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By M. D. Flavel

My paper relates to bond's third theory of comminution and suggests work be used as a basis for designing crushing and screening plants, this will give more accuracy than existing methods, As stated in the abstract, this paper is only a synopsis of my official paper, many of the questions that might arise in this brief address will be answered by referring to the detail i n the main paper $ Because of the limited time available and the fact that many people here do not need to study the aspects of crushing and screening in depth, i will highlight-those sections of the paper which show how major capital, operating and energy cost savings can be achieved in the process, I will develop the theme in the following manner, Firstly, pointing out, why a new approach is needed to the fundamentals of crushing and screening, Secondly, by setting forth some theory to describe what we are trying to accomplish, Thirdly, by looking at important factors which need to be observed in designing plants and applying machines to comply with this theory, Lastly, i will put forth some ideas on how we might develop this theory to make the industry more efficient, At the outset, i have to say my approach to this process is entirely new, for those used to applying machines and designing plants on existing criteria, they will find this theory easier

Jan 1, 1977

By S. Upadhyay, A. M. Afrapoli

"Fluctuation in market price of mineral products has enforced mining companies to cut down their operating costs. One useful way of reducing operating costs in mining operations is to make optimal operational decisions, incorporating efficient mining fleet management systems (FMS). Over the last 50 years, several types of FMS have been developed and introduced in the mining systems around the world. However, there are two major shortcomings in existing systems. Firstly, none of the existing systems consider effects of the short-term plan on dynamic truck assignment. Secondly, most of the existing FMSs make decisions in a way that optimize a specific objective while ignoring others. Herein, we propose a multi stage and multi objective FMS that deals with aforementioned shortcomings of the currently available systems. The developed FMS, in its upper stage, links semi-dynamic operational decision making process to the short-term production plan by simultaneously assigning shovels to mining faces and allocating trucks to the shovels by implementing its first multi objective decision making model. Then in its second stage, in a real time dynamic decision making process, it assigns trucks to shovels and corresponding destinations by optimizing its second multi objective decision making model. The developed fleet management system has been verified using an Iron ore case study and the results are presented in this paper. INTRODUCTION Open pit mining method is the most common method to mine mineral from the earth. Based on Wetherelt and van der Wielen (2011) there exist 2500 open pit metal mines that are categorized as industrial scale mines. Over all of those, the amount of material handled using truck and shovel material handling system is more than the amount handled by all other systems together (Humphrey & Wagner, 2011).It has been proven by several studies that more than 50 percent of operating cost in a truck and shovel based open pit mining operation is accounted for material handling (Moradi Afrapoli & Askari-Nasab, 2017, Alarie & Gamache, 2002, Ahangaran et al., 2012). Thus, introducing even 1 to 2 percent cut in its material handling cost saves huge amount of money for the stakeholders. Over the last 50 years, two major areas have been identified to cut this cost. On one hand mining industries have been implementing equipment with higher production capacities, and on the other hand, researchers have been developing operations research techniques to make dynamic decisions as close to optimal as possible to deduct operational costs in truck and shovel based mining operations."

Jan 1, 2018

By P. R. Hervey

Quartz is the second most widely used electronic material, with approximately 3,000 tons of single crystals used each year. Virtually all of this material is synthetic; grown with a technique called hydrothermal growth. We will review the basics of hydrothermal growth, the feedstocks for these crystals, and the challenges to improving the growth process. We will also review the processing of these crystals, the markets and applications where they are used, and the global outlook for these markets.

Jan 1, 1999

By R. J. Visintainer, J. M. Furlan

"Due to the time-consuming nature of froth testing in a laboratory environment, practical limitations require the development of a method of applying a single set of performance test data (Visintainer and Whitlock, 2012) obtained for a single froth pump at a given speed to a range of froth pump speeds and sizes, % air content and liquid viscosities. Head, efficiency and flow all vary as functions of both liquid viscosity and air content. As such, it is necessary to develop a technique that can be used to interpolate from existing test data in order to predict froth performance for pumps of various sizes running at variable speeds. Details of the technique developed in order to achieve this goal, as well as the insights gained from analysis of the resulting regressions, are discussed. Additionally, comparisons are made between the performance predictions of this test-derived method and those of the Hydraulic Institute standard for the effects of liquid viscosity on centrifugal pump performance (ANSI, 2010).IntroductionPump performance data (Visintainer and Whitlock, 2012) has been collected for a froth pump using an experimental loop outfitted with an array of pressure transducers, mass flow meters, an inverted U-loop, magnetic flow meter and an assortment of other instrumentation. Experiments were performed on pure water, water and air, pure corn syrup, and corn syrup and air. Data was obtained for % air contents of 0-30% and viscosities of 1- 15,000 cSt at eight specific valve positions (eight different flows as a percentage of best efficiency flow points) and the viscosity was changed by allowing the system temperature to increase during testing. The test pump is a 710-mm diameter impeller, GIW HVF, open shrouded, vented design that has its discharge axis oriented at 45° upward from the horizontal. A schematic diagram of the froth pump test loop can be seen in Fig. 1."

Jan 1, 2015

In this paper, the logic and the capabilities of a long term production planning method for open pit mining are presented. The method is the first attempt in obtaining simultaneous solutions to the four interrelated parameters of open pit mining; 1) the mine life, 2) the specific blocks to be mined each year, 3) the amount of ore and waste to be mined each year, and 4) the ultimate pit limits. An efficient cutoff grade can also be obtained through a sensitivity analysis. None of the existing methods can bring such a comprehensive solution to the problem. A production plan for a real life gold deposit is given to illustrate the logic and the capabilities of the method.

Jan 1, 1993

By Bryson D. Trexler

Slope stability in open pit mines is governed by rock structure, rock quality, ground water conditions, blasting, pit geometry and excavation method. Of these factors, the control of ground water pressures often represents the primary tool to improve slope stability. Production equipment has recently been used to stabilize two slide areas by dewatering using blasthole drills for vertical holes and secondary drills for horizontal holes. This paper describes both of these dewatering programs and contrasts an earlier slope stabilization program that employed a subcontracted horizontal drill.

Jan 1, 1983

By John P. Weir

The coal industry is ever changing. This paper discusses some of the problems which must be faced and the projected economic effects. Challenges include a relatively mature technology, a resource base which has deteriorated significantly in some areas, rapidly escalating freight rates, and a constantly changing regulatory environment, wherein reduced sulfur emissions will probably be required.

Jan 1, 1984

By M. Z. Emad, M. U. Khan, A. ur Rehman

Stemming plugs are used as an accessory in drilling and blasting industry. They supplement conventional stemming material (i.e. drill cutting) with retention of gases in the drill hole that result in better fragmentation of rock and improved explosive utilization. Better fragmentation and explosive utilization along with economic benefits enhance efficacy of the project. Incorporation of stemming plugs in drilling and blasting industry is in exercise for about thirty years. The efficiency of stemming plugs is a key factor in their rising induction in mining industry. Different studies have been conducted on the economic viability of these plugs. The focus of this paper is the selection of stemming plugs for a bench blasting operation and the examination of blasting operation efficiency based on ergonomics and human factors. Three types of stemming plugs were evaluated during multiple blasts at a limestone quarry. Their performance was evaluated using split desktop software. Based on the human factors plastic molded stemming plug (stemming plug-1) was found to be the best among all selected plugs. INTRODUCTION Surface mines and quarrying operations heavily depend on bench blasting to achieve high volumetric targets and production demands. Use of explosives is the most economic method adopted for rock breakage and movement. Extensive research had been performed to enhance explosives energy utilization. This include changing the drilling pattern, application of air decks, stemming plugs, and use of other supportive devices. Optimization of explosive energy has been a major concern in those mines that rely on drilling and blasting operation to carry out main production. Due to continually increasing cost, efficient mining demands, and associated hazards of using explosives, it is necessary to utilize explosives at their best. Efficiency of a blasting operation is generally evaluated by the fragmentation size. From post blast conditions at blasting site to efficiency of processing plant, anything can be affected due to improper blast resulting in bad fragmentation. Better fragmentation is necessity for better operation of the system along with consideration of the safety of operation, environmental issues and related costs. For developing a blast design, an engineer should always attempt to minimize the cost of operation without compromising with acceptable technical and safety necessities [1]. Blast performance is dependent on many different factors associated with the process. These factors have been gauged as blast geometry, explosive specification, and rock mass properties [2]. Similarly, in 2013 Mohammad et al. concluded that fragmentation dynamics depends on blast hole diameter, primer, spacing, stemming, burden, and delay timing for blasting operation [1]. At the work site where this study was performed, blast holes were filled by drill cuttings and muds to help in confining gases. In a blast hole, gas confinement helps in better rock fragmentation along with reduced flyrocks. This practice is most common in many countries including Pakistan. Due to lack of homogenized particle size, the effectiveness of confinement is variable and majorly based on the size of stemming. Extremely small sized drill cuttings often result in hole blow out along with flyrocks from the collar. This improper blast energy will result in poor blast, bad impacts on environment, and reduced operational efficiency. In addition to the stemming material, the length of stemming is also a prime consideration. The decrease in stemming length will increase the quantity of explosive in the blast hole and an increase in stemming material generally improves stemming performance.

Jan 1, 2019

By D. J. A. Chambers, J. M. Wempen, K. D. Koper, M. K. McCarter, K. L. Pankow

"The EarthScope Transportable Array (TA) of broadband seismometers (www.usarray.org) was deployed across southwest Wyoming from November 2007 through May 2009. During this time period the Array Network Facility (ANF, anf.ucsd.edu) detected and located a total of six seismic events near the trona-mining district. This lack of seismicity is atypical compared to coal mines employing similar mining methods. In this study, eighteen months of continuous seismic data from several nearby TA stations are reexamined using conventional and correlation-based methods to detect seismic events. Waveform cluster analysis and epicentral locations are used to discriminate between mining induced seismicity (MIS) and seismic energy generated from surface blasts at nearby coal mines. The locations and magnitudes of the 143 newly detected MIS events are compared to regional subsidence as measured by Differential Interferometric Synthetic Aperture Radar (DInSAR). INTRODUCTION An abundance of natural resources and a favorable political climate have made southwest Wyoming home to multiple large mining operations. Among these operations are five underground trona mines located approximately 50 km west of Rock Springs, Wyoming. The trona mines employ room and pillar, longwall, and solution mining methods over an area roughly 900 km2, and produce a sizable portion of the world’s soda ash (Brown 1995). Historically, in the Rock Springs mining district, several relatively large magnitude seismic events have occurred. These events are thought to have been related to mining activity and have caused notable subsidence (Case 1997). The largest event in the region recorded by seismometers, ML 5.1, has been confirmed as the 1995 Solvay Trona Mine collapse (Pechmann et al. 1995). In addition, blasting at surface coal mines near Rock Springs produces significant amounts of seismicity; approximately 50% of all daytime seismic events in the Mountain time zone from 2007 to 2009 locate near an active surface mine in this region (Astiz et al. 2014). Much of the current research related to surface subsidence and induced seismicity focuses on wastewater impoundment (Ellsworth 2013) and hydraulic fracturing. The observable seismicity in geological injection environments is widely variable and McGarr (2014) has argued that, in such environments, the maximum amount of seismic energy that can be released is proportional to the injected volumes. Like injection environments, in extraction (mining) environments seismicity is highly variable depending on many geological and operational variables (Boltz et al. 2012; Carnec and Delacourt 2000; Fritschen 2010; Iannacchione et al. 2005; Sen 2013) and does not always correlate well spatially with subsidence, a surface expression of extraction at depth."

Jan 1, 2015

By Karin Bäppler

Hydropower produces almost two-thirds of the world’s renewable electricity generation and delivers a major contribution on the ambition of the Paris Agreement and Sustainable Development Goals (SDG) with a range of benefits to society and environment. These include clean and flexible generation and storage in addition to reduced dependence on fossil fuels and avoidance of pollutants. The Limberg III PSP is one of the European projects that addresses the implementation of the UN SDGs. The challenge of the project is the construction of a 770 m long pressure shaft to be excavated with a TBM at an inclination of 42°.

Jun 13, 2023

By John J. Dran

Large mining companies use a number of sophisticated analytical techniques for introducing the element of risk into the valuation of mineral reserve sites. These methods include, but are not limited to, sensitivity analysis, computer simulation, conditional probability, and portfolio theory. Such techniques enable the managements of these large companies to have an awareness of the many possible ramifications of their investment decisions. On the other hand, small mining companies and individuals in the mining business, due to limited financial and technical resources, still rely primarily on single point estimates of the value of mineral reserves. These small miners introduce the aspect of risk only through the application of an appropriate "speculative" discount rate. This paper illustrates the application of a technique for the introduction of risk into investment analysis. The method appears to be most suitable for use by small mining companies and individuals contemplating a large investment in a new mineral reserve site.

Jan 1, 1974

The capability for on-line measurement of the quality characteristics of conveyed coal now enables mine operators to take advantage of the inherent heterogeneity of those streams and split them into wash and no-wash stocks. Relative to processing the entire stream, this reduces the amount of coal that must be washed at the mine and thereby reduces processing costs, recovery losses, and refuse generation levels. In this paper, new approaches for optimal control of the segregation process, using time series models and empirical distributions, are presented and demonstrated using field data.

Jan 1, 1998

By G. Van Weert

Refractory ores and concentrates containing silver tend to form Ag-jarosite during autoclave oxidation. Silver extraction from the oxidation products is therefore low, unless a hot lime treatment step to decompose Ag-jarosite precedes cyanidation. Since silver iodide is very stable but soluble in cyanide solutions, the formation and decomposition of Ag-jarosite in the presence of iodine species was studied. Results indicate that Ag-jarosite formation could be prevented in favour of H3O-jarosite and AgI while oxidizing Ag2S under industrial autoclaving conditions, when the total iodine species to Ag mole ratio exceeded 5. Lower ratios gave proportionally more Ag-jarosite and less AgI. Under these conditions existing Ag-jarosite was also found to decompose in H30-jarosite and AgI.

Jan 1, 1993

By J. Kretschmann, P. Goerke-Mallet, C. Melchers

Mining always leaves a mark behind. Dealing with this legacy is not only a tremendous challenge in Germany, but internationally too. The Technical University Georg Agricola (THGA) in Bochum, Germany, has established a Research Center for Post-Mining. Researchers combine expertise from a variety of technical and nontechnical fields in their quest to shape the post-mining era that completes the mine life cycle. In this respect, the Research Center focuses on four research areas: Perpetual tasks and mine water management, Geomonitoring, Material sciences and site transition. With more than 200 years of successful partnership with the mining industry in Germany and abroad, THGA offers a perfect setting for fresh and sound ideas in order support mining’s social license to operate. The aim of the paper is to describe the Post-Mining Research Center along with exemplary research projects that are of interest to the mining industry globally and to foster technical communication and research networking.

Mar 2, 2022

By A. G. Nitschke, I. Ossenbühl, W. Dolsak, J. Dase

"The authors have successfully developed an innovative rehabilitation concept, which meets actual technical standards and minimizes the impact on the operation of a key conveyor tunnel. A flexible and stepwise ground support rehabilitation program utilized a combination of yielding steel arch sections with grout filled fabric hoses, which represents a fast and safe backfilling support system. The system was developed and successfully installed at Bingham Canyon Mine, the world’s largest open pit copper mine, which also includes numerous underground structures. The mine is owned and operated by Kennecott Utah Copper (RTKC) a fully owned subsidiary of Rio Tinto. The system was implemented at a conveyance tunnel, which was originally designed as a railroad tunnel, but was re-commissioned and is currently used as a conveyor belt tunnel to transport ore from the open pit to processing facilities outside the mine. The existing structure showed signs of overstressing due to movements in the surrounding rock mass, which had to be addressed with a yielding support system in order to provide safe access into the tunnel. However, the impact on the conveyor belt operation due to support installation was to be limited to the bare minimum. Keywords: rehabilitation, yielding support, mining, stabilization, and grout filled fabric hose.PROJECT DESCRIPTION The C6 Tunnel is considered a critical asset for the operation of the Bingham Canyon mine as it comprises the standard route for transporting crushed ore from the open pit to the processing facility on a continuous conveyor belt system. The C6 tunnel was originally built as a railroad tunnel. Construction was completed in 1959. The original horse-shoe shaped cross section of the tunnel was 18 feet wide and 24-1/2 feet high [8]. The tunnel length was approximately 18,000 feet. During its service life, the railroad tunnel has undergone several transformations. The length of the tunnel towards the Bingham Canyon pit was shortened over the course of mining operations and the railroad tracks in the tunnel were removed. The invert was partially backfilled (3 feet typical) and a 72 inches belt conveyor was installed. Currently, the C6 Tunnel is nominally only approximately 21 feet high and 15,000 feet long. Ground Support and Rehabilitation Measures prior to 2014 The C6 tunnel was mined mainly with conventional mining methods, using drill & blast as the typical one. However, the weak geological sections, such as those encountered in the Fortuna fault, were excavated by shaping and chipping with machine-held moils [8]."

Jan 1, 2015

By Dipl. -Ing. Mertens

Gentlemen: I am pleased and regard it as a priviledge to give you a report on rapid roadheading with heading machines in the coal mining industry of Western Germany. Importance of Heading Operations in the West German Coal Mining Industry Every year about 770 km of headings are driven In the seams of the West German coal mines, most of them gate roads, the rest rise headings, to open new faces. In thick seams the heading operations are carried out entirely in the coal, in thin seams the country rock has to be ripped. The total length of 770 km corresponds to a rock volume of roughly 9.5 million m3; this figure underlines the importance of the heading operations in the coal mining industry of our country.

Jan 1, 1970

By L. Meier, M. Dennis, J. Schieffer, K. Murray

"INTRODUCTION Contrary to popular belief, Arizona State Trust land is not public land. All uses of the land must benefit the Trust, a fact that is considered with the review of each application received for sale, lease, or permit. This includes applications for activities ranging from commercial development to recreation. In 1863, the Territory of Arizona was established by an act of Congress. This act reserved sections 16 and 36 in each township to be held in trust for the benefit of the common schools. Later, the Enabling Act of 1910 allowed the Territory of Arizona to prepare for statehood. This act reserved the additional sections 2 and 32 of each township for the common schools and granted another 2,350,000 acres to be held in trust for other beneficiaries. In all, Congress granted the State of Arizona almost 11 million acres. The State was to manage those lands and maximize revenue for 13 separate beneficiaries. To meet this mandate, the State established the Arizona State Land Department (ASLD) in 1915. During fiscal year 2015, the ASLD contributed $136 million to the permanent fund, bringing the total value to over $5.1 billion, through the sale and leasing of the land and natural products which includes minerals. The current inventory of State Trust lands includes 9.2 million acres representing about 12.7% of the State.The ASLD Minerals Section manages the exploration, development, and leasing of mineral products on State Trust land. We are not a regulatory agency, but a department guided by our fiduciary responsibilities to the Trust. Our mineral programs include: Exploration Permits, Mineral Leases, Mineral Material Leases, Geothermal Leases, Oil & Gas Leases, and Special Land Use Permits. INDUSTRIAL MINERALS ON ARIZONA STATE TRUST LAND Industrial minerals fall under the category of either Mineral or Mineral Materials Leases. Common industrial minerals found on Arizona State Trust land include potash, limestone, gypsum, salt, specialty clays, zeolites, crushed stone, and sand and gravel."

Jan 1, 2016

By William Gleason

With its 2011 acquisition of rival equipment company Bucyrus International, Caterpillar added underground mining and large shovels to its line of products and further solidified its standing as the leading mining equipment manufacturer in the world with solutions for every aspect of mining. When Caterpillar spent $8.8 billion to acquire Bucyrus, the global mining business was flourishing, as mining companies around the world worked to keep up with demands for nearly every commodity. Flash forward to 2013, and the global mining landscape looks very different. Lower demand for raw material from China and India and falling commodity prices have forced most mining companies to pull back on their production. The reductions from the mining industry have hit equipment makers like Caterpillar and Komatsu hard. In October, Caterpillar reported that its quarterly earnings had fallen 44 percent. The changing conditions have also changed the narrative from Caterpillar and other equipment makers to customers from offering solutions to move the most tons per hour, to now offering solutions for the lowest cost per ton. In September, Caterpillar hosted some of its mining customers and the trade press at its Tinaja Hills Demonstration and Learning Center near Tucson, AZ to talk about its range of products, from its MineStar System designed to help increase efficiency through better equipment management and planning, all the way up to the massive Cat 7495 and 7495HF electric rope shovel lines acquired through the Bucyrus takeover

Dec 1, 2013

By Jacques B. Wertz

Although fracture intersections and "domes" seem at a number of places to be the basic structural combination for the occurrence of a mining district, of the porphyry-copper type particularly, this situation is, of course, not always to be expected. For instance, the group of mines comprising Superior, Ray, Miami, Globe, Christmas appeared from the beginning of these structural studies as typical exceptions, and there are others. One had to expect additional parameters to allow for any mineral concentration to occur. One of these apparent parameters is here considered. From the result of stratigraphic studies related to ancient formations in Southeast Arizona, the Martin limestone (Devonian in age) was retained as having a possible relationship with the structure-economic studies in progress, as evidenced for instance by the mineralized O'Carroll bed located at the base of the Martin. This limestone formation has been rather extensively investigated in the past and there are many known sample localities. For this work, the isopach map was drawn by computer to insure more objectivity and, in addition to the available data points, a number of dummy points with a zero value were added around the assumed form-

Jan 1, 1971

By I. K. Gilmore

Texasgulf Inc. currently operates an open pit phosphate mine in the central coastal plain of North Carolina. The area of phosphate deposition lies within the Aurora Phosphate district which consists of an embayment which is in the center of the Neogene phosphate deposition. A variety of solid and liquid fertilizer products are produced at the Texasgulf complex. One of these products is known as North Carolina Natural Phosphate (NCNP). New potential for use of unacidulated natural phosphate, now exists in regions with acid soils due to the discovery of the findings from recent research, cost advantages, and moves to reduce chemical inputs.

Jan 1, 1995