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By A. Lyndon

Vertical and lateral load tests were carried out on two 13 m deep bored cast-in-place instrumented piles, socketed into weathered sandstone. The first pile, 1200 mm in diameter, was loaded vertically to a maximum of 16000 kN and then loaded to failure under lateral load (1900 kN). The second pile, 1500 mm in diameter, was tested under lateral load up to a maximum of 2400 kN. It was found that the deflections of the 1200 mm pile were more than twice those of the 1500 mm pile under similar loads. The soils on the site are not easily tested in the laboratory, or by conventional insitu site investigation techniques, parameters needed in design can only be reliably obtained from pile test results. In this report shear moduli are back analysed from the vertical load test and the two lateral load tests. For these similarly installed piles very different design parameters were determined from the lateral load tests, the only known major difference between the piles being that the 1200 mm pile was loaded vertically before it was loaded laterally. Changes in G values needed to match performance under vertical load if applicable to lateral loading could have accounted for a significant amount of the difference.

Jan 1, 1989

By L. C. IlsLey, J. W. Paul, E. J. Gleim

Flame safety lamps have been used in gaseous mines since the Davy lamp was introduced, more than 100 years ago. During the last decade the flame safety lamp has been rapidly replaced by the electric lamp as a device for illuminating the miner's working place; in the United States the electric cap lamp has been widely adopted. For example, in 1911 approximately 45,000 flame lamps and no electric lamps were being used in the Pennsylvania bituminous mines, which were then producing 35 per cent of all the soft coal mined in this country; by 1918 the flame lamps had decreased to 17,000, whereas electric lamps-mostly of one maketotaled nearly 48,000. In Great Britain during the same years the total of 723,934 flame lamps decreased to 590,185 and the electric lamps gained rapidly from 4,298 to 156,521. No later reliable figures are at hand. However, before the flame lamp becomes obsolete, it is fitting that the Bureau of Mines compile a permanent record of a device which has served the mining industry for more than three generations, and not only made possible the development of entire districts that otherwise could not have been worked but undoubtedly saved the lives of thousands of underground workers. Flame safety lamps are capable of doing more than the name indicates. First, under normal conditions, they can be used in a mine atmosphere that contains an explosive mixture of gas and air without great danger of exploding such a mixture, though such use of a flame lamp should not be permitted. Second, to an experienced man they indicate percentages of gas much lower than the explosive limit, and thus can be used to indicate to workers the approach of an unsafe condition in the mine atmosphere. Third, flame lamps will not burn in an atmosphere greatly deficient in oxygen, and they therefore warn the users of such deficiency in time to withdraw to a place of safety. Flame safety lamps are still used rather widely in the United States for general illumination and to a still greater extent for detecting gas. Many coal-producing States require fire bosses to use these lamps in gaseous mines, and the regulations of several States specify that a gIven number of such lamps be kept available for emergency service.

Jan 1, 1924

By M. Kuchta, A. Newman

LKAB’s Kiruna Mine, located in northern Sweden, produces about 24 Mton of iron ore yearly using sublevel caving. For efficiency, the mine must deliver planned quantities of three ore products. We use mixed integer programming to schedule Kiruna’s operations, specifically, which production blocks should be mined, and when they should be mined to minimize deviations from planned production quantities while adhering to mining restrictions (e.g., sequencing). A new production block database and a well-formulated mixed integer programming model dramatically reduce the size of the original problem; in less than ten minutes we generate five-year schedules with time fidelity of months.

Jan 1, 2002

This paper is in two parts. The first part provides background to coal in New Zealand, information on Solid Energy the Company and details of the resources, mines and products of the company. This part of the paper is intended for people who have limited knowledge of the New Zealand coal scene. The second part of the paper focuses on developments underway in New Zealand and discusses planned or possible changes and opportunities. This paper was first presented at the Coaltrans Asia Conference in June 2000.

Jan 1, 2000

By P. James

"INTRODUCTION Control of target stream acidity is widely used in MIW (mining influenced water). Tailoring pH (a measure of acidity) finds application for controlling key chemistry in both process and waste streams. Traditional lime addition for neutralization and precipitation is most often used but has high reagent costs and results in large amounts of mixed metal sludge requiring costly disposal. A new adaptation of BPS’s patented DEMET™ technology (Dynamic Electrolytic Metal Effluent Treatment) platform offers a potentially improved and “reagentless” alternative to traditional chemical addition for pH adjustment. Electricity rather than chemical addition utilized in BPS’s proprietary approach controllably tailors target stream pH. The method offers a simple, low-cost processing technique yielding cleaner treatment chemistry. BPS’s “green” approach may yield lower operating (OPEX) and life cycle costs and significant reductions (up to 50%) in sludge generation compared to conventional lime treatment. It can also allow new opportunities to generate revenue via selective recovery of valuable processing byproducts. Specific savings and revenues depend on the target site chemistries, details, and processing goals. A more detailed discussion of the process and its operational principles may be found in Reference One.[1] Here application of the BPS treatment to POx (Pressure Oxidation) leaching as an alternative to traditional chemical addition is examined. An example operation process flow for gold mining is considered.[2] Promising processing points for potentially replacing conventional processes with DEMET are noted. The possibilities for lowering OPEX costs, lessening sludge creation, and capturing various valuable byproducts and residuals are examined. Financial life cycle benefit estimates of the principal gains provided by DEMET application to the example operation are noted. Extension and generalization of the analyses to a wider range of scenarios is explored."

Jan 1, 2016

By R. Ordóñez Olivares

This manuscript focuses on the design and development of steels for the railroad industry and methods of testing them. Here are summarized the results of research focusing on alloy development and design, with particular focus on advanced rails and wheels. The high-performance steels are characterized for their mechanical and service characteristics. The relationship between properties and cleanliness is discussed and compared to the regular railroad steel. Some of the tests presented are standard tests that are complemented with the nonstandard test recommended by the Association of American Railroads (AAR) and recommended modifications of this. The paper presents the results of metallurgical analysis, mechanical, and residual stress tests. The laboratory methods include microstructure, residual stresses, tensile, hardness, fracture toughness, and microcleanliness tests.

Jan 1, 2013

By W. C. Peters, M. W. Pullen, C. A. Bays

During the past three and a half years considerable improvement in the techniques of solution extraction of salt has been made by the use of wells which are cross-connected by hydraulic fracture at the base of the salt. Fracture is initiated by the application of hydraulic pressure. Underreaming and perforating techniques are used to control initiation. The fracture is then extended by continuous pumping until a pressure communication is obtained. Pressure communication is followed by washing-through to obtain a low-pressure connection. Well construction using non-shrinking cements that will bond with the salt and with associated strata is essential to the process. The connecting procedure described permits solution to attack the salt deposit from its base upward, thereby permitting greater recovery, fewer well repairs, better saturation of brine, and overall economy of development and operation. The fracture method of cross-connection requires special pumping of the fluid and is limited by present experience to initial well spacings up to about 1200 feet. The method has been used in bedded salts and is applicable for wells in salt domes. Since spring of 1956, new developnents in salt extraction wells have followed procedures substantially different from those in prior use. Although multiple well systems, connected either by the natural consequence of the solution process or by undercutting under protective pads, have been used previously, the past three and a half years have brought about new designs and new operation procedures based on cross-connection of the wells using hydraulic fracture. To date these techniques have been applied largely in the bedded salt deposits of Michigan, Ontario, Ohio, West Virginia, and New York. To the writers' knowledge they have not been used in salt dome wells. The methods have not yet been in use for a sufficient period to permit any statistical comparison with the older methods. It is evident from experience to date that the methods result in higher recoveries, lower capital and operating costs, better saturation of produced brine, reduced well maintenance and repair, and in considerably fewer production units to insure

Jan 1, 1961

By Jayant Khambekar

In a typical mining operation, run-of-mine (ROM) ore is crushed and screened to achieve a desired particle size distribution and then fed to processing equipment for further refining. For an operation to be profit-able, the ore handling system from the mine face to final product loadout must be reliable. However, the handling system components do not always perform as expected and production problems related to material flow occur. These problems include flow stoppages, limited live storage capacities, uncontrollable flow, segregation, spillage and dust emissions. These result in lost production, excessive maintenance, safety and environmental issues, and even structural failures, in some cases. Flow patterns Flow problems and their solutions can be best understood by first learning how bulk solids flow. As bulk solids discharge by gravity from a storage system, primarily two types of flow patterns can develop: funnel flow and mass flow. Figure 1 shows a schematic of these two flow patterns. In funnel flow, only a portion of the material is in motion during discharge, which flows toward the outlet through a channel that forms within the stagnant material. Funnel flow occurs when a hopper is not sufficiently steep and smooth to ensure flow along the walls or when the outlet is not fully effective. In mass flow, all of the material is in motion whenever any is discharged ? there is no stagnant material. Mass flow occurs when the hopper is sufficiently steep and smooth to ensure flow along the hopper walls. Shallow valleys are not permitted and the outlet must be fully effective. A third type of flow pattern, called expanded flow, can develop when a mass flow hopper (or hoppers) is placed beneath a funnel flow hopper or bin. The mass flow hopper is designed to activate a sufficiently large flow channel in the funnel flow hopper to avoid flow problems due to a rathole. The flow pattern in which a bulk solid discharges from a storage system strongly influences the flow problems that may occur in that facility.

Jan 1, 2009

By Meagan S. Boltz

From October 2000 to April 2001 a local array of fourteen seismograph stations was deployed at the Trail Mountain Mine (TMM), an underground coal mine in Emery County, Utah, to locate mining-induced seismicity (MIS). Original analysis of the data provided epicentral locations that coincided closely with the active longwall panel. The original analysis yielded poor quality hypocenters, however, preventing a useful relation from being made between mining activity and the event depths. For the original analysis, only stations at elevations above mine level were used for locating MIS. As a result, P- and S-arrival times from four of the stations in the local array were not used: an inmine station and three stations at elevations below mine level. This study compares mine workings and active mining to a revised TMM dataset that included P- and S-arrival times from the lower elevation stations that were not used in the previous study. In the revised locations, a modified master event methodology was used to calculate station delays. These station delays correct for errors in the shallow layers of the velocity model. The resulting hypocentral locations have improved depth resolution, determined by a lower root mean square (RMS) for the locations, compared to the original study. Most of the events occur in the roof of the mine and follow the longwall panel. When located using the velocity model determined in the original study, the elevations of the events increase as the longwall panel progresses. One possible explanation for the elevation increase is that it may be related to geology or the caving process. As presented here, a 10% decrease in the shallow velocity structure results in a more plausible location for the hypocenters. Consequently, it is hypothesized that progressive development of the TMM longwall panel(s) may have resulted in a progressive change in the velocity model.

Jan 1, 2012

By L. Adler

Longwall caving, one of the most economical and attractive mining methods, is yet one of the most difficult and hazardous.1 This dualism is inherent in a method which manipulates the mine supports themselves to aid in excavation. The difficulty is further compounded by the lack of an analytical method to predict and control results. This paper is intended to meet this need by providing a first approximation to the mechanics involved. The analysis will be limited to materials which are linear-elastic, homogeneous and isotropic. The rock structure is assumed to consist of beds of uniform thickness with no interbed bonding.2 Consequently, the mine roof can be likened to a beam, in which the action characteristic of longwall caving is the controlled deflection of the barrier supports. This deflection causes load to be intentionally transferred from these barrier props to the working face.3 Two of the requirements of this method, shared in common with other mining methods, are the provision of (1) adequate and (2) safe working space. The third requirement is the one characteristic of longwall caving and is somewhat in conflict with the second; (3) the development of near-failure static loads at the face. Requirement (1) is handled by spacing the barrier props sufficiently far from the working face for efficient operation. Requirement (2) limits the static stresses in the structure to predetermined allowable values. This means that it is not desirable to induce a maximum load on the working face as requirement (3) may imply. Such a condition could produce collapse in the whole structure. It is the purpose of the undercut to limit the depth, and thereby control the failure of the face. Therefore, requirement (3) really means the development of an optimum, not maximum, load which, in conjunction with undercutting, produces failure at the working face, with minimum powder consumption. Stress analysis requires an exact delineation of the structure and loads. The structure will be defined as the immediate roof and its supports. Since the roof is severed at the caving line, the supports reduce to the barrier props and the working face, as shown in Fig. 1. The mechanics of failure within the working face itself are complex and beyond the scope of this study, since the face represents a typical mine invert structure.4 However, this lack can be made good by the judicious collection of field data. The primary load on the structure is its own weight or body load which can be considered uniformly distributed over its upper surface. Additional loading occurs due to interference of overbeds with the structure. Wherever this occurs, the effect can be approximated by a load uniformly distributed on the upper surface of the structure.5 When this interference is intermittent, as with a much thicker overbed, the elastic curve for the overbed is superimposed on that for the structure and the extent of interference noted, as Fig. 2 shows. However, for simplicity, this study will ignore such intermittent loads without impairing the generality of approach. Consequently, the free-body diagram is that of a uniformly loaded cantilever beam with an inter-mediate support, as shown in Fig. 3. For convenience of analysis, the diagram will be divided just to the

Jan 1, 1961

By J. R. Heberger

"“Safety Pays in Mining” web application developed by the U.S. National Institute for Occupational Safety and Health Mining Program, helps mines determine the potential costs associated with mining injuries. This web app groups injuries by type, either by the cause of the injury or by the nature of the injury. When the user selects one of more than 30 common types of mining injuries, the app provides information on the distribution of costs of workers’ compensation claims for that type of injury. Based on other user inputs, the app will estimate the total costs of the selected injuries, including an estimate of additional indirect costs, the estimated impact of total injury costs on mining company profits, and provide some examples of other items, such as services or equipment, on which companies could spend the savings that result from the prevention of injuries. This paper reviews the app by discussing its development, how it is used to show the true costs of mining injuries, and how mines can benefit from using it.IntroductionInjuries on the job cause pain and suffering. They can also profoundly affect profits and daily operations. In addition to paying direct costs or increased premiums for workers’ compensation insurance, a company might need to pay overtime for other workers to fill an injured worker’s job role, cover training costs for a replacement worker or divert administrative resources in the wake of an injury. “Safety Pays in Mining” is a web app that estimates the distribution of these injury costs and assesses the impact that occupational injuries have on a company’s profits.The costs of specific types of occupational injuries in mining are not readily available as mining and insurance companies do not usually share this information. As a consequence, companies only have cost information based on previous experience with their own employees. Therefore, if a mine never experienced a finger amputation for one of its miners, for example, it would not be aware of the possible costs associated with this type of injury. In addition, injury costs are unique in that the cost distribution is so wide that just using the average cost of a specific injury type does not provide adequate information. Some injuries involve immensely high costs, and even though the risk of these high-cost injuries occurring is low, mines need to be aware of the potential impact on their company’s financial health."

Dec 1, 2018

By McHenry Mosier

This paper describing mining practice at Morenci, Ariz., is one of a series of articles on mining method, and practice in the various mining districts in the United States. At present (1929) practically all the mineral production in the Morenci district is from the Humboldt mine of the Morenci Branch, Phelps Dodge Corporation. The mining method used is adapted to the type of ore body being exploited; it has been developed by adopting methods used elsewhere and making necessary changes to fit local conditions. Improvements in current practices are still being made.

Jan 1, 1929

By Oliver Bowles

"Underground operation.In its broader sense the term ""mining"" is applied to all processes whereby raw materials are taken from the earth to be used as sources of mineral products. In a more restricted sense ""mining"" is applied to underground operations as contrasted with open pit work designated as quarrying. The tern is used in the restricted tense in this paper; for it relates to the exploitation of limestone deposits by modern methods of underground operation rather than by open pit methods.Present tendency toward miningIt may seem to some readers that a paper on mining limestone will find little general interest among lime plant operators, for only a limited number of them have yet resorted to this means of procuring raw materials. It is noteworthy, however, that a growing tendency exists toward underground operation, for one by one quarry owners are faced with increasing difficulties in open pit operation. It seems desirable, therefore, for operators to keep closely in touch with this gradual change in process, to inquire into the underlying causes, to compare costs, and to study the effects of the change in method on subsequent steps in calcining the stone to produce lime."

Mar 1, 1924

By Scott Ellenbecker

The formation in Newmont Mining?s Phoenix Mine near Battle Mountain, NV contains high levels of abrasive quartzite as well as gold, copper and silver. Newmont started mining operations at Phoenix (formerly Battle Mountain Gold) three years ago and the planners knew they were working with a challenging geological formation. But as it turned out, it was more challenging than anticipated. Mine manager Mark Evatz said, ?Anything that touches Phoenix rock wears fast. The rock fights back here.? To contend with the hard conditions, Newmont uses Atlas Copco?s Pit Viper 271 (PV-271) blasthole drill. Because of the hardness of the rock, drilling at Phoenix requires hammer drilling and the mine uses Atlas Copco TD65 hammers with 171 mm (6.75 in.) bits. The mine?s PV-271?s are outfitted with a single 41 m3/min (1450 cfm), 2.4 MPa (350 psi), oil-flooded air compressor. Phoenix has six Atlas Copco PV-271 drill rigs plus an Atlas Copco DML and a DM45 midrange blasthole rig. The mine?s goal is to keep 3.6 Mt (4 million st) of muck in inventory to stay ahead of the shovels and support needed operational flexibility (ore control related). Drilling efficiency has been a continuous point of improvement since operations began at the mine. The single-pass depth capability of 16.5 m (55 ft) on the PV-271 helped with that. Originally, the plans called for 6-m (20-ft) bench heights, supported by 7-m (23-ft) drill depths, and time spent moving from hole to hole was eating up productivity. Drilling on that plan resulted in drilling an average of 14 m/h (47 ft/hour). When depths were changed to 13-m (44-ft) drill depth, supporting blasting of 12-m (40-ft) benches, they were able to use the single pass capacity of the PV-271. Performance increased to more than 18 m/h (60-ft/hour) an hour. Although the drill depth change largely supported the improvement, other aspects of continuous improvement associated with improved knowledge of the Pit Viper drills helped as well.

Jan 1, 2009

By K. W. Lee, C. Pound, J. Carmody, L. Petersen, C. Nelson, J. G. Cai

The feasibility of developing the Underground Science City below the Kent Ridge Park has been investigated. The primary aim of the study has been to explore the possibility of creating underground space to house a new community of research laboratories and offices. The investigation represents the first such study undertaken in Singapore for a non-military underground facility. The paper describes the geology of the Underground Science City site and illustrates the layout and plan of the Underground Science City. The geology and rock mass below the Kent Ridge Park is generally favorable for the development of an underground cavern complex. Underground Science City can be potentially developed housed in a cavern complex. Several potential development schemes are studied; with various combination of deep/shallow mined caverns of different span sizes and access options. The preferred scheme is shallow, mined room-and-pillar caverns with large spans and shaft accesses at both existing surface Science Park 1 and Science Park 2. The scheme can be potentially expanded laterally to create more underground space for new Underground Science Cities at Kent Ridge area.

Jan 1, 2001

By Fred D. DeVanery

"INTRODUCTION Although galena is the most common lead-bearing mineral, is easily concentrated by gravity methods, and is readily susceptible to flotation, nevertheless some galena-bearing orebodies have within them small deposits of lead ore that fail to give a high recovery when treated by the customary milling methods.The secondary minerals, cerussite and anglesite, which result from natural oxidation of galena, cause losses when the customary method of lead-ore concentration is practiced. The identification of oxidized lead-ore minerals and the efficient concentration of a lead ore taken from the oxidized portion of an orebody which has previously yielded poor recoveries mere the objects of a recent investigation. Thus the ore examined was selected from a large orebody. The work was undertaken at the Mississippi Valley Experiment Station of the United States Bureau of Mines in cooperation with the Missouri School of Mines and Metallurgy, Rolla, Mo.DESCRIPTION OF OREThe ore was of a brownish color owing to oxidation of some of the iron minerals to limonite. The lead content was 6.80 percent, and a cursory examination showed that most of the lead was present as galena. Small amounts of sphalerite, siderite, and pyrite were readily identified. The chief gangue mineral was dolomite, accompanied by smaller amounts of calcite and glauconite."

Jun 1, 1933

By Zoë Mullard

Just as a mine has a lifecycle, employees working within the mining sector also make several transitions throughout their career, from initial recruitment to retirement from the industry. Throughout the employment lifecycle, employees bring skills and knowledge that significantly contribute to the global economy. These skills are developed through education, professional training, coaching and through hands-on experience. Despite the current economic conditions and the demand for minerals, the mining industry is facing a substantial skills shortage due to the disparity between the number of new workers entering the mining industry and a largely ?graying workforce?. Although educational programs continue to evolve to attract people with a wide range of skills, the diversity of jobs and the strains of working in remote mining operations continue to present challenges for recruitment and retention of employees. This gap also presents challenges around knowledge transfer at a corporate and mine-site level; employers will require cultural and techno-sociological approaches to ease through these transitions. At the same time, there has been an explosion of social media tools that facilitate information sharing, cross-organizational collaboration, distance learning and knowledge capture. These tools have become increasingly popular in the last few years and their applications vary widely. The mining sector has started to adopt these tools for a number of purposes, including opportunities to harness social media to enhance human resources interactions, outreach and oversight. This paper will outline several case studies that explore leading practices for how the application of new media can assist organizations and individuals as they progress through their careers. This paper will illustrate how new social media communication technologies can be used to increase employee engagement and build organizational capacity in the mining industry. The paper will also include strategies for how to implement social media to enhance human resources applications and will cover ideas for monitoring and evaluation.

Aug 1, 2013

By Scott G. Britton

Mine exploitation is a broad subject whose focus is the technical skills or efforts needed for the extraction of mineral from a known ore body. Mine exploitation can be considered the very core of the mining engineering discipline. It begins at the conclusion of the exploration and development stages of mining and ends when the ore body is exhausted and the mine (or mines)closes and is reclaimed. Section 8 on mine exploitation is comprised of seven chapters: (1) classification of mining methods, (2) mine surveying and mapping, 3) systems engineering, (4) computer methods, (5) labor relations and training, (6) management and administration, and (7) mine closure, sealing, and abandonment. Each chapter focuses its efforts towards providing detailed and useful information for the engineer on basic mine exploitation principles. The information can be applied to a broad range of mining problems without regard to mineral type or mining method.

Jan 1, 2008

By Rob Famlield, Gavin Yuill, William Birch

The Blasting Research Group at the University of Leeds, in the United Kingdom, continues to be highly active in the area of the environmental impact of blasting. In recent years a major part of this research has been concerned with the use of linear superposition. This technique relies upon the assumption that all the holes in a blast produce identical vibration signals. Previous work at the University has shown that this assumption is not sufficiently robust to be generally applicable. This is due to a number of factors of which the key variable appears to be dynamic confinement

Jan 1, 2002

By Huang Kai

By adding the solid oxalate acid powder into the solution of nickel chloride or its ammonia coordinated solution, the uniform compound particles were prepared and the precipitated particles were transferred to the mono-dispersed NiO particles by calcination. In this study, the various experimental conditions were investigated, the characteristics of the corresponding obtained particles were analyzed, and the formation mechanism of the particles was elucidated. It was found that the solid oxalate acid provided the solid-solution interface for the precipitation and induced the nucleation and growth of the product particles.

Jan 1, 2005