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By D. Collins, J. Winfield, V. Gangrade, B. Slaker, S. Braganza

"Researchers at the National Institute for Occupational Safety and Health (NIOSH) are investigating the unique pillar stability issues associated with room-and-pillar mining in dipping underground stone mines. The objective of this paper is to study the post-blast impact in and around a pillar, using microseismic monitoring. To accomplish this, a microseismic monitoring system has been installed at a dipping underground stone mine in central Pennsylvania. The microseismic system is comprised of 18 uniaxial accelerometers; 12 sensors are installed in a single pillar and 6 sensors are installed in the surrounding area. More than 4,400 microseismic events have been located near the study pillar following the blasts. The number of triggers increased significantly following the blast, and the trigger rate in the first five minutes was 60 triggers per minute and three triggers per minute over the next three hours. The processing of high-quality triggers indicated a large number of low magnitude microseismic events near the blasting face. The event locations were identified more accurately by using a 3D-velocity model, with an average 9 m expected location accuracy for this array calculated using the system data. Seismicity was absent from the core of the pillar, but significant numbers of events were found following cutter roof along a crosscut as it was developed as well as in the location of a rib failure event. Additionally, the events were located in the roof, showing high number of microseismic events within 0–10 m of the roof line compared to 10–30 m above the roof line.INTRODUCTIONGround control stability is essential to any mining operation for ensuring mineworker safety and health and preventing catastrophic failures of underground structures. The National Institute for Occupational Safety and Health (NIOSH) has conducted research in stone pillar design and has established fundamental pillar design guidelines for the underground stone industry, which resulted in the development of the S-Pillar program (Esterhuizen et al., 2011; Esterhuizen and Murphy, 2018). However, the data that makes up the S-Pillar database consists of shallow depth, flat-lying, single-level mining operations. Therefore, to expand this dataset and to develop guidelines for challenging conditions such as dipping and multi-level mines, NIOSH is currently conducting detailed pillar response investigations at mines with these characteristics. The study is being conducted using multiple research approaches, including seismic modeling and tomography, numerical modeling (Sears et al., 2019), stress monitoring, and LiDAR-based laser scanning (Slaker, Murphy, and Winfield, 2019). This paper discusses the findings from the microseismic monitoring system installed at the Pleasant Gap Mine, a steeply dipping underground limestone mine in central Pennsylvania."

Jan 1, 2019

By R. A. Wyman

What unusual features are there about finding, winning, and using the industrial minerals of Canada which may be of interest and yet not widely known. Have you, for example, ever wondered where the raw material for those distinctive greenish grey statuettes, so readily recognizable as Eskimo carvings, comes from? Although stone suitable for carving is obtained at several northern locations, in recent years the Federal government, the Quebec government, and one or two private companies have shipped supplies of various rock types from other sources to central distribution points in the Canadian north for the express purpose of providing Eskimo artists with raw materials for carving. Canada is well endowed with industrial minerals, the extent and variety of which may be observed by a perusal of Table 1. In this table, materials currently produced are shown in the left-hand column; materials which are bordering upon economic viability are listed in the middle column; and materials which have been found in Canada in possible exploitable quantity, but for which [ ]

Jan 1, 1970

By J. W. MacDonald

PROPERTY AND PRODUCTION: Around 100 Million Tons of Recoverable Coal are available from the approximate 10,000 acres allocated to the mine. Over 1300 acres of surface land holdings extend well beyond the limits required for plant site, storage tracks, water supply reservoir, settling ponds and waste disposal. COAL: Extensive core drilled testing confirmed the early indicated high quality of the #6 Seam Washability data show less than four percent of the' coal seam required removal to provide a superior product for the available market. PREPARATION PANT DESIGN: The limited needs enabled Preparation Plant Design to meet the requirements without inclusion of novel equipment. The simplified needs afforded ample opportunity for considering increased automation where advantage or economy was antioipated. Plant design included protection of opportunity for pre-drying in advance of air cleaning the fine coal and accommodations for addition of Dense Media separating equipment in event warranted or required by future market changes. Protection is also afforded for addition of Raw Coal Storage accommodations in event warranted. Figure I shows the Preparation Plant Flow Sheet.

Jan 1, 1961

By S. Rajan

Familiarity with NEMA standards and the influence of the power supply on the motor-load system permits the user to make the necessary decision as to whether a standard or special motor is needed for his particular application. This paper highlights the more important aspects of NEMA standards for ac induction motors from the application engineer's standpoint and the effect of the power supply on motor characteristics.

Jan 1, 1975

By Eugene M. Trisko

Presentation Overview State-Of-The-Art Scrub/Switch Analyses > Allegheny Power System > PSI Energy UMWA Phase I Coal Interests > 16 Phase I Scrub Plant Coal Profiles > Coal Price/Emission Allowance Interaction Southern Company Case Study > 2+ Million Ton Phase II Allowance Purchases > 10+ Million Ton Phase I Coal Switch > Georgia PSC Proposed Fuel Price Cap > Shift/Avoid Georgia Scub Costs Through System Allowance Purchases

Jan 1, 1993

By L. A. Roe

The year 1867 marks the first year of commercial production of phosphate rock in the United States. South Carolina produced almost all of the domestic output of mineral phosphate until phosphate mining began in Florida in 1888. During the period 1868 to 1949 the total marketed production of domestic phosphate rock was about 186 million long tons of which 71.5 percent was produced in Florida, 18 percent in Tennessee and 7 percent in South Carolina (1). From 1949 through 1960, Florida phosphate rock production has ranged Prom 71 to 77 percent of the total domestic production. Since three-fourths of the domestic phosphate production is from the Florida field, and since most of the phosphate from the Tennessee and Western fields is not processed, but used directly as electric furnace burden, this paper will concern itself almost entirely with water requirements for mining and processing ore from Florida. Figure 1 summarizes phosphate rock production for Florida vs. total United States production over the period 1947-1960.

Jan 1, 1962

By A. Noble

Linear circuit analysis (LCA) is a fundamental tool which has been used to evaluate mineral separation circuits during the preliminary design phase. Traditionally, the LCA methodology uses the analytic circuit solution to determine the relative slope of the circuit?s partition curve. This value is then used as an indicative performance measure suitable for the comparison and ranking of alternative circuit configurations. Unfortunately, the partition curve slope only reflects the separation potential of middling material. In most mineral systems, this material represents a small portion of the initial feed (due to liberation) as well as a small portion of the revenue potential (due to the incremental value). Respecting these limitations, the authors have developed new separation performance indicators which may be derived from the analytical circuit solution and used in LCA problems. These indicators inherently reflect the separation potential of pure material, providing a better indication of lost revenue due to misplaced material. The complete methodology has been integrated with prior software to produce the Heuristic Optimizer for Resource Separation Economics (HORSE).

Feb 23, 2014

By R. L. Grayson

Using powerful database management software, nested-field analysis and microanalysis of narratives have been made of West Virginia accident data, resulting in a new approach for targeting and prioritizing safety interventions by county, mine size, specific mine, job title, type injury, etc. and combinations of these parameters. The analyses have been useful in focusing training and discussion sessions on specific work problems, trends, conditions, and situations for targeted groups of miners. Application of the technique will be presented in this paper, along with comparisons of various mine performance measures.

Jan 1, 1997

By M. R. Carter

The Rochester Mining District is located some twenty-five miles NE of Lovelock, Nevada. The District was discovered and named in the 1860's by prospectors from Rochester, New York. For a number of years, they worked Rochester Canyon, sinking shafts and inclines and making open cuts. After reaching a depth of approximately eighty feet, the miners tapped an underground channel and were driven from these workings by a strong flow of water leaving pumps in the shaft and barely escaping with their lives. With the Rochester workings no longer accessible, the miners went to the southeast and established the Relief Mining District. About 1881, gold was found in the gravel at the mouth of American Canyon, to the east of Rochester. These placers were worked until 1895, first by the Americans who reportedly took out $1 000 000, and later by the Chinese who mined the gravel with great skill. It was estimated that the Chinese took out as much as $10 000 000.

Jan 1, 1987

By A. L. Holmes

This presentation in the open pit session deals with the development of a phosphate rock strip mine by CF Industries, Inc., a company that does not presently mine in the Central Florida Phosphate District. Land acquisition, engineering, financing and environmental permitting activities were begun in early 1975; site preparation, environmental monitoring and dragline construction began in mid-1975. The operation is due on-stream in late 1978. The reserve acquisition, permitting, and financing could each easily be developed into a separate paper of interest. Each, however, has been covered before for other mining ventures with similar capital and environment requirements. For that reason, I have chosen to discuss what CF Industries, Inc. is, why it is entering this new sec-tor of the agricultural chemicals business, and, to keep at least some technical basis, what design modifications are possible when the total mine output is used captively and it is unnecessary to have the flexibility to meet the numerous transportation and customer specification considerations. In an attempt to show the size and complexity of the CF organization, a brief description of existing facilities should help show why the big interest in mining phosphate rock.

Jan 1, 1977

By S. E. Valji

Clay slurries are normally dewatered using flocculents like sulfuric acid or aluminum sulfate. This type of flocculation is based on the electrolytic mechanism. For certain clay dewatering applications, this method of flocculation is unsatisfactory. Flocculation, based on the bridging mechanism, using organic polymers has been utilized to overcome such problem situations. This method of flocculation offers solutions not possible by previous methods. Normally these flocculents are used to assist dewatering. In this case, not only is dewatering promoted, but also further processing is assisted by a change in the dilatant character of the filter cake that is formed. Discharge of filter cake is easier, extrusion of filter cake on to conveyor dryer is possible or improved, and heat transfer and drying rates of the extruded filter cake are substantially higher. Both natural and synthetic organic polymers have been utilized for this purpose. Selection, application techniques, and economics are described.

Jan 1, 1965

By S. Bhamidipati

Abstract. Controlled flow is an aspect often desired in mine ventilation. This is normally obtained by using fans and regulators to achieve the required pressure balance in the system. Preference for a certain network layout of these control devices is influenced by technical as well as legal and economic factors. In this study, a model is developed based on an economic criterion by which an optimum layout of fans and regulators for a controlled flow system can be determined. The concept is analo¬gous to the critical path crashing. However, a linear programming package is used to demonstrate the solution procedure for a hypothetical venti¬lation network.

Jan 1, 1983

American Barrick Resources Corp. has come farther, faster in the last 11 years than any mining company in recent memory. Acquisition of Lac Minerals Ltd. in August 1994 now makes Barrick the largest gold producer in the world outside South Africa. In terms of market capitalization, the company is the world's most valued gold producer. American Barrick's 28.3-km2 (7000acre) Goldstrike property on Nevada's Carlin Trend, the primary engine for past growth, was purchased in 1987 for $62 million. Regarded as an attractive exploration target, Goldstrike instead propelled American Barrick to the front rank of world gold producers. In 1993, the company produced 50.75 t (1,631,988 oz), 44.78 t (1,439,929 oz) from Goldstrike. Reserves on the property totaled 905 t (29.1 million oz) at the end of 1993, the largest in North America.

Jan 1, 1994

By G. A. Shirey

Breakthroughs in software technology and in computer hardware capabilities have opened new opportunities to develop more accurate process simulators and to reduce the operating time to reasonable levels. As a result, there are several new simulation packages being commercialized for modeling coal preparation plants and pulverized coal-fired power plants, and the users of these packages are reporting significant improvements in process efficiency and operating costs by implementing the simulators' results. This paper provides an overview of some of the models currently in use at CQ Inc., including the ASPEN PLUS"" Coal Cleaning Simulator, the Ultramax® process optimization software package, and EPRI's Coal Quality Impact Model?. Case histories of specific applications are also presented.

Jan 1, 1995

By J. F. Burr, D. P. Snyder, G. W. Luxbacher

"The Mine Improvement and New Emergency Response Act (MINER Act) of 2006 established the Office of Mine Safety and Health (OMSH) within NIOSH and provided authority for awarding contracts related to the development and implementation of new mine technology and equipment. Subsequently, Congress provided additional funding to NIOSH to initiate and continue the program. OMSHR has fulfilled this Congressional mandate through annual Broad Agency Announcement (BAA) solicitations, directed Requests for Proposals (RFP) and Inter-Agency Agreements (IAA), and has further expanded the program through capacity building BAA contracts with U.S. university mining departments in the areas of mine ventilation and ground control. This paper describes the extramural funding program and broadly examines the results of the 150+ contracts issued to date, grouped into key focus areas. INTRODUCTION The Mine Improvement and New Emergency Response Act (MINER Act) of 20061 established the Office of Mine Safety and Health Research (functioning as the Office of Mine Safety and Health Research or OMSHR) within the National Institute for Occupational Safety and Health (NIOSH), and provided authority for awarding contracts related to the development and implementation of new mine technology and equipment. The OMSHR external contracts program was formed in accordance with the MINER Act and has since issued over 150 contracts focused on worker health and safety. Initial funding for this program was provided by Congress through two Emergency Supplemental Appropriations (ESA) and was focused on emergency oxygen supply, communications and tracking, and refuge chambers (also referred to as refuge alternatives). Since the MINER Act, Congress has continued to fund the program through the annual NIOSH mining appropriation. The program was supplemented starting in 2009 with an academic capacity building program directed toward developing university tenure-track faculty and facilities and supporting graduate students in the area of mine ventilation; ground control was added as an additional focus area in 2011. A short synopsis of each contract is published on the NIOSH Mining website2 and final reports are available in digital form on request. A summary of the progress OMSHR has made over the 10-year period since the Act was published previously.3"

Jan 1, 2018

By Wayne D. Gould

Planning for a project does not start with the announcement of the approval for a project. Planning actually begins when the project is only a prospect and it involves the years of experience of many people because their expertise influences the final decisions. In partial anticipation of the Pinto Valley project, as well as a search for improvement in the Copper Cities operation, two projects were undertaken. The first project was to substitute one 26" cyclone for three 20? cyclones in the single stage grinding circuit. The second project was to replace the Hunt air flotation cells with 300 cubic foot mechanical cells. The 300 cubic foot cells were just being introduced, consequently two types of cells were selected for testing. The results from both projects influenced the decisions on equipment for the Pinto Valley project.

Jan 1, 1975

By Don Runge, John T. Zeni

Cuprex Limited is currently developing a small gold mining operation in Central Australia in the Tennant Creek field. In February 1984, the company undertook a feasibility study on the project and operations commenced in August 1984. Ore reserves are located between 230 and 280 metres (755 ft and 919 ft) below surface and ore extraction required the establishment of a shaft network for access, ore hoisting and ventilation. Zeni Drilling Company from West Virginia, U.S.A. was contracted to blind drill two shafts for the project. Blind drilling was selected for various reasons, including timing which related to cost efficiency. The blind drill shaft technique has proved successful in this application and with enthusiastic and innovative support from the mining industry, will prove an efficient and cost effective means of accessing and operating underground mining projects of all sizes in the future.

Jan 1, 1987

By J. V. Belke

There are many aspects of a grinding mill supply and installation that can result in the mill not operating as intended, resulting in unplanned shutdowns, poor reliability and headaches for all concerned. One of the largest aspects, both in criticality and physical mass, is the mill foundation; if not properly specified, designed and constructed the mill operation will be compromised. The mill foundation starts with the design specification and loading diagram supplied by the mill builder. The importance of understanding these documents and how to apply them is critical for the start of any mill project. When designing mills with a GMD the foundation must be properly modeled to ensure that all interactions of the mill and motor structures, foundation and subsurface strata behave in the intended fashion. All of the previous efforts can be laid to waste if the construction of the mill foundation is poorly handled. Mill foundations are typically the most massive concrete structure at a processing plant and can easily cause nightmares for inexperienced contactors. This paper explores some of the more important facets along the lifecycle of the grinding mill foundation.

Feb 23, 2014

By Wayne L. Johnson

The depth capability of engineering seismographs has been greatly increased by the use of signal enhancement, a technique in which seismic waveforms created by repeated impacts are digitized, stored, and summed. Summation amplifies the signal and partially cancels background noise. This gives a clearer picture of the wave aid makes it possible to determine the travel tune of signals from 'eater depth. Signal enhancement combined with continuous display of waveform, permanent recording of waveform, and precision digital readout of travel time has opened new fields of application in mining and engineering. Recent work has clown that replacement sulfides can be distinguished seismically from country rock at Bistee, Ariz. Work on the Iron Range of Minnesota indication,: that, by using a 300 pound weight as the source, the Biwabik iron Formation can be traced down dip to several hundreds of feet traverses over known areas show that reflections can sometimes be identified. Reflection, if identified preclsely, give a mere accurate estimate of depth and buried topography. Comparison of ( ) and weight drop have given some understanding of low wave amplitude varies win; source candid

Jan 1, 1971

By S. K. Kawatra

It is common in coal-cleaning operations to produce a fine waste stream which contains a considerable amount of coal, but which is not economical to recover both because it is mixed with large amounts of difficult-to-remove clay slimes, and because the fines are often heavily oxidized. Conventional froth flotation machines cannot produce an acceptable product from such material in a single stage of flotation, and even flotation columns often have difficulty cleaning this type of feed. A new type of flotation column was designed specifically to deal with these problems, and was installed and tested in a coal-cleaning plant in Ohio. The feed coal contained 39.8% ash as fine clay, and 2.83% total sulfur, and was 80% passing 176 micrometers. The coal was a thickener product which had oxidized for some time, and was very difficult to float. However, using the new column it was possible to recover up to 85% of the calorific value in a product containing less than 11% ash, and up to 60% of the calorific value in a product of less that 8% ash. The bulk of the pyritic sulfur was rejected from the coal as well. Multistage flotation tests showed that the flotation column was able, in a single stage, to produce the best froth flotation product that it was possible to recover from this coal.

Jan 1, 1994