep and work longer hours per day. Given these observations, there is a critical need to identify effective ways to intervene, manage, and mitigate mine worker fatigue and sleepiness when present. One barrier to this is confusion around the similarities and differences between fatigue and sleepiness, which can result in these terms being treated as interchangeable regardless of context and make it difficult to assess and mitigate safety risk.

May 1, 2024

By David M. Abbott

"The picture of the baby surrounded by the number of (usually) pounds of a variety of mineral products a newborn will use in a lifetime has been widely distributed over the years, both on the web and as business cards that could be distributed to anyone. Figure 1 shows a typical example. I have included a slide of the mineral baby in various lectures over the years, particularly in my lecture “Industrial minerals: much used, little recognized.” The mineral baby with associated estimated lifetime mineral quantities is updated every year. I collected a set of past mineral baby pictures to examine the changes in the quantities of the various mineral products over the years.The mineral baby was introduced by the Minerals Information Institute (MII) in 1999 and became known as the “MII Baby.” SME took over MII in 2008 and continued publication as the “MII Baby” until the merger of MII with SME’s GEM program in 2011 to form SME’s Minerals Education Coalition (MEC). MEC is now the publisher. Figure 2 is the 2016 version of the mineral baby. The repositioning of the picture of the baby from lying on its back to crawling reflects a major design change to help emphasize that SME’s MEC is now the mineral baby’s publisher.Data sourcesThe data used to prepare each year’s mineral baby comes from the National Mining Association, which collects the preliminary annual mineral commodity data from the U.S. Geological Survey (USGS) and other sources. This preliminary data becomes available late in the first half of each year. The life expectancy data for each year comes from the Center for Disease Control’s “Data and Statistics by Topic” and the population data comes from the U.S. Census Bureau’s “Quick Facts” tab.The source mineral data is compiled using metric tonnes as the basic unit. The quantity of of each mineral is the apparent U.S. consumption each year."

Jan 6, 2017

By Mike Moody

"No matter what type of ore is being extracted from a mine, mucking with front loaders can be accompanied by wet fines that cling to every surface. Once loaded into a hopper or conveyer transfer chute, viscous material can quickly build up on the walls to create bottlenecks, clogging the chute and causing expensive downtime.Clearing material from hoppers, chutes, bins and vessels can be done using manpower and tools on hand, but safety experts recommend considering a solution that prevents exposing workers to potential hazards. Operators at modern mining sites, such as the Eagle Mine, located in Western Marquette County of Michigan’s Upper Peninsula, understand that using specialized equipment reduces worker exposure, offers the safest mode of production and provides the most cost-effective lasting results.“Safety is a top priority for us,” said Ted Lakomowski, lead reliability technician at the Eagle Mine. “When we experienced clogging and downtime at the processing mill, the crew naturally swung into action to resolve it, but we immediately sought a safer long-term solution.”Stope mining for nickel and copperOwned by Lundin Mining, a globally diversified base metals mining company headquartered in Toronto, ON, Canada, the Eagle Mine is the only primary nickel mine in the United States, producing 1.5 percent of the world’s total nickel production. The first operation permitted under Michigan’s Part 632 Non-Ferrous Mineral Mining Law, it opened in 2014 and is expected to produce 163 kt (360 million lbs) of nickel, 134 kt (295 million lbs) of copper and small amounts of other metals over its estimated nine-year lifespan.The company extracts approximately 2 kt/d (2,200 stpd) from the underground nickelcopper mine using a bench-and-fill stoping process. Accessed from the surface by specialized underground trucks, the vehicles carry about 45,400-kg (100,000-lb) loads through a 1.6-km (1- mile) long and 5.4-m (18-ft) diameter ramp shaft descending into the earth at a 13 percent grade. Stoping is a bottom-up method that involves systematically blasting columns of loosened ore that is then mucked by front loaders into trucks and backfilled using cemented and uncemented rockfill."

Aug 1, 2019

"Above ground, elevated belt conveyors with span >200m between support points can cross valleys, rivers, forests and buildings with minimal footprint. The Cable Bridge Conveyor is a new type of suspension bridge based belt conveyor system that has long span between support points. It combines typical belt conveyor and the improved simple suspension bridge to form a conveyor bridge. The improved simple suspension bridge places a widened bridge deck directly on suspended cables, without the need for high truss towers. The benefits include reduced cost and increase aerodynamic stability compared to conventional suspension bridges. The Cable Bridge Conveyor’s compatibility with current belt conveyors allows the versatility in application. INTRODUCTION Belt conveyor is a ubiquitous material handling system. Conveyors can be placed directly on ground or elevated above ground by support structures. Considerations of cost, design, environment, civil work, safety and process requirements are all factors in choosing the ground based or elevated conveyors (1). The ground based conveyor has the lowest structural cost, where the conveyor is laying on an existing road. Maintenance access is easy and straight forward. Compared to the ground based conveyor, the elevated conveyor can cross existing buildings and structures, give passage to traffic beneath the conveyor, has smaller footprint, and requires less civil work to pass mountainous areas. The drawback of the elevated conveyor is higher structural cost, which can be compared with savings in civil work and other benefits. Conventional elevated conveyors are supported by rigid truss type structures, with typical span of 15m to 25m between concrete support bents or steel trestles. Triangular truss, using steel pipes instead of hot rolled steel sections, is more efficient. The typical span of triangular truss supported conveyor is around 30m to 40m, while the weight is about 10% less than conventional box truss with shorter span (2). Long span elevated structure based on suspension bridge is another step forward in increasing the distance between support bents, reaching 100m~400m and beyond. The very wide distance between support points of an elevated conveyor offers unique benefits. The conveyor can cross rivers, valleys, highways, forests and other obstacles with minimal footprint and reduced civil work. The versatility from long span conveyors makes bulk material transportation over previously impossible terrains now a feasible option."

Jan 1, 2015

By Yi Luo, Jian Yang, YUJIA LIAN

Scale physical models, constructed according to the principle of similarity theory, are widely used to simulate the mining disturbances to surrounding strata and to evaluate the effectiveness of implemented ground-control techniques. This technique has also been used for studying mining-induced surface and subsurface subsidence. The movements of the observation points installed on the physical model at different mining stages are currently measured using a total station, which is time consuming and inaccurate, especially on small-scale models.

By VASU GANGRADE

Large-opening underground stone mines pose significant ground control challenges, including the risk of massive pillar collapses. These collapses can result in dangerous air blasts characterized by tremendous force and high velocity. Estimating the velocity of these air blasts proves challenging due to the absence of accurate air velocity instruments near the mine portals. To address this issue, this paper proposes a novel approach that leverages closed-circuit television camera footage from the mine. Specifically, it employs the optical flow algorithm implemented in Python to estimate the velocity of the air blasts, providing a valuable tool for assessing and mitigating risks in such mining environments.

Feb 1, 2024

Newmont Mining Corp. has been producing gold from the Carlin Trend for more than 45 years. Naturally, the focus, scale and complexity of the operations have changed considerably during this time. Newmont discovered and developed the Carlin Main orebody that is located about 32 km (20 miles) north of Carlin, NV. The property was developed as a one-mine, one-gold mill treatment plant operation, which produced about 6.2 t/a (200,000 oz/year) of doré gold bars. The initial mine, mill and gold refining facilities were relatively small in comparison to today?s standards. The milling circuit used the Merrill-Crowe zinc precipitation process to recover dissolved gold and prepare a concentrated precious metal ?precipitate? to be melted into a doré bar for sale.

Jan 1, 2012

By Ewan Alexander

"As human beings, we have managed risk since the dawn of the ages and have been adept at doing so. In order to survive, we hunted or gathered. If we did not take enough risk, we died. If we took much risk, we died (Fig. 1). As individuals and tribes, risk had to be optimized to maximize our chances to thrive, as individuals and as tribes.In today’s world, the risks are vastly different, but in order to thrive, these must be managed. And no industry knows this as much as mining. In fact, the International Council of Mining & Metals (ICMM) has proposed the Critical Risk Model (Fig. 2) as a means of identifying critical risk, critical controls and associated performance standards. The ICMM focuses on sustainable development performance in the mining and metals industry. It has 23 members, representing some of the largest mining companies in the world.This approach is going to help the mining industry. But it must be applied effectively, with the acknowledgment that the system alone cannot be effective. We can say this confidently, as even companies known for the strength of their risk and safety management systems continue to experience significant incidents, and, in some cases, catastrophes. Why does that happen when all safety metrics, including injury rate, are pointing in the right direction? In the view of the author, it is only when leadership, culture and systems work in complete harmony that the resilience of an organization to manage its significant risk is at an optimal level. It remains an ongoing leadership challenge to maintain that balance and the optimal mindset in the organization. So how do you maintain that special balance?Let’s start with a basic premise. Leadership, supported by simple effective systems, creates culture which creates outcomes. Everyone going home safely is an outcome, as is cost effective operations, and to achieve those outcomes efficiently, the organization must focus on the inputs. And those inputs include effective leadership, effective systems (for the purposes of this article, risk and health, safety and environment (HSE) systems), good planning, stable operations and competent workers. This article will focus on gaining maximum performance from your risk management system."

Oct 1, 2016

By N. Ward

The Gualcamayo Mine is located in the Andes Mountains north of San Juan, Argentina (Fig. 1). A property of Yamana Gold Inc., it declared commercial production in July 2009 and has a total mineral reserve and resource base of approximately 88 t (3.1 million oz) of gold. Crushing operations for the openpit mine are located in a 13,500-m3 (477,000-cu ft) underground cavern with a ceiling height of 22 m (72 ft). More than 3,600 m (11,800 ft) of tunnels are used to access the cavern and convey the ore. The project as described in this paper relates to the design and construction of the main cavern, conveyor system exit tunnel, the mechanical system access tunnels and two 4.2-m- (13.7-ft-) diameter shafts (Ore Pass #1 and Ore Pass #2) (Fig. 2). Preliminary engineering for the project was performed by Hatch Chile. Rizzo Associates Argentina, S.A., a division of Paul C. Rizzo Associates, Inc. (Rizzo), was contracted to provide geomechanical and geotechnical support for the construction of the access tunnel system and geomechanical design and construction supervision for the cavern and shafts.

Jan 1, 2011

By Nikolaos Syrtariotis, Mark Berger, Timothy O’Brien, Vojtech Gall

The Northeast Corridor Superconducting Maglev Project (SCMAGLEV) entails construction of a high-speed train system between Washington, DC and New York City, with the first leg between Washington and Baltimore, MD. This innovative project will shorten travel times between Washington DC and Baltimore to approximately 15 minutes, and connect Washington, DC to New York City in under an hour. In 2021 the draft EIS is expected to be issued for comment with a Final EIS/ROD anticipated by early 2022. This paper provides an update on the project as presented in Gall et al. (2020) and discusses the economic and environmental benefits, preferred alignment alternative, preliminary staging and launching of the TBMs for construction, and preliminary station design.

Jun 13, 2021

By D. M. S. Bhatia

Twenty-six insitu analyses of cubic galena crystals from a Mississippi Valley-type deposit were undertaken with a laser microprobe spectrograph to study the variation of nine trace elements from the crystal center to its periphery, both along the diagonal and vertical. The general trend is an increase in the concentrations of Ag, Ga, Ge, and In with As showing the opposite trend Bi, Cd and Sn did not show any pattern. Sb was not detected. These variation patterns nay serve as a model for similar studies of other Mississippi Valley-type deposits.

Jan 1, 1984

By J. Chai, Q. Yuan, B. Qiu

"Overburden strata deformation monitoring is one of the key problems in ground control. Using geophysical method through surface drilling to detect strata deformation is commonly used in the industry. In this paper, a geophysical method based on the distributed optical fiber sensing (DOFS) system were conducted in the laboratory, where a DOFS-based strata deformation monitoring experiment was performed with three physical models. The results show that the DOFS method precisely detects the rock mass deformation and strata structure forming with the Brillouin frequency shifts (BFS) representation. The BFS curves are divided into three phases, which reflects the horizontal three zones developed in the overburden. The BFS distribution presents a multiple stages form, the 1st stage corresponds to the caving zone and the 2nd stage corresponds to the fracture zone. Based on the multiple stages form, the evolution of the water flowing through fractured zone have been determined and the controlling effect of key strata over the water flowing fracture has been pointed out. In the end, the comparison validation proves the accuracy and reliability of this method, and it could be a new approach for the ground control research. INTRODUCTION Overburden rock strata above the work face space will propagate from slight deformation, part destruction to violent movement because of the underground coal mining. It is fundamental and an intrinsic requirement of ground control to monitor the mining-induced rock mass deformation.[1] Overburden strata have their significant mechanical behaviors and movement under damage deformation and fracture. Overburden strata deformation affect the mining ground pressure control directly, and performance in the relationship of supporting equipment and the surrounding rock, the mining-induced fracture distribution and the loss of underground water resource, the ground surface structure stability and the ecological environment.[2] From the perspective of the concept of safe and efficient scientific coal mining: the overburden strata deformation is an important part of mining method selection and reasonable supporting solutions decision which can solve the issues like the roof supporting force calculation, overburden fracture distribution and gas drainage, ground subsidence, separation of coal and rock control and top-coal recovery rate and so on. From the perspective of green and ecological mining: the overburden strata deformation is the key basis of studying the mining-induced ground subsidence and mining area ecological damage, and such engineering problem like environmental protection in mining area, ecological restoration in mining subsided land and the water conservation in fragile ecology area of mining could be solved based on it.[3-6] Therefore, the mining-induced overburden strata deformation is the key of ground control and needs to be controlled artificially."

Jan 1, 2017

By Brij M. Moudgil

Flotation of fine and coarse coal after multistage addition of the frother was found to yield coal fractions with significantly lower ash content as compared to the feed. It was observed that the lowest ash content, specific gravity and reactivity of coal was associated with finer size fractions. Ignition and combustion characteristics of different coal fractions were evaluated using a differential thermal analyzer (DTA) with calorimeter attachment. It is suggested that in the ignition stage, the removal of mineral matter affects the reactivity through the physical changes brought about by the ash removal. In the char combustion stage the mineral matter seems to influence the reactivity through the catalytic activity of surface concentrations of metal ions, ratio of combustible/incombustible material, internal pore structure and roughness.

Jan 1, 1984

By H. M. Park

Risk is a major factor in all mining activities, arising from many internal and external variables. The authors? research has resulted in a systematic method for the quantification of risk in mining projects (Park, 2012). This is the second part of a three-part series. The first part was published in the October 2013 issue of Minining Engineering magazine and can be found here at www.me.smenet.org. This paper discusses methods of assessing the overall risk associated with those variables, and presents a statistical model based on a survey of 31 experts. The third paper, to be publised at www.me.smenet.org on Oct. 14, presents an evaluation of the statistical model, using data from previous mining investment decisions in which the authors have been involved.

Oct 1, 2013

By R. Mathur

Cu isotope fractionation in low-temperature aqueous environments has been well documented. Here Cu fractionation was applied to two distinct, yet related, mining problems. First, an exploration geology application, where copper isotope fractionation was measured in oxidized leach caps, chalcocite enrichment blankets and hypogene mineralization in three porphyry copper deposits located in the southwestern U.S. Cu isotope patterns exist in a vertical distribution within the mines, coupled with distinct relationships with the Cu grade. Second, a hydrometallurgical application, where copper isotope fractionation was measured in leach fluids, feed and residues from a quick leach test (QLT) on Cañariaco, Peru ores. The results indicate the relative proportions of the minerals providing Cu during leaching. Interpretations of the QLT test measurements indicate covellite is the dominant ore mineral providing Cu during leaching. Both applications clearly demonstrate the use of the Cu isotope technique to understand low-temperature aqueous processes involving copper.

Jan 1, 2012

By Robert E. Mclvor

Classification system efficiency (CSE) is a simple metric that can be used to measure and increase ball milling circuit efficiency. It is defined as the percentage of the ball mill energy being used to grind target (oversize) particles. This paper describes CSE analysis conducted for a variety of operations with related improvements in circuit efficiency ranging from 3 to 30 percent. The achievable CSE for any given ball milling circuit is described, providing the means to determine the extent to which every plant can benefit from increasing grinding circuit CSE.

By Yi Luo

Simulation of the multi-entry and multi-crosscut (MEMC) ventilation systems commonly employed in U .S. underground coal mines can be very tedious, due to the large number of crosscuts with stoppings to be represented in the network models. In order to reduce the amount of work needed to build the models, a common practice is to represent a number of crosscuts with one equivalent airway. However, this introduces certain errors into the simulation results. In this paper, algorithms have been proposed to simplify the ventilation networks of common MEMC systems encountered in panel development operations. The algorithms can be used to reduce a MEMC system into one airway with an equivalent resistance and to determine the airflow distributions in the system and the leakages through the stoppings.

Jan 1, 2011

By Jerry C. Tien

The rare earth elements (REEs) are a group of 17 chemical (metallic) elements which appear in the periodic table. The group consists of 15 lanthanide elements along with yttrium and scandium (Table 1). They share many similar properties, which is why they occur together in geological deposits. Although commonly referred to as rare, they are really quite common; the reason they are perceived as rare is because it is not common to find them in commercially viable concentrations. These metals are critical to advanced technology, ranging from smart phones to global positions system (GPS) receivers, medical devices and jet engines. They are critical in green, high-tech and defense industries (Fig.1 and 2). Although there have been increasing efforts to find alternative supplies, these efforts have been complicated by the pollution that rare earth mining and processing creates. To extract rare earths minerals from mined ore is a complicated and costly process. The ore is first mined through normal mining process, the bastnaesite, which generally contains a number of minerals of little value, is first removed through a floatation process. The bastnaesite containing the REEs is further separated into their respective pure forms in a separation plant using acid and various solvent extraction separation steps. Each element has its own unique extraction steps and chemical processes. At times, these elements, in the form of oxides, will require reprocessing to achieve ideal purity. The last steps would be to further process into metals first, then alloys for various applications. The entire process takes approximately 10 days. The mining and processing of REEs, if not carefully controlled, can create environmental hazards. This is one of the reasons the Mountain Pass Mine in California was closed down in the 1980s.

Dec 1, 2013

By Richard Giffen, Michael Trabold, Pablo Lemus

"As part of the new 2nd Ave Subway Project, an existing tunnel constructed in the 1970’s will be connected to the new subway and used as new running tunnels. The existing tunnel had to be modified to comply with newer structural and fire life safety codes and to be connected to the new cut and cover station at 96th St. This paper will discuss the complexities of tying an existing tunnel constructed over 40 years ago into the new station and allowing for movements due to the unloading of the existing tunnel and the differential settlement of the two structures during both the construction and permanent condition. Topics that will be discussed include structural analysis, ground improvement techniques, selection of support of excavation walls, working in contaminated soil and instrumentation and monitoring of the structures. It will also cover retrofitting the tunnel to comply with updated Fire/Life/Safety requirements. PROJECT OVERVIEW The Second Avenue Subway (SAS) will be the first major expansion of New York’s subway system in over 50 years. To be constructed in four phases, it will run from 125th St. in Harlem to Hanover Square in the Financial District (see Figure 1). For most of its length, the alignment is directly under the Second Avenue roadway."

Jan 1, 2016

By Roger Storry, Arnaud Hochart, David Harris, Olivier Martin

"INTRODUCTIONThe Port of Miami Tunnel (POMT), designed and constructed by Bouygues Civil Works Florida between 2009 and 2014, was a Public Private Partnership between the Miami Access Tunnel Concessionaire, Florida Department of Transport, Miami-Dade County and the City of Miami. The project comprises dual 11.3m internal diameter, 1.27km long, twin lane road tunnels running between Watson and Dodge islands under the main shipping channel in Biscayne Bay. Five cross passages (CPs), spaced at 200m centre to centre, provide emergency access between the two tunnels, as shown in Figure 1.The CPs were constructed by open-face excavation methods but the particular geological conditions at the project site (loose and variable carbonate sedimentary strata with very high permeability) required specific ground treatment solutions to provide safe excavation conditions and to ensure the long term serviceability of the permanent works construction. Where access allowed, ground treatment was performed from the ground surface using deep-mixing techniques; however, at two locations (CP2 and CP3) surface access was restricted and ground treatment by freezing, performed from the tunnels, was required. The CPs are 12.3m long with an excavation diameter of 5.8m and are located up to 30m below the water table partly or wholly within the Key Largo limestone (termed Layer S7 in the ground model). Layer S7 is a coralline limestone having a metastable honeycomb structure and high variable porosity. At CP2 the upper portion of the excavation was within the overlying Anastasia Formation limestone (Layer S6), comprising a highly permeable coquina. The geological profile along the project is shown in Figure 2.This paper presents aspects of the freeze design and the risk mitigation necessary to successfully achieve the construction of the CPs in the unique geological conditions."

Jan 1, 2016