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By Alejandro Rosario, Ricardo González

The restrictions imposed by the Brazilian environmental legislation regarding natural caves lead to a block of substantial amount of mineral reserves. Mining activities can released caves, as long as the company ensures that the activities will not cause any damage to them, requiring profound and time-consuming studies. Since the use of explosives in the mine are potential sources of some damage to any structures, it leads to a deep need for controlling the rock blasting activities. In this context, the maximum charge per delay used in operations close to cave regions must follow some internal blasting assumptions that have been developed during specific tests and mining activities. By the seed wave technique, it is possible to determine the behavior of a seismic wave, which travels through a rock mass and it is generated by blasting a known explosive charge. This technique has proved to be an effective tool because it is able to accurately include the physical characteristics of the rock and different lithologies. This paper discusses about modelling blasting induced vibrations in order to improve caves protection, which surround the mining operations.

Jan 1, 2019

By I. Nishkov, L. Alexandrova

The kinetics of froth flotation and the three-phase contact (TPC) parameters are studied at temperatures varying from 20°C to 40°C. The material floated consists of glass spheres and a quartz particles with various diameters. Dodecylamine hydrocloride (DDAHCI) is used as a collector. The equilibrium three-phase contact angle is measured with a microscope technique using the modified Mingins-Scheludko method. Using a Wilhelmy method, the temperature effect on the surface tension of the DDAHCI solution is determined. The formation of the thin film on a polished plate of vitreous silica and the expansion of TPC is monitored by means of a metallographic microscope and recorded on a attached camera at different temperatures. The experimental data show an intensification of the flotation kinetics at 30 and 40°C in the case of small particles. Such an intensification is not observed with the larger particles. The cause for intensification of the flotation kinetics is sought for in the dependence of the TPC rate of expansion and induction time on temperature.

Jan 1, 1995

By Yuri L. Nikolaev

The treatment of placer gold with fine gold, associated with gold-bearing sulfide minerals, heavy minerals and oxidized minerals such as manganowolframite (gubnerite) is not an easy task. In this case, this complex material cannot be treated using physical separation methods such as deep concentration and finishing, magnetic separation and solvent extraction. This technology is usually employed in gold washings finishing plant. The easiest way to recover precious metals in the form of an easy-to-sample saleable product is metallurgical treatment. This paper describes the application of pyrometallurgical processes with oxidative roasting, re-cleaning of cinders (if required) and ore-thermal smelting for producing gold bullion. Hydrometallurgical treatment of slags as an additional operation is recommended in order to maximize recovery of valuable metals. After this treatment, a barren leaching cake rich in PGM can be sold in the market. PGM can be collected as gold-silver alloy during smelting which allows the phase formation of polymetallic matte due to specific composition of fluxes. The PGM are then in the form of saleable gold bullions in the refinery.

Sep 1, 2012

By J. Douglas Causey

In 1984, at the request of the Bureau of Land Management, the Bureau of Mines studied 9,600 acres of the 12,350-acre Antelope Creek Wilderness Study Area (MT-065-266) in order to evaluate its mineral resources. Within this report, these 9,600 acres are referred to as the study area. The Antelope Creek Wilderness Study Area, Phillips County, MT, adjoins the north end of the Charles M. Russell Wildlife Refuge. Considered part of the Missouri River Breaks, the area straddles the edge of a thrust fault zone that has deformed the Mesozoic strata in the west half of the area. Shale, siltstone, and sandstone of Cretaceous Age are exposed in the area. Coal beds averaging 3.0 ft thick occur in the Judith River Formation. About 0.20 million short tons of coal were mined from the Judith River Formation adjacent to the west boundary of the area; no production is known in the study area.

Jan 1, 1986

Develop an alternative to water bath exhaust conditioners (water scrubbers) for permissible diesel equipment used in gassy mines. Background Water scrubbers are a safety device used on diesel-powered vehicles in gassy mines. Exhaust from the engine passes through the scrubber, where it is cooled, and any flames or sparks present in the exhaust are extinguished. This prevents the ignition of combustible mine dust or methane that may be present. Unfortunately, water scrubbers consume large amounts of water and require frequent maintenance. Approach Methods that do not require water replenishment and frequent maintenance were investigated. The dry exhaust conditioning system was selected for investigation because no water is consumed and existing heat exchanger technology can be adapted to underground mine vehicles. In accordance with U.S. Mine Safety and Health Administration (MSHA) requirements, the system was designed to cool exhaust and trap flames and sparks. The U.S. Bureau of Mines (USBM) developed and evaluated a system for large engines and evaluated a second system for smaller engines. Both systems were evaluated on an engine test bed; if warranted, the system was then tested underground.

Jan 1, 1993

By K. N. Santini

Natural zeolites are gaining recognition as an important commodity with an increasing number of industrial and consumer applications. This potential has prompted the Anaconda Minerals Company and other firms to investigate occurrences and markets for zeolites. The deposits of mordenite-rich tuff at Rome are of interest for their economic potential and for the excellent opportunity they provide to study a zeolite deposit formed in a hydrologically closed basin. Location The Rome property is located approximately 9 km west of Rome, Oregon, in Townships 31S. and 32S., Range 41E., Malheur County. It lies within the Owyhee Uplands of the northern Basin and Range physiographic province (Figure 1). The area discussed here includes a major portion of the depositional basin in which the zeolitic tuffs occur.

Jan 1, 1982

By James Harding

THE usual method of sampling mineral deposits is to drill holes and assay the sludge or core. Though the results thus obtained may not represent the true average value of the deposit, it is on these results that estimates of practically all large orebodies are made. In a large number of cases, the results of exploitation fall far short of the estimated value of the orebody. The standard method of making these estimates is to find the cubic contents of triangular prisms, in the apexes of which the drill holes are placed, .by multiplying the surface area by the average depth of the ore in the three drill holes and then multiplying the cubic contents by the specific gravity of the ore or rock to find the tonnage. The assay value is found by dividing the sum of the products of the depth of ore in each hole and the corresponding assay value by the sum of the depths of the ore in the three holes. As the latter part of this method is subject to many mathematical errors, it should not be depended on.. Some engineers, therefore, use a discount factor, but as this factor is either arbitrarily selected or is obtained by obscure methods, the results are no better than guesswork. The standard method is correct when the drill holes are so laid out that the triangular prisms are equilateral in cross-section. But as ore deposits cannot always be drilled into at regular intervals and because of the human factor, if many holes are drilled, triangular prisms of all degrees of angularity are produced. In such cases, it is necessary to assume that the influence of the different holes is not the same in all directions, which assumption of course is absurd.

Jan 1, 1921

By W Medina, G Angulo, A Anani

A current challenge faced by the mining industry is solving the integrated transition mine problem (TMP) that maximizes the net present value (NPV). This study aims to develop an optimization framework capable of solving the TMP. The problem is NP-hard and therefore computationally intractable. Three ad hoc approaches – Exact solution, Benders’ decomposition, and Benders’ decomposition with Bienstock-Zuckerberg (BZ) algorithm – are compared for different scheduling periods. The TMP is formulated as a mixed integer linear programming model, implemented in Python, and solved with the Gurobi optimizer. The results showed that Bender's decomposition with the BZ algorithm outperforms the other approaches in execution time, computational cost, and feasibility to address large problems in exchange for a marginal cost in the quality of the NPV obtained. In addition, the probability of finding the optimal point of transition is higher regardless of the number of feasible crown pillar locations evaluated. This is achieved through the optimality cuts proposed in the algorithm.

Jun 25, 2023

By L. Nutter, J. Clancy

"Barite is used extensively by the oil and gas well-drilling industry as a weighting agent. It is particularly well suited for drilling mud because of its qualities; it is non-abrasive, heavy, virtually inert chemically, easy to handle and inexpensive compared to other available heavy materials. Increased deep well drilling in Western Canada, and especially in the Arctic regions, could dramatically affect the demand for barite through this decade. Known deposits in northeast British Columbia are possible sources of incremental barite supplies, should the situation develop.IntroductionThe purpose of this report is to examine the opportunities for expanding barite production in British Columbia. Of primary interest will be the relationship between the projected future levels of production and consumption of barite in Western Canada and the extent to which increased domestic production could replace the need for imports in filling any expected supply shortages.After a brief overview of the nature and uses of barite and some of the relevant features of the barite supply industry, the discussion will turn to the supply gap in the Canadian market and the possibilities for import substitution.OverviewBarite is an industrial mineral which is used in large quantities by the oil and gas well-drilling industry. It is often an important component of drilling mud, a fluid circulated continuously in the well during the drilling process to lubricate and cool the drilling apparatus and to contain the high oil and gas pressures found at depth. Barite (BaSO4) is particularly well suited as a weighting agent for drilling mud because it is a heavy (specific gravity to 4.5) inert mineral which is inexpensive in relation to other materials having a high specific gravity. In the on-site use of drilling mud, ground barite is combined with numerous other solid ingredients and chemicals in the form of a slurry. Other advantages of barite include cleanliness, ease in handling and its non-abrasive character (hardness of 3-3.5)."

Jan 1, 1982

By Les Johnston

_ BACKGROUND - About EPCOR - Genesee Generating Station - Phase 3 Expansion _ TECHNOLOGY SELECTION - Selection Criteria - Combustion Options - Flue Gas Emission Control Options _ STAKEHOLDER VIEWS _ PROJECT STATUS _ EPCOR is an integrated utility company for water, gas, electricity and technology services. _ EPCOR has about 1.6 million customers in Alberta, Ontario, Manitoba, BC, and the U.S. Pacific Northwest. _ EPCOR Generation Inc. operates three power stations in Alberta which were in operation before deregulation, including the coal-fired Genesee Generating Station. _ EPCOR Power Development Corporation owns generating stations in Alberta, BC and Washington State and will be building the Genesee Phase 3 expansion.

May 1, 2002

By H. E. Thomas

[The Bureau of Mines has conducted a field hydraulic fracturing experiment to determine the preferential orientation of induced fractures in oil shale at a depth of about 400 feet in the Green River Basin of Wyoming. The hydraulic fracturing treatment was performed by injecting extremely viscous water-base gel and 8- to 12-mesh sand into the oil shale through straddle packers set in an impermeable section of smooth-walled, 6-1/4-inch-diameter open hole. An impression packer proved that a horizontal fracture, which has an average width of about 1/2 inch at the borehole, was induced. A corehole drilled 100 feet from the fractured well intersected the fracture and confirmed its horizontal orientation. Because a horizontal fracture was successfully initi¬ated, it is inferred that the creation of multiple, closely spaced horizontal fractures may be feasible in Green River Basin oil shale.]

Jan 1, 1972

By Craig Ford

Inmet Mining is committed to implementing the highest corporate responsibility standards in its mining operations worldwide. Inmet is 100% owner of Minera Panama, a world-class copper project that is currently in the feasibility phase in north-central Panama. Panama has limited experience with modern mining, limited mining capacity, and the project context involves significant social, environmental and political complexity. The Project area is remote with recent in-migration of latino and indigenous people, informal and small-scale mining, local subsistence populations and considerable biodiversity value, coupled with a complex jurisdictional setting. In short, it is increasingly the kind of project mining companies are taking on because the easy projects have already been developed. With such challenging conditions, anticipating and managing social risks is critical to effective project management. To this end, between August 2007 and the third quarter of 2009 Inmet seconded Monkey Forest Consulting Ltd to the project to assist Minera Panama in building and implementing an effective, early phase external relations strategy. The team was also tasked to find and develop a locally based team that could sustain success through project development and into operations. Today?s presentation was created by Inmet and Monkey Forest and describes some of the lessons learned in implementing an effective early phase process for managing social issues.

May 1, 2010

By Luis Paretto Olivera

El objetivo del trabajo estriba en el desarrollo de un método práctico para la determinación del bióxido de nitrógeno a niveles de mayores niveles de concentración mayores, donde se utilize el reactivo de Saltzman especificado para el gas, elimine el problema de utilizar botellas o jeringas hipodérmicas, y se mejore los resultados productibles. El estudio fue complementado por comparaciones de concentración de bióxido de carbono determinadas con la jeringa hipodérmica y el burbujeador poroso y la relación de los mismos (técnica de muestreos, métodos de análisis,y estandarización).

Aug 20, 1963

By Long Han, A. V. Kalinin, Xiujian Luo, Xiaobo Wang, Xiaoou Xia

"Inertia vibration crusher is a kind of vibration equipment which crushes ore by vibration. When the inertia vibration crusher works, ore between the two moving jaws is subjected to the high frequency contact force, which is produced by the two moving jaws with high frequency synchronous reciprocating motion. The synchronous motion of the two moving jaws depends on the self-synchronous feature of the inertia vibration crusher. To study the self-synchronous feature of the equipment, the dynamic model was established, in which relative parameters were taken into consideration. The kinematic coupling relations of the assemblies are discussed, and appropriate calculation method is chosen to solve the vibrating differential equation. Whether the two vibration exciter can realize synchronous operation depends on the ability of the vibration system's capture moment. Results show that though the two rotors’ motors and damping coefficients are different, and two jaws’ damping and stiffness coefficients are also different, as angular velocities of the two unbalanced rotors reach a certain value, the vibrating system can be stable. Their angular velocities tend to be equal, and the swings of the two moving jaws can be the same. The horizontal vibration and swing of the frame are large in a few seconds after starting the machine. When the system runs stably, the horizontal vibration and swing vanish, and the vertical vibration is stable. The study and its results can provide reference for the optimization design and parameter setting of inertia vibration crusher and related vibratory equipments.INTRODUCTIONMaterials can be easily broken by using the inertia force of the vibration exciter, which can effectively realize the selective crushing, reducing excessive combinations and the energy consumption, as introduced by Zhang in 2005. The initial micro crack between crystals in the material increases and new cracks can be manufactured because of the high frequency impact and the extrusion of the vibration crusher, so vibration crushing equipment can make it possible for any high strength brittle material to be broken theoretically. Inertia cone crusher and inertia vibration crusher have been successfully used in the treatment of metallurgical slag and construction waste, and it verifies the efficiency of vibration crushing."

Jan 1, 2016

By Dan S. Nilsson

When an open pit mine is deepened, more and more waste rock must normally be removed. Techniques for optimization of open pit design are well-established within the mining industry. The recommended method is to choose the open pit alternative with the highest net present capital value of open pit and future underground mining. When the open pit is mined out, the operation must be closed, or, if it is profitable, mining must start underground. When planning an underground operation we experience the same type of optimization problem that occurs when determining the optimal depth for open pit mining. When mining underground the ore body is often divided into a number of areas, blocks or slices, each containing a transportation system with trains, trucks, conveyors, etc. When all the ore within such a part of the deposit is extracted, the operation must be closed, or, if it is profitable, a new transportation must be developed. The question that now arises is: how large a pan of a deposit shall be included in the first development and how much shall be left for future consideration?

Jan 1, 1981

By J. C. McCarthy, J. B. Stone

AT Fresnillo a series of veins that has yielded very large quantities of silver and other metals has been developed over a length of 6500 ft. and to a depth of over 3000 ft. In the course of this work striking changes in the mineralogy and metal content of the principal veins have been disclosed and are well illustrated by assay data and ore reserve calculations. This paper describes those changes and suggests their bearing on theories of ore deposition. LOCATION The Fresnillo mines and the adjacent city of Fresnillo are in the central part of the state of Zacatecas, 35 miles northwest of the capitol city of Zacatecas, once a great silver-mining center whose total production is said to place it fourth in the world. Another famous old silver district, Sombrerete, lies northwest of Fresnillo. Fresnillo is connected by a 5-mile branch with Fresnillo station on the Mexican National Railways line from Juarez to Mexico City. Lying near the southwestern edge of the central plateau of Mexico, Fresnillo ís surrounded by a semi-arid rolling plain from which rise widely scattered low hills. One of these is Proaño hill, an inconspicuous elevation rising barely 300 ft. above the plain, but in and around Proano hill are the Fresnillo mines, and it is marked now by a great gash cut by glory-hole mining. HISTORY According to an account written in 1834 by Francisco García, then Governor of the state of Zacatecas, Fresnillo was discovered in 1554, and a presidio was established there in 1568 to protect travelers on the road between Zacatecas and Sombrerete. Little is known of the earliest mining at Fresnillo, which seemingly began soon after its discovery, but by piecing together various accounts, it appears that mines there were working in 1717 and were notably active ín 1751 under an administrator named Murguía, who left detailed notes describing them. In 1757, however, the mines became inactive because of difficulties with creditors and no doubt also because of increasing water troubles, and they remained abandoned until 1830. In 1830 the mines at Fresníllo became the property of the State of Zacatecas because the interest of Governor García had been aroused by the long disregarded notes of Murguía. Under García's energetic leadership the mines were reopened, and silver production began in 1832 ín spite of serious difficulties, including abnormal rains and an epidemic of cholera. In 1835 English capital was sought to allow installation of steam-driven Cornish pumps at the two principal shafts and to build the great hacienda de beneficio (the present Proaño hacienda). The company formed in 11835 (Cia. Zacatecano Mexicana) operated successfully until 1872, when its career was brought to an end by the political and economic disturbances

Jan 1, 1942

By J Pan

This case study assesses the application of Mine-to-Mill optimisation combined with Whittle Consulting’s Prober<sup>®</sup> economic optimisation for the purpose of economic value uplift in open cut base and precious metal operations. The study extends the application of these optimisation methods to incorporate the recent practice of Ultra High Intensity Blasting (UHIB) developed by Orica Mining Services. The case study deposit known as “Marvin” is a copper/gold porphyry resource that is commonly used in optimisation software training and industry case studies. It has many similarities to Newcrest’s Cadia Hill open pit mine in NSW. Prior desktop research and industrial trials employed static assessments of Mine-to-Mill effects. No prior work other than a Whittle Consulting client study, has sought to assess the impact of variable fragmentation on enterprise economic value. This study examines the use of variable blasting intensity as a driver of economic value maximisation over the mine’s life.CITATION: Howe, S and Pan, J, 2018. Application of enterprise optimisation considering ultra high intensity blasting, in Proceedings Complex Orebodies Conference 2018, pp 14–20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By D. M. Urich

New plant construction for pyrolysis and agglomeration during 1969 has been relatively quiet in the North American scene. U.S. pellet capacity approximates 52 million long tons and that of Canada 25.3 million tons. The foreign scene, however, has been extremely active during 1969, and this is expected to continue for the next several years. Changes in sinter practice have not been reported, other than a few changes towards increased bed depths and the increased use of screening facilities to size the product more closely. Interest in the field of briquetting in fields other than iron ore is high with a new fluorspar briquetting plant under construction at Brownsville, Texas. Considerable research appears to be pointed towards solving the problem of reclaiming steelmill waste products (flue dust, BOF dust, mill scale) by means other than sintering.

Jan 1, 1970

By Carrie Pourvahidi

The California High Speed Rail Authority (Authority) was created by the State of California through legislation in 1996. The purpose of the Authority is to plan, construct, finance and operate a statewide intercity high speed passenger rail system. In 2004 the Authority prepared a programmatic level environmental document in compliance with the California Environmental Quality and National Environmental Protection Acts (CEQA and NEPA).The Authority and Federal Railroad Administration (FRA) were the lead agencies overseeing the development of the environmental documentation. The resulting document includes two volumes and 64 supplemental technical reports analyzing the transportation needs for California and the selection of an approach to meeting the project transportation needs. The Programmatic Environmental Impact Report and Environmental Impact Statement (EIR/EIS) identified High Speed Rail as the most environ-mentally protective, sustainable and economical approach to meeting the state?s projected transportation needs.

Jan 1, 2008

By John F. Vynne

This paper will discuss several of the systems and processes that have been developed over the past few years, and are now being utilized by major mining companies on draglines in North America, Australia and South Africa. These technologies include production monitors and reporting systems, GPS navigation systems, structural integrity monitoring systems, structural analysis studies to increase the dragline RSLs, and inspection and response strategies. The use of these technologies provides significant increases in dragline production, and reduces maintenance costs and downtime. The question that needs to be asked is what value is there in monitoring? Increasing dragline productivity is dependent upon to two items with the overall goal being to maximize the number of bank cubic meters moved and to uncover more coal: 1) maximizing payload and 2) maximizing the number of cycles. If you do not measure and try to optimize the parameters that impact payload and number of cycles, there is very little chance that you can improve overall dragline productivity. These parameters are: Maximizing payload is dependent upon the following: ? Geology ? Blasting ? Monitor weighing accuracy ? Engage location ? Disengage Location ? Rigging ? Suspended load ? Bucket characteristics ? Operator skills ? Minimizing rehandle Maximizing the number of cycles depends upon maximizing digging time, and minimizing cycle and delay/down times by: ? Minimizing Operational Delays ? Minimizing Mechanical Delays ? Minimizing Idle time ? Minimizing Walking time ? Minimizing Fill Time ? Minimizing Swing Angle ? Maximizing Swing & Return Rates ? Minimizing Spot Time A third reason to monitor, conduct structural analysis studies, and have inspection strategies is to prevent catastrophic failures such as shown in the following photographs (figures 1 & 2).

May 1, 2008