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By Andrew J. Petruska, Austin F. Oltmanns

The paper proposes a capacitive load cell for detecting changes in material and tool wear conditions for conical picks used in underground mining. The current process is dangerous and subjective, relying on human operators near the cutting interface. The new sensor aims to improve worker safety by allowing operators to perform their functions from a greater distance.

Aug 1, 2023

By Lee W. Saperstien

At the heart of the mining process are a number of basic and fundamental tasks whose regular and repeated performance constitute the mining cycle. As will be discussed presently, these tasks are the basic components of the mining system. Section 9, Production Operations, provides the mine designer and engineer with an understanding of these tasks and with sufficient design principles to allow this person to create an efficient mine system. This section is meant to be an introduction and adjunct to subsequent sections that describe specific mining systems. However, sufficient design information is included here for the independent design of mine systems that may not be described elsewhere or for subsequent verification of existing designs. For the purposes of this section, mining subsumes excavation; thus this material applies to any excavation process. Accordingly, this section is written in general enough terms to include both surface and underground mining. It may be used also for civil engineering excavations that often involve the same steps. Obviously, the actual procedures undertaken in any specific mining system will appear to be very different from those taken in any other system. This is certainly true when comparing surface with underground methods. Yet the fundamental principles are often the same. This segment is written to explicate the basics. Wherever appropriate, the section will suggest the differences between the application process to surface or to underground mining.

Jan 1, 2008

By William Gleason

"It is the largest mining exhibition in the world that attracts thousands of attendees from around the world to Las Vegas, NV once every four years. Despite the recent struggles in the mining industry, MINExpo International 2016 promises to be as big as ever. In the following pages, Mining Engineering takes a look what some of the more than 1,800 companies plan to showcase during the three-day exhibition.CaterpillarCaterpillar will support MINExpo 2016 with an exhibit showcasing machines, technology, expertise and practical knowledge that miners can apply to help address their cost, productivity and efficiency challenges in today’s mining environment.Caterpillar will once again occupy the largest space at the event and will showcase both surface and underground machines, but the talk at the booth will focus on how Cat technology and know-how combines to help mining operations address and solve the issues that are most important to them. The main stage in the exhibit will feature presentations describing how mining companies, Cat dealers and Caterpillar work together to improve operations.“The challenge for all in the mining industry now is to optimize operations — to drive costs down while creating sustainable businesses that can weather downturns,” said Caterpillar Resource Industries group president Denise Johnson. “We believe that through our expertise and the knowledge of our dealers —combined with innovative technologies and our growing data analysis capabilities — we can help them not only survive, but thrive in these challenging times.” Johnson was selected by the National Mining Association (NMA) to chair MINExpo 2016. “Chairing this show is a great honor, and it’s a testament to Caterpillar’s partnership with this critical industry,” she said. “We’re proud to be a long-time supporter of the NMA, and we are excited to participate in another MINExpo. It’s an opportunity for us all to learn from each other how to increase productivity, control costs and improve overall operations.”Surface mining displays. The surface mining section of the Caterpillar exhibit will showcase the new MD6420C rotary drill. This is autonomy ready and optionally equipped to leverage the safety and productivity benefits of Cat MineStar Terrain. This high-precision drill management system optimizes utilization and improves drilling and blasting operations by accurately guiding the operator and improving precision of hole placement and drilling depth — and the next step is fully autonomous operation, Command for drilling. The third-generation drill incorporates proven Cat components throughout for superior reliability and durability."

Sep 1, 2016

By Alton G. Woody

Like so many installations of its type approaching middle age, the ore processing and shipping facilities in Puerto Ordaz, Venezuela, have taken a lot of twists and turns in their lifetime. The object of this paper is to lead you through these twists and turns and some of the reasoning for them. The need for additional sources of iron are in the United States became evident during the time of the second world war. An exploration team from U. S. Steel located further high quality direct shipping iron are in commercial quantities near Ciudad Bolivar, Venezuela in 1947. Basic decisions were made to develop these reserves for export via the Orinoco River through a new shipping port to be built at the confluence of the Orinoco and Caroni Rivers. The basic concept was for the ore to be loaded directly to ocean going vessels. This was something of a gamble since the basic economics depended upon successfully opening up the main channel of the Orinoco River to deepwater vessels, and the Bethlehem Steel mine in the same area was already working with shallow draft river boats and a transfer station on the coast. Always, the basic philosophy has tended to be to plan with expansion in mind. The original conveyor systems were 1.52 m (60 inches) wide with 200 idlers, whereas 1.07 m (42 inches) or 1.22 m (48 inches) wide conveyors could have carried any production foreseen at the time of installation. Stockpiles have been located and designed with room for expansion. Basic designs have had dotted line future expansion blocked in.

Jan 1, 1978

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

The conventional rare earth element (REE) industry has historically sought to develop ore deposits where geologic processes have produced mineralized zones with commercially attractive REE concentrations. These deposits are extremely uncommon, particularly in the USA. Given the criticality of these materials and the need for sustainable domestic supply, the current research seeks to leverage other autogenous processes that lead to concentrated REE resources. One such process is the generation of acid mine drainage (AMD). AMD is very common in many coal mining districts and results from the exposure and oxidation of pyrite during mining. During the generation and migration of AMD, liberated sulfuric acid mobilizes several metal ions including REEs. Treatment of AMD is required under U.S.C §1251, the Clean Water Act, and often consists of neutralization, oxidation, and metal hydroxide precipitation. To investigate the deportment of REEs during this process, a field sampling campaign was undertaken, whereby the concentration of REEs in AMD and AMD precipitates was measured directly. In the nine sites evaluated in this study, the REE concentrations of the precipitates varied from 29 to 1286 ppm with an average of 517 ppm among the sampled sites. The individual elements were enriched compared with the associated bulk Northern Appalachian (NAPP) coal material by factors ranging from 3 to 15. Furthermore, the distribution of REEs in all precipitate samples favored the heavy REEs (HREEs) when compared with traditional REE ores. This research represents the first part of multi-part research endeavor to characterize, classify, and determine the practicality of refining REEs from AMD and its by-products.

By John E. Appleby

Grupo Acera, HYLSA originated in 1942 when Hojalata y Lamina began operations to supply steel strip for the Cuauhtémoc Brewery, the parent company. Production began in April, 1943 with growth accelerated because of World War II. By 1948 the company was producing its own steel from electric furnaces charged with scrap iron. Further expansion was hampered by the fluctuations in availability, price and quality of scrap iron. As a result, a search was made for a suitable process to enable HYLSA to satisfy its need for a reliable source of feed for its steel-making facilities. Their relatively low iron requirements at the time did not justify the very high capital investments required using the conventional blast furnace method. Processes which by-passed the blast furnaces were very much in their infancy and were not commercially tested. HYLSA then undertook an investigation of the direct reduction processes, knowing full well that much larger companies in other countries had investigated several processes but their work had not established a trend toward direct reduction or any particular process. However, after much effort and persistence HYLSA arrived at a process which suited their conditions. By using Mexican iron ore and natural gas they developed the now well-known H. y L. Process to produce sponge iron. Concurrent with the start of investigations which led to the H. y L. Process, HYLSA began an exploration program for a suitable source of iron ore. Thus in 1951, Cia. Minera Las Encinas, S.A. was formed, culminating in the development of the ore bodies near Pihuamo in the State of Jalisco. Mining commenced and ore was

Jan 1, 1971

By L. L. Damon

A geochemical study of cyanide neutralization processes was conducted at Brohm Mining Corporation to gain a better understanding of the leach pad behavior and to develop a simplified procedure to quantify the attainment of compliance with permitted cyanide neutralization criteria. Such attainment is a prerequisite for off-loading spent ore from the leach pad at the "load/unload" gold heap leach operation. The geochemical study program consisted of size fraction analyses and weak acid dissociable (wad) cyanide analyses for various sections of the spent ore from the actual leach pad. Further testwork included size fraction analyses and wad cyanide analyses on the ore from four 29 foot laboratory test columns which were leached and neutralized with different neutralization treatments in parallel with an actual active leach pad. Wad cyanide was analyzed daily on the neutralizing columns and various parameters were monitored weekly on the influents and effluents during the leach cycle and neutralization period. A comparison was made of neutralized effluent chemistry and porewater extraction fluids, as well as an analysis of the selective adsorption of cyanide on various particle size fractions.

Jan 1, 1992

By Bill Mariucci, Gary Almeraris

All Rights Reserved. Printed in the United States of America. Information contained in this work has been obtained by SME, Inc. from sources believed to be reliable. However, neither SME nor its authors guarantee the accuracy or completeness of any information published herein, and neither SME nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that SME and its authors are supplying information but are not attempting to render engineering or other professional services. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Any statement or views presented here are those of individual authors and are not necessarily those of the SME. The mention of trade names for commercial products does not imply the approval or endorsement of SME.

Dec 1, 2009

By L. Adler

The valuable Maximum Utilization Factor (MUF) concept has been extended to other rotating excavators beyond stripping shovels and draglines. In this concept the boom reach and bucket capacity are multiplied to get an MUF, then normalized by dividing by the equipment weight. Statistical analyses were applied to the remaining shovels (hydraulic and cable), draglines, and backhoes. Positive correlations were found. Stripping shovels and draglines were also re-examined. The results provide an estimate of equipment diggability and encourage versatility by the interchange of the boom and the bucket. The concept further clarifies the existing equipment classification by delineating general excavating, loading, and stripping kinds. The results also forecast trends, and noted innovative advances and possible retrogression. Extension to other boom excavators, such as front-end loaders is recommended. The MUF concept provides one of the few indices of gross external characteristics available to the engineer-user of equipment.

Jan 1, 1990

By John M. Arnold

Several years ago it became apparent to some of our people that; there was developing a very definite need for largee coal reserves in the West to satisfy- the need for fuel for the furnaces of electric generating plants with the rapid development of, the West, of both population and industry, it was impossible for hydro-electrics plants to keep up with the ever increasing demand for electricity. In 1960, Mr. E. R. Phelps, then associated with the engineering department of Peabody Coal Company, began a search for and development of coal deposits in the very remote northeast section of Arizona near the village of Kayenta. Travel to this section of the country was not easy even at this late date, and it was an eight hour drive from Farmington, New Mexico to Kayenta, Arizona, a distance of some 130 miles. The trip was over roads that even' a-horse and wagon had trouble negotiating and a four wheel drive vehicle was about the only type of transportation that could satisfactorily traverse these roads, as testify many badly beaten sedans and coupes that tried it. Since that time a very excellent road has been constructed from Shiprock; New Mexico to Cameron, Arizona where it junctions with another excellent road that runs north to Page, Arizona and the Lake. Powell area and south to Flagstaff, Arizona on highway 66. Kayenta is a small village nestled at the foot of the Black Mesa near its northeast extremities. The coal deposits of interest were on the surface of the mesa. This location presented another problem, as the only trail to the top of the mesa was intended for walking, horseback, or a brave soul In a horse and wagon. Once again the four wheel drive vehicle was about the only answer. To reach the coal deposits you must climb the mesa, which is vertical ascent of some 1,500 feet, and then proceed southward into the bowl of the mesa with an ensuing descent of some 1,000 feet, finally coming to an elevation of 6,500 feet, at which elevation the coal outcrops become apparent.

Jan 1, 1969

By J. A. Dos Santos

"INTRODUCTION Dramatic reduction in energy use and environmental impact can be achieved with sandwich belt high angle conveyors that serve as the vital link in any IPCC (In-pit Crushing and Conveying) system. These high angle conveyors are not new at all, but have not found wide use in IPCC systems where they can realize the greatest advantage. Reduced energy consumption and environmental impact, with IPCC systems, was already realized in the 1970s. With the bulk material haulage limited to conventional open trough conveyors the most direct path out of the open pit was precluded, requiring low angle spiral ramps and/or deep slots and/or tunnels through the high wall of the open pit. These excavations, to accommodate the low angle limitations, represented undesirable impact on cost and on the environment. Against this backdrop, a major study in 1979 sought to develop high angle conveying systems that could continuously haul the mined bulk material directly out of the pit, along the high wall – the shortest distance between the two end points. Between 1979 and 1982, that study developed sandwich belt high angle conveying systems that utilized all conventional conveyor equipment including smooth surfaced rubber belts that could be continuously scraped clean. These systems had all of the positive features of conventional conveyors but overcame the angle limitation. By hugging the bulk material between two belts, the material’s internal friction could be developed to facilitate conveying at any high angle up to 90 degrees (vertical). After an intense testing period (about one year) on the first large scale prototype system, commercialization began in 1983 with the installation of a 60 degree incline system at a western United States coal mine, elevating 2000 t/h of coal to a train load out system. It did not take a long period of scrutiny and acceptance before this high angle conveyor found use in the most rugged requirements of an IPCC system. This was only the second commercial sale, and after more than 150 commercial installations, it remains arguably the most significant high angle conveying system. In 1984, a copper mine in Serbia, already using pit perimeter crushing and conveying, decided to move their primary crusher deep into the pit and to use a sandwich belt high angle conveying system to elevate the ore continuously, directly out of the pit, along the high wall to the pit perimeter where it then transferred to a conventional conveyor for the remaining haul to the plant. The system had significant features including 2000mm wide belts that elevated 250mm coarse ore, at 4000 t/h, over six 15-meter high benches for a total 90 meters of net lift. The system was able to reduce the truck haulage fleet by ten 200 ton trucks realizing great cost savings, zero emissions to the air and greatly reduced traffic congestion in the pit. The system operated successfully until 2002 when the mine shut down. Many successful sandwich belt high angle conveyors followed with the current count of commercial installations at more than 150. Despite the great success with this system, its use has not been repeated as part of an IPCC system."

Jan 1, 2018

By Cameron Dunn, Callum Fryer, Carmen Hu, Craig Sewell, Peter Stakne, Andrew Raine

The Woodsmith Project is located in north-eastern England within the North York Moors National Park. The strata contains the world’s largest known high-grade Polyhalite resource of around 2.66 billion tonnes. The Project was initiated by York Potash Limited (YPL), a subsidiary of Sirius Minerals plc., but in March 2020, a takeover was completed by Anglo American, one of the largest mining companies in the world. Polyhalite is an evaporite mineral and contains essential nutrients required for plant growth. The Polyhalite will be extracted via two deep mine shafts and transported underground from the mine site to a Materials Handling Facility on a Mineral Transport System (MTS), which comprises a high-capacity conveyor belt system located within a 4.9 m ID tunnel. In 2018, STRABAG were awarded with the design and construction of the MTS tunnel and associated infrastructure, including the high-capacity conveyor system. The scope of work consists of 300 m of open cut, 100 m SCL tunnel, 36.5 km TBM drive (originally anticipated as three separate TBM drives) along with a network of underground caverns at the Woodsmith Mine. The construction of two 380 m deep intermediate access shafts was later awarded as Amendments to the Contract. The tunnel is constructed using a Herrenknecht Single Shield TBM. As a result of how the various elements of the project have developed over time, the first TBM drive has been extended to ~29 km making it the worlds longest single heading TBM Tunnel when complete. The option of completing the entire tunnel length with a single heading TBM drive is currently being assessed by Anglo American and STRABAG. This unprecedented tunnel length requires two intermediate shafts to provide essential access and services, the first intermediate shaft is at Lockwood beck (LWB) and the second is at Ladycross (LDX). The LWB shaft has been constructed utilising the innovative Blind Boring technique never used before in the UK. This paper will explain the methodology and technical risk management associated with this technique. The authors believe that the collaborative approach between all contract partners is and continues to be the important contributor for the success of this project.

Jun 13, 2023

By Gavin Erickson, Lucas R. Moore, Clint Stoddard, Garret Bryant

As global mineral feed grades decline, phosphate beneficiation faces mounting challenges. Chief among these being achieving high recoveries of industry quality concentrates from ores of decreasing quality. Apatite, a critical mineral for meeting global fertilizer demand, remains the primary source of phosphorus and is typically recovered through beneficiation by multi-stage flotation. However, traditional saponified fatty acid collectors lack the selectivity needed to beneficiate these lower quality ores, which are containing a higher concentration of more complex gangue minerals. Enhancing collector performance is essential to the industry moving forward. This study introduces a novel alkyl polyglucoside based surfactant designed as an additive for conventional fatty acid systems. Its incorporation significantly improves the grade recovery in direct apatite flotation, even at low concentrations. Flotation results as well as surfactant properties will be discussed.

Feb 22, 2026

By E. Lee Bray

"Editor’s note: The editors thank those who make this annual issue possible. A special thank you goes out to the Industrial Minerals Annual Review editor, to the Industrial Minerals & Aggregates Division Technical Committee chair and vice chairs, and to the authors of the individual commodity profiles.Jim Norman, member SME, of Tetra Tech Geo, is the industrial minerals annual review editor. Edgar Blanco, member SME, of Freeport- McMoRan, is chair of the Industrial Minerals &Aggregates Division’s Technical Committee.The technical committee vice chairs include:• NickTushar Gupta and Sallie Gaillard, of the USGS, members SME, agricultural materials.• Abhishek Choudhuryand Xihui Yin, members SME, of Montana Tech and Kemira, repectively, ceramic and refractory materials.• Bobbi Strange and Riddhika Jain, members SME, of Outotec, Martin Marietta and Outotec, respectively, chemical raw materials.• Snehamoy Chatterjee, Alyssa Kendir and Alind Chandra, members SME, of BMT, Universityof Kentucky and Michigan Tech, respectively,construction aggregates.• Subham Verma, Gauran Soni and Freddy Sime, members SME, fillers and pigments.• Kaiwu Huang, Thomas Hilderbrand and Ricardo Santander members SME, of Virginia Tech, Thiele Kaolin and Carbo Ceramics, respectively, sorbents, filters and process aids.• Rhaghay Dubey and William Rapier, members SME, of Outotec and a consultant, respectively, specialty minerals.On behalf of ME readers, the editors thankTwo U.S. alumina refineries produced an estimated 1.5 Mt (1.65 million st) of alumina from imported bauxite in the United States in 2018. The 500-kt/a (550,000-stpy) refinery in Burnside, LA, owned by Almatis Inc. produced specialty alumina used in the abrasives, ceramics, chemical and refractory industries. The 1.2-Mt/a (1.32 million-stpy) refinery in Gramercy, LA, owned by Noranda Alumina LLC produced alumina mostly for use in aluminum smelters but also produced specialty alumina. An upgrade project at the Gramercy refinery to convert 200 kt/a (220,000 stpy) of capacity to produce more profitable specialty alumina was completed in the first half of 2018, and another project to increase capacity was started but a completion schedule was not available. The amount of new capacity was not disclosed, but it would be used to produce nonmetallurgical grade alumina. The 2.3-Mt/a (2.5 million-stpy) refinery in Point Comfort, TX, which was temporarily shut down in March 2016, remained closed throughout the year."

Jul 1, 2019

By G. T. Austin

Every year the United States consumes millions of dollars worth of abrasive materials as blasting media. Entrained in either a gas or liquid stream or propelled by paddles or wheels, they are directed onto the surface of another material to modify that surface. The modifications to impacted surfaces include cleaning, cutting, deburring, etching, finishing, and peening. Blasting media can be either organic or mineral abrasive materials. Information and data presented are for only a portion of the mineral abrasives, they are; fused aluminum oxide, coal slag, copper slag, garnet, metallic shot and grit, nickel slag, olivine, silica sand, silicon carbide, and staurolite.

Jan 1, 1994

By R. L. Godfrey

The Custom Coals advanced coal cleaning plant will be designed with a unique blending of existing and new processes to produce two types of compliance coals: Carefree Coal? and Self-Scrubbing Coal?. Carefree Coal will be produced by cleaning the coal in a proprietary dense media cyclone circuit utilizing fine magnetite to remove up to 90 percent of the pyritic sulfur and correspondingly greatly reduce the ash. While may utilities can achieve full S02 reduction compliance with Carefree Coal, others face higher sulfur reduction requirements due to the higher sulfur content of their existing fuel supplies. For these circumstances, a patented Self-Scrubbing Coal will be produced by taking Carefree Coal and pelletizing limestone-based additives with the finest fraction of the clean coal. These technologies will enable over 150 billion tons of non-compliance U.S. coal reserves to meet compliance requirements.

Jan 1, 1995

By Jack Bedder

"Editor’s note: We would like to thank those who make this annual issue possible. A special thank you goes out to the industrial minerals annual review editor, to the Industrial Minerals & Aggregates Division Technical Committee chair and vice chairs, and to the authors of the individual commodity profiles.Jim Norman, member SME, of Tetra Tech, is the industrial minerals annual review editor.Ebrahim K. Tarshizi, member SME, of Michigan Tech, is chair of the Industrial Minerals &Aggregates Division’s Technical Committee.The technical committee vice chairs include: • Hyunjung Kim, member SME, of Chonbuk National University, agricultural materials.• Xihui Yin, member SME, of Kemira, ceramics and refractory materials.• Nikhil Gupta, member SME, of Virginia Tech, chemical raw materials.• Jasson Giddens and Swadhin Saurabh, members SME, of Oil Dri Corp of America and Mill Creek Engineering, respectively, chemical raw materials.• Snehamoy Chatterjee, member SME, of the Michigan Tech.• LeDeana Roberts and Shubham Verma, members SME, of Imerys and U.S. Oil Sands, respectively, fillers and pigments.• Thomas Hilderbrand and Kaiwu Huang, members SME, of Thiele Kaolin Co. and Virginia Tech, respectively, sorbents, filters and process aids.• Rhaghav Dubey and Edgar Blanco, members SME, of Outotec and FL Smidth, respectively, specialty mineralsAntimony generally occurs along with gold, lead, copper and silver. There are more than 100 antimony minerals, although the sulfide mineral stibnite is the main one.Antimony enters the supply chain either as a result of mining (primary production) or recycling (secondary production). China has by far the largest antimony resources and is, as a result, the world’s center for antimony mine production. In 2016, it accounted for more than three quarters of the global mine supply out of a world production figure of 130 kt (143,000 st), according to the U.S. Geological Survey. The biggest, and most high-grade deposits are found in southern China, with the largest mines located in Hunan, Guangxi and Yunnan provinces. Tajikistan, Russia, Australia and Bolivia are the largest mine producers outside China. A new antimony project in Oman made progress in 2016, producing first metal in April 2016 in test facilities, and then ordered three furnaces for a 26 kt/a (28,600 stpy) antimony metal and oxide smelter that is due on stream in late 2017.Antimony ingot production is not as widespread as is antimony mine production, owing to the high levels of pollution that are associated with antimony smelting. It is for this reason that smelting has been largely confined to China and other Asian countries, where environmental legislation is less stringent.Antimony oxide production is undertaken on four continents with China being the biggest producer. There is also a considerable amount of oxide production in Europe — which relies on imported feedstock, mostly from China. Antimony also enters the supply chain through recycling. Lead containing antimony is produced in a number of countries, mainly in secondary lead smelters. Typically, a blast furnace charge containing used or discarded battery plates, type metal or bearing metal is reduced to lead bullion, which is refined in reverberatory furnaces and melting pots. In the main, the antimony recovered is consumed in metallurgical applications. China was the biggest secondary antimony producer in 2016, and accounted for 25 retardants and lead-acid batteries. Flame retardants accounted for roughly 50 percent of consumption in 2016 with batteries representing about 25 percent. Other end uses include plastics and heat stabilizers, ceramics and glass and a variety of metallurgical applications. Demand has been sluggish since the global financial crisis, mostly because key markets failed to recover strongly from the downturn, particularly in Europe."

Jan 7, 2017

By J. Fuchs

This paper describes the mechanized narrow vein cut-and-fill approach used for the Deep Copper orebody at Falconbridge Limited's Strathcona Mine. Strategies for achieving high productivity while maintaining ground stability at depth and controlling dilution are discussed, including the use of mini-electrohydraulic drilling equipment, containerized truck haulage, consolidated rockfill placement techniques, and a miners' incentive system.

Jan 1, 1992

By J. Noll, J. A. Organiscak, A. B. Cecala

"In recent years, significant strides have been made to optimize the design of filtration and pressurization systems used on enclosed cabs of mobile mining equipment to reduce respirable dust and other contaminants and provide the best air quality to the equipment operators. This synergetic effort has involved original equipment manufacturers building mining equipment, manufacturers of heating, ventilation, and air conditioning systems for mobile equipment, filtration and pressurization system manufacturing companies, as well as the National Institute for Occupational Safety and Health, and other government organizations. Considering all the advances made in this area over the last decade, one aspect that NIOSH still needs to assess is the longevity of optimal cab performance with respect to the quality (filtering efficiency) of the filters used in filtration and pressurization systems. In today’s culture, most health and safety professionals automatically believe that HEPA quality filters need to be used to provide the greatest level of protection to workers. Researchers at the Office of Mine Safety and Health Research for NIOSH hypothesized that HEPA quality filters may not be optimal for the mining industry and speculated that MERV 16 rated filters would be more appropriate in most cases. In order to test this hypothesis, NIOSH performed a two-year study comparing both HEPA and MERV 16 quality filters on two pieces of underground limestone mining equipment, being a roof-bolter and face drill machine. Testing showed at the 95 pct. confidence level that there was no statistical difference between the two efficiency filters on both pieces of mining equipment. Since the MERV 16 rated filters were less restrictive and provided greater cab pressure, and since they did not have to be replaced as often as the HEPA quality filters, researchers concluded the MERV 16 filters were the optimal choice for both pieces of mining equipment in this case study comparative analysis. INTRODUCTION When most health and safety professionals today think about filtration efficiencies and their correlation with protecting workers’ health, the normal assumption is the higher the efficiency of a filter, the greater the protection afforded to the workers. The next logical step is to believe that HEPA filters deliver the greatest protection for workers because they provide the highest filtering efficiency. Obviously high-efficiency intake filters are a necessity for an effective cab filtration and pressurization system on mobile mining equipment, but what is the optimal filter efficiency rating for achieving high levels of cab protection factor performance over the service life of filters? To address this question, the National Institute for Occupational Safety and Health (NIOSH) has performed an in-depth laboratory research study over the years simultaneously with numerous field studies to retrofit used enclosed cabs on mobile mining equipment with newer and more effective filtration and pressurization systems."

Jan 1, 2016

By Arnold Dix, Oliver Heger, Bernhard Kohl

In the USA, risk-based decision making has not been a common approach to tunnel safety in the past, but this is changing, as concepts such as “equivalency” in the NFPA 502 framework gain acceptance in the USA and elsewhere. In other regions, in particular in Europe, risk assessment techniques have been used for nearly two decades in many jurisdictions as an additional tool to complement the application of prescriptive guidelines and support decisions related to tunnel safety. After some initial difculties these methods are meanwhile a well-established element of tunnel safety management. There are several tools available which have been practically applied and further developed over years, such as the Austrian tunnel risk model TuRisMo, or the PIARC owned DG-QRAM model. Whereas TuRisMo is a holistic, system-based model, which is best suited to quantify and assess re risk and associated mitigation measures, DG-QRAM focusses on the risks related to the transport of hazardous materials. Depending on the objectives and the scope of the investigation and the regulatory environment tunnel risk assessment tools are in use for different purposes, mainly to demonstrate a sufcient level of safety and to decide on and select additional risk mitigation measures. The international eperience substantiates that the general approach is eible and that the methods and tools are mature and can be applied for different problems in different environments. First case studies like the risk study on conditions and permissibility of the transport of hazardous materials through the Eisenhower-Johnson-Memorial Tunnel in Colorado demonstrate the applicability of a risk-based concept for decision making in the US-American environment.

Jun 23, 2024