Search Documents

By Jon A. Hummer, MICHAEL R. SHAHAN, Aleksandar D. Bugarski, Shawn Vanderslice

A study was conducted in an undergroundminewith the objective to identify, characterize, and source apportion airborne aerosols at the setup face and recovery room during longwall move operations. The focus was on contributions of diesel- and battery-powered heavy-duty vehicles used to transfer equipment between the depleted and new longwall panels and diesel-powered light-duty vehicles used to transport personnel and materials to various locations within the mine. Aerosols at the setup face were found to be distributed among diesel combustion-generated submicrometer and mechanically generated coarse aerosols. According to the data, the submicrometer aerosols downstream of the setup face were sourced to diesel exhaust emitted by vehicles operated inside and outside of the panel. Depending on the intensity of the activities on the panel, the outby sources contributed between 12.5 and 99.6% to the average elemental carbon mass flow at the setup face and recovery room. Extensively used light-duty vehicles contributedmeasurably to the elemental carbon concentrations at the setup face. The number concentrations of aerosols downstream of the setup face were associated with aerosols generated by combustion in diesel engines operated in the shield haulage loop and/or outside of the longwall panels. Entrainment of road dust by diesel or battery-powered load-haul-dump vehicles operated near the measurement site appears to be the primary source of mass concentrations of aerosols. The findings of this study should help the underground mining industry in its efforts to reduce exposures of miners to diesel and coarse aerosols.

Apr 14, 2020

By T. R. Ellis

Many appraisers/valuers believe that the only valuation method available within the cost approach category for real property appraisal is the depreciated replacement cost method. Some valuation and financial reporting standards setters also believe the same. This paper introduces the minerals appraiser to a number of useful methods for mineral property appraisal that are based primarily on the principle of contribution to value, the predominant economic principle in the cost approach. Most of these cost approach methods discussed are primarily for use in valuation of exploration tracts and resource properties that have no defined reserves. However, the powerful rural cost method can be used to calculate the contribution of categories of resources, reserves and other property components to the value of a mineral property. This method can be applied to mineral properties at all stages of development, including producing properties. The author reasons that standards and regulations pertaining to real property valuation should be modified, and underlying principles should be expanded, so as not to inhibit appropriate application of these cost approach methods.

Jan 1, 2011

By Joseph M. Chelini

Today, the two major operating costs of rubber tired off-road equipment are diesel fuel and tires. Mine Management has minimal control over the ever accelerating diesel fuel costs. However, they can exercise control over abnormal tire costs. Fortunately, with available technology and cost analysis methods, experience shows us the outlook for controlling tire costs is encouraging. Most earthmoving operations using off-road, rubber tired haulage and support equipment have abnormally high total tire costs. These costs, utilizing Tire Information Management, have been reduced more than 30%; 20% can often be guaranteed. Management Apathy on the subject of tires in a complex mining operation perhaps can be understood, but management apathy applied to an abnormally high operating cost, of which tires are, begs for a solution.' Tires have been professionally neglected for many years in most mine operations. This is exemplified in the January, 1982 issue of Mining Engineering by Charlie Son in his article Reducing Earthmoving Tire Costs. He compared the efforts to improve diesel engine costs to the same efforts given to earthmover tires.

Jan 1, 1983

By David Crouthamel, Raymond Henn

"The need to fill the void space or annulus created between an excavated tunnel or shaft and the final lining system has long been a requirement in underground construction. Most of those types of voids are created as a result of employing the two pass tunneling lining method. Filling of this void is called backfilling. For many years the materials used as backfill were primarily reinforced and non-reinforced concrete, sanded grout, neat cement grout, or blown-in sand/pea gravel. However, in the past 20 years the use of cellular grouts/cellular concrete as the backfill material has greatly increased. Most cellular grout is made of a mixture of water, Portland cement (with or without the addition of fly ash), a foaming agent and admixtures such as a water-reducer or superplasticizer.It is the authors’ preference to use the term cellular grout as opposed to cellular concrete since by ACI Concrete Terminology an ACI Standard (ACI CT 13), concrete contains aggregates. Normally cellular grout does not contain sand (finite aggregate), but almost never contain course aggregates.The authors believe there are several reasons for this increased use of cellular grout as backfill, such as:• The increase utilization of the various trenchless tunneling methods. Tunnels constructed using trenchless method tend to be smaller in size, excavated diameter or cross sectional area. Making man-entry for placing backfill from inside the secondary liner, utilizing pre-installed grout posts, more difficult if not impossible. It is these workspace restrictions that are the drivers as to when to utilize grout ports installed during the pipe/liner fabrication versus grout delivery pipes installed within the void/annulus space.• The ability of cellular backfills to be pumped and flow longer distances.• The unit weight of cellular grouts can be controlled by mix design and generally can range from 560 Kg/m3 (35 lbs/CF) to 1040 Kg/m3 (65 lbs/CF)."

Jan 12, 2017

By İsmail İnce

The existence of water is one of the most effective factors in deterioration of natural building stones. In the process of deterioration, capillary water absorption is the most significant procedure of water penetration into the building stones. Pyroclastic rocks have been widely utilized as building stone especially in historical buildings and monuments since ancient times in the Central Anatolia in Turkey. Nowadays, this type of rocks is used in the restoration of historical buildings as well as in the construction of modern buildings. Pyroclastic rocks are highly susceptible to deterioration process. Capillary rise has a significant influence on water penetration into building stones. Therefore, it is quite important to identify the factors affecting the values of capillarity, capillary rising speed, and capillary rise that define capillary water absorption in these rocks. To this end, pyroclastic rock samples in different textures were compiled from the Cappadocia region, in Central Anatolia. First, petrographic, mineralogical, geochemical, physical, and pore diameter distribution properties of the samples were determined in the laboratory. Then, capillarity values with capillary rise and capillary rise speeds dependent on time were established. Based on the data obtained, correlation coefficients between matrix percentage and capillary water absorption rate and capillary rise values of pyroclastic rocks were calculated and found to be as 0.850 and 0.891, respectively. Thus, the article proposes a new empirical equation to practically calculate the capillary rise value depending on the matrix percentage (MP) and median pore diameter (MPD) values.

Nov 30, 2020

By William G. Pariseau

Safety of mine ramps begins with an analysis of stress that almost certainly must be done numerically to take into account ramp geometry, route geology, rock properties, and pre-ramp stresses. The popular finite element method serves analysis purposes quite well. As a practical matter several obstacles to implementation need to be addressed including collection of rock and joint properties along the proposed ramp route, selection of ramp type, and specification of cross-section shape, size, and route grade. Additionally, stresses along the proposed route must be specified, preferably from in situ measurements. One need not be an expert in numerical methods to proceed to ramp design, although a background in mechanics of materials and rock mechanics is essential, and a first course in numerical methods is quite helpful. The necessary software is easily brought to the design task, more accurately, to the task of design evaluation. This software also addresses other important mine design problems including design of safe (1) main entries in stratified ground, (2) barrier pillars, (3) bleeder entries, (4) inter-panel barrier pillars, (5) room and pillar mines, (6) shafts, and (7) “tunnels” (Pariseau 2022).

Feb 1, 2024

By Dominick Mandalari, David Mast, Heather Ullinger, Juan Granja, Amanda Foote

The City of Akron will construct the Northside Interceptor Tunnel project, a U.S. EPA/ DOJ CSO Long Term Control Plan Project. The system will provide at least 10.3 million gallons of storage in a 16.5-foot finished ID and 6,660-foot-long rock tunnel. The system will reduce both overflow volume and number of overflow structures on the Cuyahoga River. The project includes deep drop shafts and more than 3,000 linear feet of 48 to 96-inch I.D. sewers installed by trenchless construction methods. This paper will discuss the project background, ground conditions, and other challenges overcome during the design phases.

Jun 13, 2023

By W. H. Renison

This paper will discuss the operation and maintenance of Molycorp's Quests Mine ore conveyor system. The 1.2 m wide, steel cable-reinforced conveyor belts are capable of transporting 1089 kt/h of ore over a belt line distance of 3124 m with a vertical rise of 518 m. A portion of the conveyor runs in a 2057 m long underground decline on a 10° slope. Six 448 kW motors power the main 1.2 m wide belts.

Jan 1, 1984

By R. R. Klimpel

The efficiencies of plant scale comminution processes are often evaluated by various indices that are calculated and/or measured somewhat independent of the performance of any associated downstream froth flotation processes. In order to compare some specific comminution factors such as energy utilization, media consumption, equipment utilization time, etc. comparisons of comminution efficiency independent of flotation behavior are appropriate. However, as more and more detailed plant level information is gathered on the joint and highly interactive nature of comminution and froth flotation, it is becoming increasingly obvious that knowing and using simple efficiency indices are not enough. What is needed are more performance related measures of the efficiencies of the combined size reduction -froth flotation system for effective plant level economic optimization to occur. The purpose of this paper is to present some examples of important interactions that influence the joint efficiencies of size reduction and froth flotation processes.

Jan 1, 1998

By Keith Whitworth

The USSR, over the last 20 years, has continued to increase its out-put year by year and it is now almost four times what it was at the end of the Second World War. In 1975, it exceeded 700 million tons of run-oi-mine coal (all ranks) which amounts to over 20 percent of world output. This rapid progress has been due to modernization of the industry, by means of increased mechanization and automation and the development of new machines and systems for underground workings and by the expansion of open-pit workings and the development and implementation of larger earthmoving machines.

Jan 1, 1977

By R. Pinksen

The IOC Mining and Operations Departments expressed an interest in reducing the amount of oversize material (>1.0 m x 1.0 m x 1.0 m; 39 inches x 39 inches x 39 inches) being produced and its subsequent downstream effects including in-pit sorting and reduction, damage to mobile equipment, and significant delays in the loading pockets and the primary crushers. To achieve this goal an oversize reduction project was undertaken by the mine and to date has significantly improved upon baseline measures. One key approach used to reduce the amount of oversize was the implementation of thicker emulsion. The introduction of a thicker emulsion provided more resistance to the forces created by dynamic water and reduces the infiltration of the emulsion into the cracks and fissures of the rockmass. Reduced amounts of oversize and more consistent fragmentation throughout the muckpiles has been a result. Additionally, a significant reduction in nitrates leached into the mine water discharge has been realized. To determine the effectiveness of the oversize reduction project, IOC used a of first-of-kind technology to assess fragmentation presented to the shovel at the digging face. A Digital Vision System (DVS) was installed on one of the shovels to capture images that were stamped with GPS locations. A large population of digital images were analysed to produce a robust fragmentation distribution baseline that was used as one of the mine key performance indicators (KPI). Changes to blasting practice were subsequently measured against the baseline KPI to assess effectiveness.

Jan 1, 2011

By H. Lyn Bourne

This is the sixth annual tabulation that gives mineral royalty information. This tabulation, like the previous editions, includes all of the earlier data plus more than 100 new entries. In addition to the royalty information, some entries show the cost of purchased reserves. An article in the December 1984 Kentucky Coal Journal could have far reaching applications. It explains that a banking firm examined the "reserve risk" as one of six factors for analysis when financing a coal project. The firm concluded that coal reserves in Kentucky are worth an average of $0.29/t ($0.26 per st) in-place. The banking firm based this in-place value on its examination of more than 50 leases. In-place value is especially important when trying to establish a mineral value for a given deposit. Ernie Lehman wrote to this author after last year's column appeared and he quoted the lease rates for lead and zinc on federal land. He states, from first hand information, that the leases are based on a percentage of net smelter return as follows: 4% for the first five years, 4.5% for the next five years, and 5% thereafter. The figures used in last year's column ($ per st) came from dividing reported royalty income by reported production. The information reported last year merely translates the results of the net smelter return (as written in the lease) to royalty income per ton to the US Government for the various years. Statistics from the Minerals Management Service of the Federal Government show that oil and gas account for 40% and 53%, respectively, of the Federal royalty income. Coal accounts for about 4% and all other minerals, the remaining 3%. Oil and gas leases are mostly at 12.5%. Most of the coal leases are at 12.5% for surface mining operations and 8% for underground mining. Many of the other commodities are leased at 5%, which has been true for decades. Relative to Federal leases, this year's table shows some percentages and some costs per ton. This was done to give information about the leases and also to show income produced by various commodities. Note that some commodities have a variation in $/ton even though the royalty percent is the same. These variations result from a combination of factors that influence the value of a mineral commodity. The same caveats that have appeared in previous columns relative to factors that influence the value of reserves are restated. The data in the table serve as a general reference and are not intended to present an absolute scale of reserves costs. Several factors influence the value of any mineral commodity. The factors include: • location/transportation (especially significant for most industrial minerals); • market conditions both for the commodity and the company acquiring the right to mine it; *quality or grade of the deposit as it reflects the amount of processing/beneficiation necessary to produce the finished product; and • legislative restrictions and conditions for mining a given material at a given site. These and other factors will significantly influence the cost of reserves. The table shows the range of royalties and the variations in the basis of computing the fees. In a few instances, it gives the cost of acquired reserves based on purchase price and quantitative estimates of the material in place. The table lists the commodity in column 1, and the subsequent columns give the location - either by state, US geographic area or Canadian province; the cost - R for royalty and P for purchased cost; and the year in which the lease or purchase agreement occurred. The last column offers either comments or gives a footnote number for more information. The cost column requires more explanation. The units may refer to cubic yards (/yd), cubic feet (/cu ft), tons (/T, 2000 lbs) or acres (/A). 1 cu yd = 0.7646 m3 1 cu ft = 0.2832 m3 1st=0.9078t 1 acre = 0.4047 hm or m2 In several cases, the royalty is a percentage of the sales price of the finished product and is levied against either the amount produced or the amount sold. We thank those who contributed information for the table: G. Anderson, B. Brown, R. Ganis, K. Hauser, E. Lehman, and S. Sims. Their help is appreciated as are the contributions by those who asked to remain anonymous. This column requires additional information each year. That data must come from people in the minerals industry who have royalty information. What appears in the table is only a very small fraction of the cost information relative to the various commodities and the geographic areas for which there is royalty information. If you find this column of interest and possess information write the author at the address given in the author's box or call 313-462-0005.

Jan 7, 1988

By Nikhil Dhawan, SHAILA MIR

Consumer preference for ever-higher laptop performance coupled with laptops’ declining lifespans make them a significant contributor to electronic waste. An in-depth evaluation of elemental composition and distribution is important for determining metal recovery potential and sustainable recovery processes. In this work, the characterization of individual components of laptops is studied for the systematic identification of important elements and for streamlined and structured recycling, to reduce processing steps and improve economics. A process flowsheet highlighting various recycling routes by targeting metals and various components is also proposed.

By J. G. Groppo

Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 pm) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20 percent level moisture will be an important step in successful implementation of the advanced cleaning processes. This study is a step in the Department of Energy's program to show that ultra-clean coal could be effectively dewatered to 20 percent or lower moisture using either conventional or advanced dewatering techniques. The main focus of the pilot plant study was on proof-of-concept testing of a dewatering technique for a fine clean coal product. The coal industry is reluctant to use the advanced fine coal recovery technology due to the non-availability of an economical dewatering process.

Jan 1, 1997

By L. G. Hagenbuch

Several factors need to come together in creating an integrate mining equipment dispatching system. At the hub of these factors ace the central dispatching formulas. This paper details the development of these central dispatching formulas and explores the combining of these formulas with other elements to create an integrated dispatching decision. WHY DISPATCHING? Truck dispatching implies and in reality should equate to mine equipment efficiency. Good truck dispatching will yield good mine equipment efficiency while poor truck dispatching will yield the alternative. Truck dispatching can either be automated through a computerized, process or it can be manual. Every mine with haul trucks has a truck dispatching system whether it is recognized or not. Even a system wherein the hauler operators determine where they are going for their next load is a truck dispatching system.

Jan 1, 1987

By Northcutt Ely

My topic today is our Nation's interest in the minerals beneath the oceans. I will state what I think should be our objectives, the means available to attain these objectives, and the obstacles to their accomplishment. It is possible that as early as this year of 1969 our country must make policy decisions on this subject, and that these, once made, will be almost irreversible. Two factors are hastening an. early decision. First, the 1958 Convention on the Continental Shelf becomes eligible for amendment after June 10, 1969, if the Assembly of the United Nations so decides. Second, the United Nations has created a permanent committee of 42 nations, which was preceded by an ad hoc committee of 35 nations, to study the question of the peaceful uses of the seabed "beyond the limits of national jurisdiction. While these measures purport to deal with the creation of a regime to govern mineral development on the deep sea floor beyond the limits of the jurisdiction of the coastal nations, it has become clear that the urgent issue is the extent to which this future regime shall acquire jurisdiction over the mineral resources of the continental margin, and receive royalties therefrom. This brings the proposal into potential collision with the interests of the coastal nations under the 1958 Convention on the Continental Shelf, including, of course, the United States.

Jan 1, 1969

By Joe B. Rosenbaum

Fine-sized mineral wastes discarded by ore milling plants require stabilization to prevent air and water pollution. Methods devised for achieving this stabilization include physical, chemical vegetative, and combination procedures. Although vegetative reclamation is preferred to physical and chemical stabilization, it is difficult to achieve because the wastes are sterile, contain deleterious inorganic salts, and lack the essential nutrients and physical characteristics required for sustaining vegetative growth. Nevertheless, recent research has developed methods for producing vegetative growth on all but excessively acidic, basic, or saline tailings at costs ranging from $100 to $650 per acre. This report summarizes effective procedures developed for vegetating average tailings, the cost differential between the various methods, and suggests procedures that may be applicable for achieving stabilization of pyrite-containing wastes that may oxidize and become excessively acidic. The use of buried layers of sewage sludge to prevent this acidification is discussed.

Jan 1, 1972

By E. Stemn

Incident investigation is of utmost importance in most high-risk industries. This study was undertaken to study the content of past investigation reports to determine the effectiveness of the incident investigations. The study uses a semi-quantitative method to assess the effectiveness of incident investigations in the Ghanaian mining industry by evaluating the quality of past investigation reports. The assessment tool consists of 5 elements with several indicators and rating scales for assessing the quality of an investigation report as a measure of the effectiveness of the investigation. The method was applied to 304 investigation reports of 3 Ghanaian large-scale gold mines, and the results correlated with incidence rates of the mines to determine if any relationship existed. The results showed that the mines differ significantly in the quality of their investigation reports, suggesting differences in the effectiveness of their investigations. In addition, the incidence rates of the mines negatively correlated with some elements of the assessment tool. In general, the method was found useful and revealed areas where improvement is needed. INTRODUCTION The importance of learning from incidents is well documented in the literature. For instance, some scholars regard learning from incidents as important for improving safety [1,2]. Thus, many organisations spend considerable resources in identifying lessons from incidents and subsequently on the process of improvement that follows the identification of lessons. It is therefore important for such organisations to determine the effectiveness of their learning from incidents processes, in order to identify specific areas where improvements are needed, so that interventions can be as specific as possible. The learning from incidents process models the plan-act-check-do approach of management systems, often consisting of four major stages, namely; data collection and incident analysis, planning interventions, implementing interventions and follow-ups and evaluation [3,2]. The investigating and analysis of incidents have been regarded as one of the vital stages of the learning process since it is the stage where lessons are identified [3,2,4]. It has also been noted elsewhere in the literature that results of the previous stage of the learning process are important for the next stage [3]. For example, ineffective incident analyses could result in the planning of ineffective remedial measures. One of the primary aims of incident investigations is to identify lessons from previous incidents which when implemented can prevent future recurrences or minimise the effects of future incidents. There is thus the need for organisations to assess the quality of their investigations periodically since it is one of the means they adopt to improve safety and the quality of remedial measures to some extent depends on the effectiveness of the investigations. Although previous studies [5,2] have assessed the effectiveness of the learning process, and some aspects of the learning process, such as incidents reporting, there is less focus on the effectiveness of incident investigations. The research described in this paper was therefore conducted to contribute to this gap, focusing more closely on incident investigation reports.

Jan 1, 2019

By Dafydd Chandler, Milissa Hirst, Charles Hurst, Gary Snyder, Leszek Glodkowski

The Delaware County Regional Water Quality Control Authority (DELCORA) will be adding tunnel infrastructure to its wastewater conveyance system. This program involves the construction of a conveyance/storage tunnel and related facilities. The proposed 12- foot to 14-foot (±) finished diameter, TBM mined deep rock tunnel spans over 8.5 miles and lies approximately 80 ft-120 ft below the surface. The system is connected to the surface by at least five vertical online shafts and one offline shaft with associated 800ft long adit. This paper provides project details including data on the geologic conditions in which the tunnel will be constructed.

Dec 1, 2022

By R. V. Ramani

Demands on available lands will continue to increase due to the projected increase in population and industrial expansion. Though there is an upper limit on the available lands, the multi-use nature of the lands will make it possible to meet these demands. However, this will not happen without adequate planning. Land uses can be broadly categorized as non-renewable and renewable. Lands with mineable resources can be dedicated at some point in time to the extraction of resources. Such a dedication, however long-term, is only temporary because of the non-renewable nature of the mineable resources. Implied here is that the land will be available before and after mining for other uses. Planning for such lands must have the objective that, as far as practicable, no non-renewable uses are pre-empted and no renewable uses are permanently destroyed. The primary aspects of this planning process will be addressed in this paper, These aspects include a discussion of planning responsibility, data needs and availability, the integration of mine planning and post-mining land use planning and a long-term plan for resource conservation and utilization. Minerals, together with agriculture and forestry products, are the primary sources of wealth. Therefore, to avoid land development that may pre-empt future mineral resource utilization, the local planning groups must be aware of the mineralization and mining potential. Much work needs to be done to identify and characterize the mineral resources. Even more work is needed in land use planning for lands with mineral deposits.

Jan 1, 1982