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By Artur Skoczylas, Paweł Stefaniak, Sergii Anufriiev, Wioletta Koperska, Maria Stachowiak

In many underground mines the excavated ore is produced during the blasting process. Drilling machines that are used to drill the blastholes, where later the explosives will be mounted, are crucial for this task. In order to optimize the currently used techniques, great emphasis is placed on increasing the efficiency and safety of blasthole drilling operations. The natural consequence is the development of monitoring systems and algorithms for processing operational and historical data. In this article, we present the result of the analysis of drilling data carried out as part of the IlluMINEation project. The paper proposes an algorithm for work cycle detection for drilling machines, together with the estimation of general operating parameters and diagnosing the drilling process on the basis of long-term data. Based on the available data, selected components of the drilling cycles have been indicated. Several approaches based on the parameters of the defined cycles are proposed. These approaches can be used in the future to create a full-fledged system for examining the effectiveness and safety of mining drilling rigs.

Jun 25, 2023

By C. R. DeGennaro, M. R. Girman, J. Bickson, J. P. Homer, C. C. Jobes

Between 2005 and 2021, a NIOSH internal review showed that haul trucks were involved in 54 incidents at surface mines in the United States. Haul truck collision warning and avoidance systems (CXS) can assist in preventing accidents at surface mines. CXS use technologies to detect people or objects and alarm to alert haul truck operators. Robust testing can help ensure that they detect objects without excessive false positive alarms. Testing and validation would increase confidence in and encourage implementation of a CXS. Researchers from the National Institute for Occupational Safety and Health (NIOSH) reviewed documents related to the evaluation and validation of CXS with two objectives: (1) to identify methods and parameters used to evaluate detection performance and (2) to identify gaps in CXS test methods and in detection performance. Stakeholders can use the findings from this research to guide implementation of CXS to improve safety at surface mines.

Mar 2, 2022

By Michael Murphy, Mark Van Dyke, VASU GANGRADE, Brent Slaker

Room-and-pillar mining in multi-level underground stone mines come with unique pillar stability issues. The pillar stability in these mines primarily depends on the thickness of interburden between mining levels and the staggering of pillars. NIOSH has previously established pillar design guidelines for shallow, flat-lying mines and single-level operations, but there is little guidance for ground control design in multiple-level stone mines. Therefore, to improve the overall understanding of ground control in these mines, a microseismic monitoring system has been installed at a multi-level underground stone mine in Tennessee with up to a 243-m overburden and a 7-m interburden thickness between levels. The microseismic system is comprised of nine uniaxial accelerometers and one triaxial accelerometer installed in the interburden. The seismic array is locally focused with all sensors installed within a 625 m2 area and is setup to monitor the seismicity around the formation of the pillar in the lower mining level. Data is collected over 11 months and comprises of over 1,000 high-confidence events that have been located in the study area comprised of post-blast activity. The event locations were identified using a 3D-velocity model, with an average 4-m location accuracy for this array calculated using the system data. Most observed seismicity was on the excavation boundary, both in the interburden and in the roof of the top level. At this stage of analysis, there are no significant rock failures with which to correlate seismicity, but event locations correlate well with presumed damage in the vicinity of blasts.

Apr 26, 2022

By J. L. Mehaffey

A variety of chemicals offered by Armak were evaluated as dewatering aids for aqueous slurries of silica sand, sparsand and feldspar; an established commercial dewatering aid was used as a control. A number of Armak's potential dewatering aids yielded lower moisture retention values than did the commercial product on all of the mineral samples. In addition to the chemical dewatering evaluations, some of the mechanisms involved in the removal of water from these mineral samples were examined.

Jan 1, 1983

By J. Baz-Dresch

A custom-designed shotcrete system, consisting of an 8-m3 (10-cu-yd) transit mixer and a shotcrete spray boon carrier, is used by a two-man crew to transport and place up to 25 m3 (32 cu-yd) of steel fiber reinforced, dry, silica fume shotcrete per 11-hour shift. Shotcrete is custom blended by a local supplier and delivered predampened. Mix design and quality control are performed with a computer program that develops and graphs a properly balanced mix based upon the materials sieve analyses.

Jan 1, 1992

By Y. H. C. Wang

A detailed study of carrier flotation of kaolin clay using calcite showed the major beneficiation mechanism to be enhanced aggregation between anatase and calcite under intense agitation conditions. In order to develop an understanding of this selective aggregation, surface charge characteristics of kaolinite, anatase and calcite were studied under simulated flotation conditions. Zeta potential of all these minerals tended towards a constant negative value in ole- ate solutions under certain conditions possibly due to adsorption or precipitation of oleate on them. However, whereas the zeta potential of anatase in the oleate solutions was not influenced by the agitation level, that of kaolinite was found to be strongly dependent on the agitation intensity. The effect of oleate on zeta potential of kaolinite was reduced by an increase in agitation intensity. It is suggested that oleate is much more firmly bound to the surface of the anatase and that this preferential attachment is responsible for the enhanced selective aggregation of the anatase with calcite. Agitation level plays a major role in carrier flotation since intense agitation is considered to en- hance both the chemisorption of oleate on anatase and preferential detachment of calcium oleate precipitate from the kaolinite surface, all of this producing a large difference in the surface properties of anatase and kaolinite, and hence in their tendency to aggregate with calcite.

Jan 1, 1981

By E. M. Frizzell

It is unlikely that improvement in truck efficiency and capacity can fully offset the effects of inflation, fuel cost/shortages, and increasing haul distances as in the past. Therefore, investigations of haulage systems less sensitive to these problems are warranted. Thus, this Bureau of Mines contract research study on alternative continuous haulage systems was prepared. This study identifies the physical, economic, and technological parameters in the application of continuous haulage systems with special attention to under pit slope conveyors and skip hoisting systems. The evaluation data were gathered from extensive literature searches, European/North American mine visits, and industry comments. The study concludes that continuous underground haulage is a viable method within the proper geometric configurations.

Jan 1, 1979

By William J. Miles

For compliance with the Hazard Communication Standard and other federal and state regulations, numerous minerals, chemicals and products need to be evaluated for crystalline silica content at a threshold of 0.1 %. The polymorphs of crystalline silica that can occur in chemical and mineral products are quartz, cristobalite and tridymite. Other natural, industrial and synthetic amorphous silicas and hydrates must be distinguished from these polymorphs to prevent over-regulation in the workplace and environment. A number of industrial silica products are composed of glasses, expanded perlite, diatomite, slags, and precipitated and fumed silica products. Amorphous silica hydrates used for industrial products, include opal (hydrated silica of biogenic or inorganic origin), perlite, pumice and tuffs. In addition, crystalline and amorphous silicate minerals and chemicals, abundant in nature and industrial products, must be distinguished from the polymorphs of crystalline silica.

Jan 1, 1997

By S. K. Kawatra

Outokumpu Electronics has designed a new on-line coal slurry ash analyzer, based on an instrument developed at Michigan Technological University. The primary goal was to build an accurate instrument at the lowest possible cost. The instrument determines ash content from measurements of x-ray backscatter, iron Ka fluorescence, and low-energy y-ray absorption. It is capable of measuring the ash content with a standard error of 1.1% ash over an analysis range of 9-21% ash and 7-22% solids. The analyzer was tested on coals from United States, Poland, Great Britain and the USSR.

Jan 1, 1992

By George H. Davis

Much concern has been expressed recently as to whether water supplies will be sufficient to support accelerated energy development foreseen in operation Independence. Taking the Nation as a whole, sufficient water is available for energy growth, but locally, as in arid parts of the Colorado Basin, limited water supplies will dictate economies in water use and affect plant siting. As Young and Thompson1 point out with respect to electric power generation, the term "water requirements" is misleading, as demand for water for cooling is sensitive to price of water and thus is quite flexible rather than the inflexible or fixed level implied by the word "requirement." Much the same is true of other energy conversion systems. Water is used in many aspects of energy production including mining and reclamation of mined lands, on-site processing, transportation, refining, and conversion to other forms of energy. In the East, South, Midwest, and along the seacoasts, water supplies are generally adequate for energy industries; most water problems in those regions relate to pollution rather than supply. West of about the 100th meridian, however, runoff is generally less than potential diversions and energy industries must compete with alternative uses for the limited available water supplies. Water is especially short in areas of less than 10 inches mean annual rainfall where natural precipitation generally is insufficient for establishing vegetation without irrigation. Extraction. The principal categories of extraction comprise coal mining, oil and gas production, uranium mining, and oil shale mining.

Jan 1, 1974

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 W. Miles

Introduction From a historical perspective, bentonite is the common rock term for various uses and applications. Its name originates from water-based muds near Fort Benton used for lubrication of wagon wheels during the 19th century migration to western territories (which are presently part of the United States) when the pioneers ran out of axle grease. From a clay mineralogy perspective, bentonite is composed primarily of montmorillonite, an expandable magnesium aluminum silicate clay mineral. When magnesium occupies an octahedral structural site that usually contains an aluminum atom, a negative charge is created. In order to neutralize negative charges, cations are drawn to the interlayer surfaces between clay mineral sheet structures. Modern applications for bentonite depend on the sodium or calcium cation populations and other characteristics of the clay mineral. When sodium is the dominant cation, the material is also called sodium bentonite, also known as swelling bentonite, western bentonite or Wyoming bentonite. When calcium or magnesium is the dominant cation, the material is called calcium bentonite, also known as nonswelling bentonite or southern bentonite. Swelling bentonite is recognized for its rapid hydration of interlayer sodium and subsequent dramatic expansion up to more than 20 times its original volume. Low shear can then disperse the hydrated sodium bentonite to form suspensions that increase viscosity and suspend solids. However, when shear is subsequently eliminated a sodium bentonite slurry gels. Characteristically, nonswelling calcium bentonite has relatively poor hydration properties and thus low expansion of the clay mineral. When subjected to low shear, calcium bentonite exhibits very little viscosity and poor suspension. Additionally, when shear is subsequently eliminated no more than minimal gelling takes place. The domestic and export markets related to both swelling and nonswelling bentonite are discussed below.

Jan 1, 2007

By W. K. Collins, C. L. Dahlin, D. C. Dahlin, W. K. O’Connor, G. E. Rush

Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results have been achieved using heat pretreated serpentine feed material and high partial pressure of CO2 (PCO2). Specific conditions include: 155°C; P002=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy has been utilized to investigate the appropriate feed characteristics, identify the process products, and interpret the mineral dissolution and carbonate precipitation reaction paths.

Jan 1, 2001

By Peter I. Brooker

The turning bands method for the simulation of spatially correlated data in two or three dimensions requires that the relation- ship between the covariance obeyed by the realizations first generated on lines, and the covariance of the two or three dimensional process must be solved. In three dimensions the solution is immediate, but in two dimensions the integral equation relating the covariances of the one and two dimensional processes is more complex. This is solved in this paper and is applied to the most common model used in ore deposit description, the spherical covariance.

Jan 1, 1984

By William T. Ingram

Early in the 60's the author served as Chairman of the Engineering Foundation's Coordinating Committee on Air Pollution Research. One of our objectives was the development of a study on the measurement of stack emissions. Three publications of the Foundation resulted from these efforts to focus attention on the stack sampling problem.1,2,3 Two of these were annotated bibliographies covering 197 references. The third reported the results of a workshop meeting at which some 21 individuals from research institutes, industry and government discussed the possible and probable areas of research that would add to or increase the ease, precision and utility of sampling gaseous and particulate matter emitted from stacks. The American Society of Mechanical Engineers has had in its Power Test Codes a Standard Code for Determining the Dust Concentration in a Gas stream4 since 1941, The American Industrial Hygiene Association has published, in its Air Pollution Manual,5 a Section on Stack Sampling. Industry and regulatory agency requirements for stack sampling have utilized some modification of the alternatives in methodology. There has been ho single guide to stack sampling that met the needs of those who have the need to know.

Jan 1, 1970

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 Wayne D. Gould

The Cities Service Company's Pinto Valley mine and concentrator lie about 6 miles west of the town of Miami, Arizona at an elevation of approximately 4,000 feet above sea level. The concentrator started its first ballmill in July 74 and all six were available by November. Every effort was made to reduce capital costs, consequently, each unit process was studied critically to eliminate excess capital costs without loss of efficiency. Equipment selection was made on the basis of proven dependability and operating costs rather than on low bids. The result is a very workable plant with some important innovations. The concentrator is nominally 40,000 tons per day. The flowsheet is typical with 3 stage crushing, single stage closed circuit grinding, flotation, regrinding of rougher concentrate and cleaning of the rougher concentrate. The major equipment list is: 1 60 x 89 Traylor Primary Crusher 1 84" x 20' Stevens-Adamson Apron Feeder 3 7' x 16' Double Deck Tyler Screen 3 7' Nordberg Standard Crushers 6 8' x 20' Tyler Screens

Jan 1, 1975

By R. S. Datta

Regulations on sulfur emissions have caused the electric utilities to evaluate various methods of meeting them. Low-sulfur, low-volatile coals can be burned alone or blended with high-volatile? coals. This option may be a cost-effective alternative to the installation of scrubbers on coal-fired combustion systems. In some blending applications, problems may be encountered because the low sulfur content and high calorific value of the low-volatile or other clean coal allow it to economically upgrade extremely poor quality coal. While this is done to meet specification purposes, actual boiler performance may be dominated by the poorer quality coal. Thus, the reputation of the low-volatile or other clean coal suffers. As a result of laboratory and full scale testing, conducted over the last five years, a model has been developed to evaluate the relative combustion characteristics of various coals and coal blends. A database for different coals has been gathered. This paper presents the model and shows how power plants and coal mine personnel can use it to evaluate their coals from different sources. It can be used to blend two or more coals from different sources so that thee blended coal has flame stability characteristics which are similar to those of the baseline coal.

Jan 1, 1991

By T. J. DeMull

The business of heap leaching requires accurate forecasting of metal production from the heaps. Business forecasts typically follow a format that project periodic (monthly, quarterly, or annual) product shipments based on anticipated operating results, e. g., tons of ore placed, grade of ore, and rate of leach extraction. Since revenue and cash flow are dependent on the metal production stream, forecasts of metal production are very important for project evaluation and business planning purposes. Nevertheless, production forecasts, particularly for new heap leach projects, have been prone to errors. The present paper identifies some of the pitfalls that would be encountered in preparing production forecasts for new heap leach operations and provides a checklist of considerations to assist in preparing a forecast. Also, the paper presents a case study of copper production forecasting used for the Sanchez Project, a heap leach operation located near Safford, Arizona, that is presently under development by AZCO Mining, Inc.

Jan 1, 1995

By J. L. Carr

On average, one to two fatalities occur every year when a miner is struck or pinned by a continuous mining machine (CMM). Proximity detection systems offer an effective means to prevent these types of injuries and fatalities by sensing the presence of a miner and automatically disabling machine motion. The Mine Safety and Health Administration (MSHA) is expected to finalize a regulation that would require the use of proximity detection systems on all CMMs. Approximately one-fourth of all CMMs in use in the United States are already equipped with such a system. The use of these systems will save lives, not only by automatically preventing accidents but also by acting as a tool for educating miners and reinforcing safe work practices. Researchers at the Office of Mine Safety and Health Research (OMSHR) have conducted a series of field evaluations to quantify the performance of these systems in an underground coal environment. These field evaluations measured the distance at which the warning and stop zones were activated. The technology provided consistent activation of the warning and stop zones under many of the conditions tested. However, some performance inconsistencies were observed which present opportunities to improve the reliability of proximity detection system technology. Some of the notable variables that caused significant changes in performance and should be considered in the design, implementation, and use of proximity detection systems include interaction with the trailing cable, performance changes during tramming, and orientation of the miner-worn component.

Feb 23, 2014