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By Harold J. Schock

The cases of no auxiliary ventilation and ventilation with tubing were mathematically modeled, using a turbulent dispersion model. The scooptram that is used to load is modeled as a variable-speed, variable-strength source of pollutants moving in and out of the dead-ended drift. Model predictions are compared to experimental measurements. A parametric analysis was performed to determine the effect of exhaust pipe location and time spent out of the drift, as well as to determine if a relationship existed between CO2 and NO levels. It was concluded from this analysis that when modeling a load-haul-dump cycle, it is necessary to use a model that has the capability of predicting changes in source strength as well as source location. It was also determined that four relevant factors include effective heading height, apparent longitudinal diffusion coefficient, transverse concentration gradient at the face, and average dispersion width of the exhaust jet. As these factors change with heading geometry and ventilation configuration, they were determined experimentally, Carbon dioxide was used as a tracer to calibrate the model; since, knowing the fuel flow rate, it is possible to calculate CO2 production. The above four factors in the computer model were calculated using a regression analysis, comparing predicted local concentrations to measured local concentrations. The model was then verified after this calibration process using additional experimental results. With the calibrated model, it is possible to predict pollutant concentrations at any location in the heading using an engine map and the previously calculated flow field. A parametric analysis shows that the exhaust pipe location can have a significant impact on operator exposure to exhaust gases. It was also shown that NO concentration varies directly with C02 levels. Predictions using the dynamic model are contrasted with constant source strength (pollutant flow rate) results. An analysis of these predictions for computing time-weighted average NO shows the dynamic model predictions of operator exposure to this pollutant to be less than one-half of the value predicted using a constant source model.

Jan 1, 1981

By D. D. Potter

ABSTRACT OF ORAL PRESENTATION Extraordinary conditions are often encountered when designing large blasts for in situ mining methods and spatial or innovation techniques are sometimes required. Some of the considerations in designing these large blasts will be discussed with emphasis on those factors that concern powder factor, rock movement and fragmentation. Sources of basic data will be described, along with some of the methods for obtaining these data.

Jan 1, 1977

By Bob Snashall

Introduction 1300 BC, Egypt. Pharaoh, the god-king, owned all things. He was the only mine operator. As the provider of all things, Pharaoh had great expectations of his officials who gathered the wealth. Pharaoh's official, the mine foreman, was at a gold mine site to see that royal expectations were met. For the official, it could mean a promotion to the good life here and to the godly life hereafter. When he checked the haul for sufficient progress, a lot was at stake. The miner wore a loincloth, perhaps a headband and, if he was a prisoner, ankle manacles. Only an oil lamp helped illuminate the hot, dusty blackness. A fire at the base of the quartz ore face competed for scarce air. The ore so heated crumbled at the prompting of copper wedges. Confined to a crouch, the miner tossed chunks of ore onto a rope-mesh which, when loaded, was drawn up and lugged out. On the surface, the gold was ground to dust. Then it was transported by donkey caravan to the royal depot. There it was weighed, recorded, and distributed to workshops. Many minerals mined Egypt had gold mines to the south in Nubia and to the east in the desert and Sinai. Indeed, gold underwrote Egypt's prosperity. With a constant gold supply, fewer hungry hands robbed burial crypts and tombs. Gold was sacred, "the flesh of the gods." The shiny metal financed the army that policed the desert mining routes and guarded the gold caravans from Bedouin marauders. Gold theft was an offense to the gods. Anyone caught with gold `in his lunchpail,' so to speak, could say goodbye to life, both in this world and the next. In addition to gold, Egypt possessed other mined riches that allowed the Egyptian civilization to flourish. From Sinai and Nubia came copper. So abundant was the red metal that it enabled Egypt to become the supreme power, before the advent of iron. Also mined were amethyst, turquoise, feldspar, jasper, carnelian, and garnet. These were used for the rich inlay work that distinguished Egyptian jewelry and cloisonne. But Egypt's most endurable and awesome material was its stonework - for statues and obelisks and in temples, tombs, and pyramids. Stone quarrying was a vast enterprise. One expedition boasted nearly 10,000 men. These included 5000 laborer soldiers, 130 skilled quarrymen and stonecutters, and - egads! - even 20 scribes. In addition, there were thousands of officials, priests, and officers grooms. There were even fishermen, to provide the multitudes with the catch of the day. Mining methods detailed In 1300 BC, quarrying techniques had changed little since the age of the pyramids some 1300 years before. At that time, in 2600 BC, limestone was locally quarried and fashioned into the blocks of the pyramids. A basic limestone mining method was tunnel quarrying. A ramp was built up to the face of a cliff. A monkey stage was then erected on a ramp. While standing on the stage, quarrymen carved out a rectangular niche in the cliff. The niche was large enough for a quarryman to crawl into. With a wooden mallet, he hammered long copper chisels along the edges of the niche floor to free up the back and sides of the block. The quarryman climbed out of the niche and removed the stage. He then carved out a series of holes in the cliff face for what would be the bottom of the block. The quarryman pounded wooden wedges into the holes. He watered the wedges until they were soaked. The water-logged wedges expanded, splitting the stone along the line of holes. The freed-up block was then levered down from the cliff. On the ground, the blocks were placed on sledges. Men pulled these to nearby water transport. Without block and tackle pulleys, paved roads, and wheels, this was no mean feat. Each block weighed an average of 2.3 t (2.5 st). Whenever possible, the quarrying was done directly from the surface. This "open cast" quarrying also involved using chisels

Jan 2, 1987

By Kevin B. Doyle

Virtually all industries use sulphur in some form. About half of the world's production is used in the production of fertilizers. Sulphur is produced in one form or another in over sixty countries in the world. The major producing countries, in order of importance, are: U.S.A., Canada, U.S.S.R., Poland, Japan, France, Mexico, and Spain. Canada is the largest exporter of sulphur presently supplying about 30% of the world elemental sulphur export trade. It has held this position since 1968. World sulphur resources are virtually unlimited. Future world competition will come from Iraq and other Middle East countries as well as Central and South America.

Jan 1, 1978

By A. Fleming

The exploration process, like any other commercial activity, can only succeed if the objective of the exercise is clearly defined and persistently pursued. Successful exploration requires properties, funding, personnel and persistence. Many of us have years of experience in conducting exploration in our countries of residence. Conducting exploration in a foreign country, however, requires a number of significant other criteria.

Jan 1, 1997

By C. Villa Diniz

It is proposed that battery grade Mn02 can be produced directly from a manganese ore from Azul Mine in Brazil, by leaching with HCI to remove heavy metals selectively. We are working to find a way of selectively separating Cu, Ni, Co, Pb and Fe from the resulting acidic manganese chloride solution, to detoxify it and produce marketable chloride solution. Chelating ion exchange resins are proving more promising for this separation than solvent extraction with commercially available reagents. Results from batch and column ion exchange tests that characterize the behavior of copper, nickel, cobalt, lead and iron are reported.

Jan 1, 1999

By Roberto L. Romero

The dressing of Bolivian tin ores has been done up to the present by classical. gravity methods, taking advantage of the high specific gravity of cassiterite compared with that of the accompanying gangue. For this purpose, jigs and shaking tables are used in the treatment of the various size fractions in which the ore is classified. Bolivian ores are mainly of the vein type and, to obtain a reasonable separation, crushing and several stages of grinding are necessary during the process to substantially liberate the cassiterite from the gangue. Gravity processes for cassiterite are effective for sizes down to 200 mesh. Below this size the efficiency of the gravity methods falls off very rapidly with increasing fineness of the mineral grains. The conventional treatment for this material is desliming followed by tabling on shaking tables various other types of machines have been designed for the gravity treatment of these fine particles but they have had limited success. Bolivian ores contain an appreciable amount of minus 200 mesh material constituted by "primary fines" caning from the mine itself, and "secondary fines" originated during the crushing and grinding necessary for liberation of the difficulty in the treatment of these fine particles is one of the causes why the recovery of tin in concentrates is only of around 50% in the mines owned by Corporacidn Minera de Bolivia, the State owned enterprise. The average figure for other Bolivian mines is

Jan 1, 1971

By M. M. Veras, C. H. Sampaio, A. S. Young, D. Neto, C. O. Petter

"Due to new technological developments, automatic sensor based sorting has made progress within industrial minerals, precious metals, diamond, and coal mining in recent years (Lessard et. al. 2016). In order to re-introduce the technology to other mining sectors, this research discusses its application to iron, manganese, and zinc ores through test works performed by the authors. These test works were performed using Dual Energy X-ray Transmission (DE-XRT) sensor technology. In each case, pre-concentrations of the ore were created demonstrating the possibility to reduce waste material, energy costs, and water consumption while improving product quality of the ores. INTRODUCTION Sorting of mining ores is as old as mining itself (Salter, 1991). Sensor based sorting applications in coal mining began as early as the late 19th century (Louis 1928). New sensor technologies were developed and implemented sequentially for uranium, nickel, coal, and gold mining (Refining, 1949, Rose et al, 1950, Bloomfield et al, 1966, Clayton et al, 1987, Robben and Mosser, 2014). While these sensor technologies were developed decades ago, computational capacity to keep pace with the vast amount of information required utilizing the sensor technology did not arrive until recently (Lessard et. al., 2016). The sensor based sorting (SBS) process was effectively described by Salter and Wyatt in Minerals Engineering in 1991, and Wotruba and Harbeck in 2010 in the Ullmann’s Encyclopedia of Industrial Chemistry under Sensor Based Sorting. Both descriptions include the following key steps: 1. Presentation of the material or particles. 2. Examination or detection of the material or particles. 3. Processing or analysis of the data generated. 4. Physical separation of the material or particles by external means. Effective presentation of the material or particles is achieved when the sensor is capable of identifying each particle individually. This step requires that each fragment of the material be isolated, and it often involves acceleration of the material fragments by chute or mechanical means, as well as the spreading of particles by vibratory feeders (Salter and Wyatt, 1991, and Wotruba and Harbeck, 2010). The isolated particles typically are conveyed into an area wherein they are subjected to electromagnetic irradiation (except in cases of some radioactive ores), either in the form of x-ray, visible light, infrared, or other energies. A wide range of applications for sensor based sorting exists in the literature. The majority of applications fall into one of two camps, (1) pre-concentration of mineral ores, or (2) characterization of the material during processing (Buxton and Benndorf 2013). While there is much to be gained from in-line material characterization and the resulting control both of quality and processing, this article focuses primarily on the camp of pre-concentration of mineral ores."

Jan 1, 2017

By HASAN SERKAN GOKCEN, SERKAN CAYIRLI

The purpose of this study was to investigate the dry grindability of calcite powders in a vertically and horizontally orientable laboratory batch type stirred mill. The experimental results were evaluated using stress intensity analysis. The performance was also compared in terms of mill orientation. The results showed that the d50 values decreased with increasing stress energy down to a certain point and then increased for both milling orientations. Even though the optimum stress energies for both vertical and horizontal orientations were in the range of 1*10−3 to 5*10−3 Nm at 750 and 1500 kJ/kg energy consumption, the product size was finer for the horizontal orientation at the same stress energy value. Additionally, to the best of the authors’ knowledge, this is the first study to compare mill orientation (vertical vs. horizontal) for the same mill and under the same test conditions.

Apr 21, 2021

By D. J. Beeby

California's Surface Mining and Reclamation Act (SMARA) was passed in 1975 to identify and protect mineral resources in areas of high land use conflict and ensure reclamation of mined lands. Under SMARA, aggregate resource availability is quantified and compared to forecasted demand in specific market regions. Fifteen regions studied thus far cover 51,800 km2 (20,000 sq miles) and contain 45 Gt (50 billion st) of high-quality aggregate resources that have been legally designated as "regionally significant," providing a measure of protection previously unavailable. SMARA reports and state testimony at local hearings have supplied objective information and helped reduce conflict in mine permitting decisions.

Jan 1, 1987

By R. W. Smith, D. Clare

The removal of metals from an acid mine drainage (Leviathan Mine, Alpine County, California) water by precipitate flotation was investigated. The Leviathan waters vary from about pH 4.0 to pH <2.0and contain from about 2,000 to about 12,000 ppm SO42-.The main multivalent metals present in solution are Fe, Ca, Mg, Al and Mn. Both Cu and Co are present in small amounts. The pH was adjusted with lime. The collector used was either sodium oleate or tall oil. The sodium oleate was used as a function of pH to establish optimum flotation conditions and the tall oil was used only at the optimum pH. Dow Froth 250 was used as a frother. In some test additional Cu was added to the system. Excellent recovery of Fe and Cu were achieved at optimum pH. The process achieves results comparable to precipitation and filtration without as much problems with screens blinding because of less material to filter.

Jan 1, 2004

By N. S. Tanious

This work was completed prior to the author&apos;s appointment with the Nuclear Regulatory Commission (NRC). Therefore the views and conclusions contained in this paper are those of the author and should not be interpreted as necessarily representing the official policies or recommendations of the NRC. Reference to specific brands, instruments, or trade names is made to facilitate understanding and does not imply endorsement by the author or the NRC.

Jan 1, 1987

By Garry M. Hughes

Lynn lake, Manitoha, where Sherritt has operated a copper-nickel mine since 1954, is located north of the 56th parallel approximately SOO miles north of Winnipeg. Sherritt&apos;s new, 3,000 tpd, copper-zinc Fox Mine is situated 30 miles southwest of Lynn lake. This paper focuses on the Fox Mine concentrator, hut first some background information. Sherritt Gordon Mines Limited started mining operations as a copper-zinc producer in 1931 at Sherridon, Manitoba, 150 miles south of Lynn Lake. As Sherridon fizzled out development of a series of nickel-copper orebodies commenced at Lynn Lake. The Forward process was developed to treat the nickel concentrate from the Lynn concentrator. Sherritt&apos;s ammonia leaching process is now history and is expected to gain more prominence as pressure is applied to the mining industry for closer environmental control. But few are aware of the fact that the present Lynn Lake crushing plant and concentrator were dismantled in the autumn of 1951 and freighted from Sherridon by tractor train during the winters of 1952 and 1953. The copper-zinc orehody at Fox Mine was discovered early in 1961 by geophysical methods which included both airborne and ground surveys. It is part of a ,large body of massive and semi-massive sulphides consisting chiefly of pyrite; with chalcopyrite, sphalerite (containing 7-9% iron) and pyrrhotite in varying proportions which occur within a series of volcanic and sedimentary rocks. The total mineralized zone is a lenticular body with a minimum average length and width of 1,350 feet and 66 feet respectively, to the explored depth of 2,000 feet. The average sulphide content is 67%. Higher zinc zones are masses of pyrite grains cemented by sphalerite with lower than average copper content. Zones higher in copper and lower in zinc are slightly more quartzose. Gold and silver are present in small amounts roughly proportional to the copper content.

Jan 1, 1971

By Ari Glazer

"Every year the tunneling business is expanding and collaboration with the International Society of City and Regional Planners (ISOCARP) for the future design of cities and urban communities is in the making. During the last half of this century, billions of people migrated to cities, and it is estimated that by 2030 almost five billion people worldwide will reside in urban communities. Hence, “Underground development will be an important tool in reshaping our urban areas to meet the challenges of the future without destroying their heritage or worsening their surface environment” (Esaki, 2005). In 2013, the Organization for Economic Co-operation and Development (OECD) estimated life expectancy to be around 80 years, meaning that in less than a decade we will need to bury billions of people in cities and urban communities, while trying to retain the deceased’s beliefs and customs. Religion plays a major role in our lives, and many people worldwide still decline to cremate their body after their death; therefore, cemeteries are essential for city inhabitants. Rites and traditions usually call for burials to be near the place of residence, which allows the remaining family members and friends to visit the grave frequently, at least in the first years. This is a challenge that urban designers and architects must confront while trying to solve the problems of future urbanization. In recent years, population growth, the rising cost of land and the extensive preservation of green areas have made cemeteries a burden and a nuisance, particularly for large cities and communities. Many graveyards that were once on the city's outskirts have become lifeless islands in populated areas (Fig. 1), rarely visited by the second and later generations. Cities worldwide face the challenge of allocating less land to maintain current burial practices. In response, some cities have begun to bury their dead at a great distance from the community; others have started to stacked burials, one on top of the other, while still others are constructing buildings and even skyscrapers for the practice of burial (Fig. 2)."

Jan 1, 2016

By J. F. T. Agapito

Significant economic benefits can result when rock mechanics is applied within a practical framework and integrated within the other engineering functions of the mine organization. This requires management support and understanding of rock mechanics as a practical tool to help attain high standards of safety, productivity and resource recovery. For such an approach, a long-term geotechnical program is needed in most operations to build an adequate data base and to ensure that design and ground control issues are handled in a cost-effective manner. This paper presents a summary of four case studies where significant economic benefits were realized with the help of rock mechanics. Although cost savings were not computed, the economic benefits are obvious and clearly impacted the mine operations favorably.

Jan 1, 1990

By D. W. Mitchell

Planning today for what hopefully will never happen is one of the surest ways to decrease the chance of it happening. As Napoleon proved and Ian Mitroff wrote, "The heat and stress of battle is the worst time to make decisions of strategic importance." Mitroff also wrote, "The value of a plan is not that it will ever perfectly match reality, but going through the process of planning speeds the process of recovery. It allows the organization to emotionally work through the worst before it actually happens." This paper concentrates on things miners must consider; on the need for plans to be like a belt conveyor strong enough to carry the load, flexible enough to stretch a little; on the criticality of throwing away fax machines and telephones, and having certain officials at the scene rather than back in head-quarters; on the training of fire brigades and mine-rescue teams; on having company-controlled chromatographs; on having people who can look at trends rather than numbers. Some of the things in this paper might anger some readers; for that, I can only ask them to consider first the problem not their position.

Jan 1, 1993

By John L. Watson

The processes of magnetic separation and cyclone classification are common in the mineral processing industry, and frequently the two are found in consecutive stages in the beneficiation of a magnetic mineral ore. The application of a magnetic field across the cyclone, to combine the two stages in treating a magnetic mineral pulp, has been investigated with a view to possible practical applications in the mineral industry The results of this research reveal that magnetic particles can be manipulated within the cyclone body by the application of a magnetic field, and that magnetic grades may be significantly upgraded with recoveries in excess of 90%.

Jan 1, 1983

By Verya Nasri, Jaeseoung Lee, Ashish Bhargava, Shashank Gupta

This paper presents the unique design and construction challenges for the Technoparc Station, located in downtown Montreal as a part of Réseau Express Métropolitain (REM), a light rail rapid transit system. The station is located 15 m below the street with rock-bearing secant pile wall as the primary structural system working as both the retaining and gravity structure. The paper highlights the challenges related to the support of excavation structure, invert slab resisting high hydrostatic forces, waterproofing tightness etc. It also focuses on the importance of Building Information Modeling (BIM) in underground tunneling projects for effective coordination, clash-free, optimized design and costs.

Jun 13, 2021

By H. Sevim

An innovative approach in designing the haulage systems for underground coal mines is discussed in this paper. The haulage systems are formed by serially connected components. Therefore an economic and efficient design of the entire system is necessary. The computer model that uses a heuristic algorithm solves this design problem globally in a single run. It is a probabilistic model because it considers the probabilistic aspects of face operations. It is versatile because it can accommodate any type of mining and belt conveyor network configuration. The hoisting section can be used to design drum or friction hoisting systems for single or multiple level operations. These systems can have two skips in balance or a skip and a counterweight in balance. The model also has the option to internally determine the capacity of bunker(s) and shaft-bottom bin. The objective is to minimize the expected cost per ton of coal hauled from the coal faces to the surface. At the end of the paper is an example that illustrated the capabilities of the model.

Jan 1, 1987

By Richard Cole

The Energy Act of 1992 has many users of ac-induction motors eyeing premium-efficiency motors with mixed feelings and perhaps some confusion. When the October 1997deadline arrives for compliance with the1992 standards, the winners will be the environment due to reduced need for more power generating plants and the petroleum economy because of reduced dependency on foreign oil. But what will it mean for industrial users? The most obvious benefit is the potential for smaller electricity bills. Motors account for about 64% of the electricity consumed in the United States, at a yearly cost of $112 billion. Every 1% reduction in motor demand cuts 0.64%, or $716 million, off the industry wide bill. Higher efficiency motors also run cooler. This lightens the load on air-conditioning systems and further reduces plant demand. Lower total demand can lead to lower rates by helping to minimize peak-demand surcharges. As rates increase over time, these savings get bigger.

Jan 1, 1996