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By S. S. Xue

A study has been conducted to remove iron from sulfate solutions using Eichrom's Dipex® extractant, P,P?-di(2-ethylhexyl) methanediphosponic acid (H2DEH[MDP]). It is found that this extractant can effectively and selectively extract ferric ion from highly acidic solutions. Ninety-nine percent of the iron was extracted from a simulated feed solution in a single stage. The separation factor, Fe/Zn, was 10 6 Over 90% of the iron in a loaded organic can be recovered in an aqueous solution by reductive stripping. This paper presents the experimental results. A new process for iron removal using Dipex extractant is described and discussed.

Jan 1, 1999

By Chamila Jinendra Nanayakkara, Nimila Dushyantha, Amila Sandaruwan Ratnayake, Gayithri Niluka Kuruppu

Rare earth elements (REEs) are key ingredients in many advanced materials used in energy, military, transportation, and communication applications. However, the prevailing geopolitical dynamics and the rising demand for REEs have rendered the reliance on primary REE resources susceptible to future supply disruptions, posing a substantial risk to the availability of these elements for numerous applications. Therefore, it is imperative to undertake substantial initiatives in the extraction of REEs from secondary sources on a large scale to ensure the resilience of the supply chain. Permanent magnets, lighting phosphors, and nickel-metal hydride (NiMH) batteries are among the secondary sources with high potential for sustainable REE extraction. This review assesses the extraction potential of REEs from the aforementioned three secondary sources and their leaching kinetics and thermodynamics aspects. More importantly, state-of-the-art different existing kinetic models employed in rare earth (RE) leaching were well discussed for a better understanding of the REE leaching reactions. Furthermore, the optimized leaching parameters related to this kinetics were described, and various RE recovery methods were comprehensively summarized. These processes facilitate to managing one of the fastest-growing solid waste streams by minimizing environmental impacts and producing critical metals, including REEs via circular economy approaches. The recovery of REEs from secondary sources aligns with numerous United Nations Sustainable Development Goals (SDGs), particularly in the renewable energy sector for climate change mitigation. Consequently, this trash-to-treasure urban mining concept to transforming e-waste into a valuable resource for REE recovery emerges as a pivotal element within the REE industry.

Dec 28, 2023

By PEILIN LAN, LEONARD HILL, SIMON TIMBILLAH, BERNARD FOSU, CESAR SOSA-BLANCO

The use of sodium hydrosulfide (NaHS) in most of the operations in by-product molybdenum flotation comes with safety concerns and, in some instances, a high reagent cost. Engineered solutions at the various operations where NaHS is used have reduced the possibility ofH2S gas evolution immensely. However, the threat of exposure remains, and this, coupled with the high dosages of NaHS consumed, supports the continued search for alternative depressants. This paper focuses on efforts to study the applicability of disodium carboxymethyl trithiocarbonate (DCMT), an organic depressant, as an alternative to NaHS. Benchscale rougher flotation results for samples from the Sierrita Cu–Mo plant showed the best DCMTperformance at 8 kg/t of DCMT and pH=10.5 with 30 min of shear conditioning and 10 min of flotation conditioning time. The Aminpro plant model simulation confirmed that DCMT with 4–8 kg/t under certain shearing and conditioning times achieved superior or equivalent Mo–Cu separation efficiencies when compared to NaHS.

Apr 19, 2021

By N. Damiano, C. Zhou, R. Jacksha, J. Srednicki

Modern electronic devices and systems used to enhance miner safety and health are becoming commonplace in underground coal mines. The ability for these devices and systems to function properly in the presence of electromagnetic emissions from other electronic and electrical devices and systems is not entirely understood. To investigate potential electromagnetic compatibility issues of critical mine electronic devices and systems, researchers from the National Institute for Occupational Safety and Health (NIOSH) are conducting surveys of electromagnetic emissions in underground coal mines. This paper presents the measurement system, methods, and results of electric field electromagnetic emission surveys conducted in three underground coal mine environments in the frequency range of 10 kHz to 1000 MHz. The survey data show that in some environments electric field electromagnetic emissions in underground coal mines approached or slightly exceeded limits as defined by other industrial sectors.

Mar 2, 2022

By Alain S. Kivava, Olawale K. Aromolaran, Charles Nzolang, Anthony T. Bolarinwa, Georges M. Kasay

Rare earth elements (REEs) are crucial in high-tech and green technologies. The Democratic Republic of Congo (DRC), rich in mineral resources, shows potential for REE deposits in carbonatites, pegmatites, and placers. This paper reviews global REE resources, highlights potential REE targets in Africa, and emphasizes the need for further research and exploration in the DRC to unlock its REE potential.

Feb 4, 2022

By Richard Emberley, Timothy Shaw, José L. Torero, Jurij Karlovsek, Timothy Gibson

"Tunnel closures are highly undesirable and the lengthiest are generally attributed to structural failures (e.g. Mont Blanc). Although historical data shows structural failures are closely linked to fire, design parameters for tunnel safety are not well defined. Current research has focused on defining the fire heat release rate and temperature, but these parameters cannot be easily used to determined structural performance. The energy transferred to the structure, the heat flux, is required but current literature lacks these values. Full scale experiments were undertaken on passenger vehicles resulting in heat fluxes between 20-70kW/m2. Analysis shows a vehicle fire’s duration is closely linked to its mass. Further analysis shows small vehicle fires can be scaled as a function of the tunnel diameter and the characteristic height of the desired vehicle. The present work provides engineers an appropriate design methodology to undertake informed thermal-structural analysis to minimize the risk of tunnel structural failure.INTRODUCTION Quantifying the effects of a tunnel fire depends on many factors such as the type of occupants, their vehicles and spacing, ventilation conditions and the geometric shape of the tunnel (Ingason and Lonnermark 2011). For design engineers investigating the thermal-structural performance of a tunnel, these factors are typically converted into spatial and temporal temperature distributions (Usmani et al. 2001) using various design curves such as those of ISO834-1, Hydrocarbon, Rijkswaterstaat (RWS) or RABT-ZTV (Promat 2013). However, to define a temperature profile through a structural element these curves require a heat transfer model that incorporates an appropriate boundary condition. The appropriate boundary condition is the net heat flux which is the result of a complex energy balance. For use in heat transfer calculations the net heat flux must account for the tunnel geometry as well as thermal properties of a given structural element and all other surfaces and mediums affecting the transfer of heat (Torero 2014)."

Jan 1, 2016

By George C. Hawley

Historically, mica usage has been low because of limited availability; as a by-product of many small processors, who have lacked motivation for extensive R & D. The discovery of a 30 million ton deposit of 85-90% pure phlogopite, when existing markets are only 300,000 tonnes annually, forced the search for large volume new markets. Increasing costs of energy, petrochemicals, plastics and glass fibers, and environmental constraints on asbestos usage, have led to new opportunities for mica as a reinforcing filler. Extensive research and developments; in beneficiating, processing and treating mica, has been necessary to satisfy these new markets.

Jan 1, 1981

By Sunny Murmu, Gnananandh Budi

One of the most significant concerns in longwall ground control is the instability and failure mechanism of the coal wall. The current research uses FLAC3D to simulate panel 1 of the Adriyala Longwall Project, India, in order to evaluate the distribution of vertical stress and material failure mode, in and around the longwall face. Additionally, three distinct criteria are used to evaluate coal wall spalling: vertical stress distribution, maximum shear strain, and residual cohesion. A novel algorithm is also proposed to appropriately capture roof bed caving, shield installation and advancement, and coal extraction from the face. The findings of the modelling show that progressive longwall extraction creates an elliptical stress relief zone around the excavation void. During the peak stress phase, the height of the stress relief zone is greatest, whereas the width is highest during the main fall phase. As mining advances, the coal wall at the face line appears to lose its stress-bearing capability. Shear failure was the most common coal wall failure mode. Maximum spalling depth (MSD) and longwall face spalling index (LFSpI) were used to measure the extent and volume of coal wall spalling in FLAC3D. For panel 1 of the ALP mine, the MSD, and LFSpI were determined to be 3 m and 90.5 %, respectively. The mode of coal wall spalling was expected to be total or fragmented failure. The field observations and the numerical modelling findings were in good agreement. The compressive strength and deformation modulus of the immediate roof appear to have a substantial role in coal wall spalling. The results of the proposed numerical simulation exercise can help strata control engineers better detect the risks of coal wall spalling and enhance face control for safe and productive working environment at the longwall face.

Aug 8, 2023

By Mustafa Kumral, Samer Hmoud

Effective management of ore loss and dilution is essential for successful grade control and short-term mine planning due to their significant impact on the economic, environmental, and technical aspects of open-pit mining operations. Factors influencing ore loss and dilution fall into two categories: (i) controllable factors like mine equipment selectivity and blast design and (ii) uncontrollable factors such as spatial heterogeneity of ore and waste blocks on a bench. This paper focuses on the second category by applying spatial entropy concept to capture heterogeneity at the scale of selective mining units. In this paper, global spatial entropy is used to assess the impact of spatial heterogeneity between ore and waste blocks on the magnitude of ore loss and dilution, while the local spatial entropy can guide the allocation of blast movement monitoring balls pre-blast. High values of the global spatial entropy indicate increasing potential of ore loss and dilution, which reduce profit. Furthermore, the study investigates the relationship between spatial entropy, cut-off grades, blast movement, dig-limits optimization model running time, and profit through a number of case studies. The results show that changes in cut-off grade and blast movement can significantly affect spatial entropy post-blasting and increase ore loss, dilution, and profit reduction, revealing the need for controlled blasting at specific bench sections. Additionally, the results demonstrate an exponential increase in profit reduction due to ore loss and dilution with a rising global spatial entropy.

Nov 28, 2023

By C. Newman, N. Schaefer

"INTRODUCTION As underground mining continues to operate at deeper depths and in more complex geologic and geometric conditions, there has been an increased demand for higher design standards in ground control safety and stability within the mining industry. Over the past 20 years, NIOSH has developed, validated, and distributed a number of free software packages (ALPS, ARMPS, AMSS, ARBS, etc.) for the safe design of underground coal mines with respect to ground control. While these programs were initially developed on a, “stand alone model,” where all program data resides on an individual or workgroup computer, modern day web applications have begun to migrate toward a, “multiple-tier model,” allowing multiple users to access an application through an Internet connection. webGroundControl provides users with access to NIOSH ground control design software (ARBS, ALPS, and ARMPS) utilizing a web-based three-tier architecture allowing users to easily access ground control designs, perform on-demand calculations, and provide online collaboration between operational personnel and engineers through a web server. Given advancements in cloud computing as well as the expansion of Internet connectivity on the surface and underground, webGroundControl users will be able to access the applications anywhere (where permissible) at any time. As web-based computing technologies continue to advance and cloud computing gains popularity and momentum, there is an industry need to develop Internet based applications for mine and ground control design (Barczak et al., 2016). The purpose of this paper is to introduce and familiarize those in the mining industry with the basic framework and, more specifically, the user-interface of the webGroundControl application. It is expected that the mining industry will rapidly embrace this new product and webGroundControl will be a new paradigm for mining engineering computer applications. APPLICATION ARCHITECTURE With the advent of cloud computing, web-based applications have become more popular with their adoption of multiple-tier, or n-tier, architecture containing independently operating tiers. The three-tier application architecture utilized in webGroundControl (as outlined in Agioutantis and Newman, 2016) contains a Presentation Tier (Web Server), Logic Tier (Logic/Application Server), and Data Tier (Data Server) as shown in Figure 1. While tiers have the ability to be deployed across and operating on multiple servers, webGroundControl is currently being deployed on a single server located on a university desktop computer. The separation of the application into a series of tiers greatly increases the maintainability and scalability allowing for the adoption of new technologies that can be applied to a single tier without redesigning the software package. The Presentation Tier maintains the user interface translating client requests (through a web server) and displaying results (through a web browser). The Presentation Tier allows for on-demand access from multiple users and compatibility with a variety of personal computers, Smartphones, tablets, etc. on different operating systems. The Presentation Tier has been developed with respect to the HTML and JavaScript languages. Through the utilization of CSS, a coding language which describes the style of an HTML document, the webGroundControl display is able to spontaneously adapt to any browser and any screen. The development of the Presentation Tier will be discussed in more detail in subsequent sections of this paper."

Jan 1, 2017

By J. S. Lee

Alkyl hydroxamates are well known collectors for oxide copper minerals as evidenced by the large amount of published literature. Our studies on a wide variety of copper ores from around the world have shown that alkyl hydroxamates will recover most of the "floatable" oxide copper minerals from an ore. They are available commercially, and they offer many advantages over alternative technologies for oxide copper recovery. In spite of this, the full potential of hydroxamates has not been exploited in the industry. The objective of this paper is to provide relevant practical aspects and guidelines to facilitate successful application of hydroxamates in operating plants. A critical analysis of the available information and data, based on several case studies, notation testing, and microscopic analysis indicates that alkyl hydroxamates can effectively recover well-defined oxide minerals of copper, but not copper occurrences such as Cu-bearing goethite (often misidentified as cuprite) which report as Acid Soluble copper in chemical assays. Prior to any notation testing with hydroxamates, it is necessary to assess the various modes of occurrence of Acid Soluble copper using microscopic and microprobe analysis.

Jan 1, 1998

By A. A. Campoli

A stress control design strategy was developed to minimize the explosive failure of highly stressed pillars, during room-and-pillar retreat mining conducted between stiff immediate roof-and-floor strata. A confined core coal pillar strength model was based on in-mine geotechnical evaluations of successful room-and-pillar and longwall bump control designs. Tributary area and linear shear angle approaches were used to estimate development and gob side abutment pillar loads for supercritical section widths. Subcritical width sections separated by barrier pillars to control stress within total extraction panels were optimized with the boundary element program MULSIM/NL.

Jan 1, 1994

By F. Woller

The territory of Czechoslovakia is well endowed in deposits of a variety of industrial minerals. At present, 29 different types of industrial minerals are mined from some 600 individual deposits in Bohemia and Moravia only. About half of those production centres involves structural materials like aggregate and common brick clays and loams. A significant proportion of industrial minerals produced in Czechoslovakia are exported. Destinations of main products are shown in Figure 1. Production of industrial minerals in Czechoslovakia has a long history. Glass has been produced since the 14th century, sulphuric acid since 1578, graphite since 1750, and chinaware since 1790, to name just a few; but most of the present production comes from deposits developed during the past forty years. For a variety of reasons, only about 30 per cent of registered and explored industrial minerals deposits in the country are in production (Table 1). Two of the reasons may be the complexity of processing or conflicting interests of parties involved, but lack of market research, investment funds, or processing capacity have also had an impact on the level of utilization of the resource base.

Jan 1, 1992

By Yu-ren Jiang

Novel compounds of hydroxycarbamoyl carboxylic acids, including 2-hydroxycarbamoyl -3-methlcyclohexane carboxylic acid (HCMC), 2-hydroxycarbamoylmethyl decylen-4-yl carboxylic acid (HCDC) and 2-hydroxycar-bamoylmethyl tridecylen-4-yl carboxylic acid (HCTC) were synthesized. The flotation behaviors of diaspore, kaolinite and illite using these compounds as collectors were investigated. The flotation results revealed that the floatability of the minerals was, in descending order, diaspore and kaolinite, followed by illite, and the ability to collect the minerals was, in ascending order, HCMC and HCDC, followed by HCTC. At a dosage of 2×10-4 mol/L, both HCDC and HCTC show a strong ability to collect diaspore and a weak ability to float kaolinite and illite. The flotation recovery of diaspore is over 90% and that of kaolinite and illite less than 30%. Moreover, Fourier transform infrared spectroscopy (FTIR) spectrum and zeta potential, as well as the adsorption amount, indicated that the adsorption interaction between HCTC and diaspore was primarily a kind of chemisorption in the form of chelate rings, while the interaction between the collector and aluminosilicate mineral was dominated by physisorption. It was concluded that the novel hydroxycarbamoyl carboxylic acid compounds are highly selective collectors for the flotation of diaspore vs. aluminosilicate minerals.

Jan 1, 2011

By C. G. Anderson

The treatment of materials for the recovery of the precious metals imposes many processing and environmental challenges. Sunshine Mining and Refining Company has developed hydrometallurgical technology for recovery of values from refractory precious metal materials. At Sunshine, the industrial focus of these processes has been for the direct recovery of silver without cyanidation. However, recent work has indicated that these technologies can provide a means for treating complex, refractory gold concentrates. This will be the focus of this paper. The practice of pretreating ores and concentrates to make them more amenable to cyanidation is becoming more common. Several pretreatment options for sulfide concentrates containing gold include roasting, bio-leaching, direct pressure oxidation and nitrogen species catalyzed pressure oxidation. The industrial use of nitrogen species catalyzed pressure oxidation has been limited to the Sunshine refinery where its focus has been for the treatment of silver concentrates. Much of the reluctance, outside of Sunshine, to use this type of technology may be based on the perception that high costs are associated with using nitrogen species (e.g. nitric acid, sodium nitrite) to leach. Also, the use of nitrogen species catalyzed pressure oxidation on an industrial scale is unfamiliar to most metallurgical professionals. A summary of pressure leaching processes which utilize nitrogen species as a catalyst is presented in Tables 1 and 2.

Jan 1, 1996

By I. Chatterjee

The application of microwaves has a demonstrated potential for the ultimate removal of water from fine coal. The principle of microwave drying of fine coal is based on the selective absorption of microwaves by water. Coal is a poor absorber of microwaves. As a result, water can be removed from fine coal by selectively heating water molecules. One of the difficult problems drilling microwave heating is the exact determination of temperature in the core of the materials. The electromagnetic energy absorption in coal/water mixtures during microwave drying is controlled by several factors including the dielectric properties of the constituents. In this paper the dielectric properties of various ranks of coal are presented as a function of frequency and moisture content. The measured dielectric data are incorporated into electromagnetic and thermal models of coal which predict the energy absorption and temperature distribution during microwave heating.

Jan 1, 1990

By H. E. Rojas

The primary objective of most comminution operations is liberation; however, mill performance is generally quantified in terms of particle size. Only recently has the use of image analysis equipment made it possible to quantify mill performance on the basis of liberation. In this investigation, a series of tests were carried out to study the effect of mill operating parameters on the liberation of sphalerite from a sphalerite/dolomite ore. The parameters studied included mill rotational speed, mill loading and ball size. The results of this work appear to indicate that sphalerite liberation is improved under conditions that promote impact breakage, while dolomite breakage is enhanced under attrition conditions.

Jan 1, 1990

By L. H. E. Weyher

Minerals beneficiation commonly requires initial crushing and grinding so that the mineral phase we seek to concentrate is adequately liberated to obtain a product of specified grade at optimum recovery. To some degree this also is true for coal preparation. In the comminution process we liberate not only the product but also the tailings phase. The true objective is, therefor, to eliminate from the comminution circuit whatever particulate matter has reached specified liberation, regardless of whether the particle is product or tailings material. Overgrinding either of the two phases ties up mill capacity and usually also burdens the downstream processing steps by increasing costs or decreasing recovery, or both. In view of this situation, one would expect concentration steps to be commonly incorporated into the cominution circuit. The reasons this is not done may vary, but probably include the desire to utilize large scale unit operations, e.g., large mills, in conjunction with very simple processes. Hydrocyclones have satisfied this desire but may not always be employed for the right reasons. Hydrocyclones are indeed simple. They also are rugged and forgiving. Unfortunately, these virtues are frequently misused. The direct results are inefficient classification and overgrinding. The indirect results are added costs through recovery losses, unnecessary recirculation, and so on,

Jan 1, 1985

By Sandeep Kumar Jeripotula, Govinda Raj Mandela, Aruna Manglapady

The main aim of this work is to evaluate whole-body vibration (WBV) of dozer operators based on three sitting postures (i.e., with 15° lean forward inclination posture, vertically erect posture with no inclination, and with 15° lean backward inclination posture) in Indian surface coal mines. A seat pad tri-axial accelerometer was used to collect WBV data from six dozer operators for three different sitting postures. Results showed that except for Dozer-1, 2, 4, and 5 operators during lean forward sitting posture and Dozer-4 operator during vertical erected posture, no other dozer operators have exceeded an exposure limit value (ELV) of 1.15 m/s2 in any of the considered sitting postures. Similarly, the vibration dose value (VDV) based on exposure action value (EAV) of 9.1 m/s1.75 has surpassed for all the dozers. But no dozer operator has exceeded an exposure limit value of 21 m/s1.75. The outcome of the study infers that based on “above health guidance caution zone (HGCZ)” for daily vibration exposure, i.e., A(8) measurements, for the operator sitting in lean backward postures the vibration amplification was reduced by 32.89% less compared with lean forward posture and 16.23% less when compared with vertically erected posture. Similarly, based on VDV(8), the exposure to vibration for the lean backward posture was reduced by 33.34% when compared with lean forward posture and 17.11% less when compared with vertically erected posture. Based on the above observation, it is concluded that lean back inclination with a trunk flexion of 15° is a favorable sitting posture, as it exposes the dozer operators to minimum vibration.

By Taekhee Lee, Steven Mischler, Shawn Vanderslice

Diesel-powered equipment is widely used in the underground mining industry and their popularity results from properties including efficiency, versatility, reliability, and durability. In the U.S. approximately 7,700 diesel engines were used in 177 underground metal and nonmetal mines as of 2005 [MSHA 2005], and these numbers have likely increased since that time. Diesel engines have been shown to be a major contributor to submicron carbonaceous, respirable, and total particulate mass in the air of underground metal mines [Zielinska et al. 2002, McDonald et al. 2003], and their extensive use results in approximately 13,000 underground metal/nonmetal (M/NM) miners (MSHA 2005) in the U.S. being potentially exposed to aerosols and gases emitted by diesel engines (MSHA 2001, MSHA 2006). Exposure to diesel exhaust has been linked to adverse health outcomes including cancer, cardiovascular, and respiratory diseases (Attfield et al. 2012, Silverman et al. 2012), and in 2012 diesel exhaust was categorized by the International Agency for Research on Cancer (IARC) as a Group 1 human carcinogen (IARC 2012). Exposure to diesel particulate matter (DPM) is especially concerning for underground miners since underground mine environments have been shown to have some of the highest levels of diesel exhaust in the U.S. (EPA 2002, MSHA 2001, MSHA 2006, Pronk et al. 2009). Due to the potential for elevated DPM concentrations in mines, the Mine Safety and Health Administration (MSHA) promulgated a rule to limit exposures of metal/ nonmetal underground miners to DPM to an eight-hour time-weighted average (TWA) of 160 μg/m3 total carbon (TC) (MSHA 2001, MSHA 2006, MSHA 2008). Since this rule went into effect, DPM exposures have been reduced, but are still elevated when compared to other occupations (Pronk et al. 2009, Noll et al. 2015). MSHA compliance data between 2005 to the present show that underground blasters represent 21% of all DPM overexposures in M/NM mines and are one of the highest exposed professions in mining often resulting from low ventilation in the area where blasters are working. Because mines have difficulty controlling DPM in these low ventilation areas, additional control technologies may be needed to reduce exposures. Administrative controls, where miners work on off schedules or upstream of diesel vehicles to avoid the exposures to DPM (Noll et al. 2015) is one possibility, but these types of solutions are not always feasible or practical. A canopy air curtain is another potential control technology to help reduce exposures of blasters to DPM. Listak and Beck (2012) showed that this control technology reduced respirable dust concentration under a roof bolter’s canopy by 67%–75% and recommended air velocities greater than 0.5 m/s for dust reductions of greater than 50%. Additional work showed that a canopy air curtain could be designed for a shuttle car, and some initial testing by the National Institute for Occupational Safety and Health (NIOSH) showed reductions of respirable mine dust between 66% to 70%. As seen in Figure 1, the canopy air curtain delivers clean air over the operator’s breathing zone. A fan draws in air through a filter to capture the dust and then supplies clean air beneath the canopy where a miner is working. The use of the canopy air curtain to reduce exposures to diesel particulate matter was first discussed by Noll et al. (2020). In this study the diesel canopy air curtain (DCAC) reduced the DPM concentrations under the canopy by up to 90%. For this research the DCAC was designed to attach to the basket cover of an ammonium nitrate fuel oil ( ANFO) loader (Figure 2) and provide clean air blowing over the miners as they work in the basket. The initial tests used clean air drawn from the mine’s intake and did not try to filter the DPM from the air. Filtering DPM has extra challenges when compared to filtering mine dust particles. The particles of DPM are smaller (submicron and nanometer) than dust particles (greater than 1 micron); therefore, the filtration system must be adjusted to capture submicron particles. A MERV 13 filter was used in previous canopy air curtain research on mine dust control, but this filter is only designed to capture 50%–75% of submicron particles, and this capture efficiency is too low for removing DPM, so a higher efficiency filter is needed. Higher efficiency filters increase the pressure across the filter media which results in decreased airflow or leaks around the filter and reduces the effectiveness of the control for protecting miners from DPM. The optimal filter needs to capture DPM particles at a high efficiency while still allowing the needed airflows to prevent contaminated air from entering the miner’s breathing zone. Listak and Beck (2012) recommended velocities greater than 0.5 m/s for dust reductions of greater than 50%. However, airflows too high have been shown to reduce miners’ thermal comfort; Roghanchi et al. (2016) suggest the optimal velocity for thermal comfort is between 1–2 m/s. Thus, airflow over the miner should be limited to the range of 0.5 to 2.0 m/s. This current study presents the results from research evaluating the reduction of DPM concentrations, under the DCAC, when using a higher efficiency filter (MERV 16) to remove DPM from the DCAC airstream.

Feb 1, 2024