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By Jr. Moulton

Extractions of minerals from Searles Lake brines have taken place since 1873. Early operations were for borax and raw trona found on the surface, expanded after 1914 to include potash, salt cake, and soda ash. A new soda ash plant now in operation will double area production. The evaporite beds were formed by desiccation of Eastern Sierra runoff. The resulting series of brine-bearing salt beds supply the fluids necessary to feed the area chemical plants. Production methods include evaporation and crystallization for potash, borax, and salt cake; carbonation of brine to recover soda ash; and organic extraction of borax.

Jan 1, 1980

By Donald P. Moore

During April 1967 a Frasch sulfur mine was placed in operation near Fort Stockton, Pecos County, in West Texas. This was the first Frasch mine to recover native sulfur from a deposit not associated with the caprock of a salt dome. Since 1967 two additional mines have been opened in west Texas, another one near the first at Fort Stockton and a third one near Orla in Culberson County (Figure 2). Recoverable reserves at the Culberson County mine are estimated to be 57,000,000 long tons of native sulfur (Zimmerman and Thomas, 1969). Total recoverable reserves at the three mines probably exceed 60,000,000 long tons, Studies of the geochemical cycle of native sulfur mineralization in test Texas indicate an origin similar to the deposits on salt domes although the geologic framework is different. A comparison of the geologic setting of the west Texas deposits with the deposits in the Union of Soviet Socialist Republics as reported in the literature, reveals many similarities. ACKNOWLEDGEMENTS The writer wishes to express his appreciation to Cities Service Minerals Corporation for support throughout this study. Special thanks are due Dr. Chris Riecken and Mr. Dave Hardy for their

Jan 1, 1971

By N. K. Dumakor-Dupey, G. B. Sakyi-Addo, K. J. Bansah

"Artisanal and small-scale mining (ASM) occurs in many countries around the world, and provides a source of livelihood to many impoverished local people in areas where it occurs. This paper reports the role of female participants and reasons why they engage in ASM. Field visits were made to 12 ASM sites located in the Tarkwa Mining District of Ghana to conduct interviews with male diggers and female participants. It was observed that over 100 women between the ages of 18 and 50 participate in ASM for survival. They engage in ASM largely because they have no alternative employable skills and income sources. These female participants depend on ASM to sustain the lives of their dependents. INTRODUCTION Artisanal and small-scale mining (ASM) conventionally involves use of rudimentary tools (such as picks, shovels, chisels and hammers) to exploit precious minerals and metals from the ground. It has been a major source of livelihood to many impoverished local people for more than a century. In many instances, it is the only source of income to indigenous people who have no alternative employable skills. The World Bank estimated that more than 100 million people around the world benefit from ASM which largely occurs in developing countries in Asia, Africa, Oceania, and South and Central America (World Bank, 2013). Cobalt, which is used in lithium-ion batteries to power cellphones, laptop computers, and electric vehicles, is largely produced by artisanal miners in Congo (The Washington Post, 2016). In Sudan, ASM is a significant contributor to the national economy, accounting for about 85% of total gold extracted yearly from 2010 to 2015 (Ibrahim, 2015). Also, according to the Embassy of Sierra Leone in Washington DC, USA, 90% of mineral export in Sierra Leone can be attributed to thriving artisanal diamond mining in the country (Sierra Leone Embassy, 2016). In Ghana, the ASM sector was recognized by government as a multimillion industrial activity, and through a series of initiatives, it was legalized by promulgating the Small Scale Gold Mining Law of 1989 (PNDCL 218). Presently, artisanal mining is widely practiced in two forms: licensed (registered), sometimes referred to as formal ASM, and unregistered (informal or illegal) operations, popularly called “galamsey”, a name believed to have been derived from “gather and sell” by ancient miners who could not communicate in the English language with European/British miners. The ASM sector in Ghana, like other countries, has seen a rise in female participation over the years. A report by the International Labour Organization (ILO) indicated that women account for about 15% of total workforce in ASM in Ghana, and up to 50% in Africa (ILO, 1999). Other researchers have also estimated women participants in ASM to be between 30 and 70% in Africa (Hinton et al., 2003a; Hinton et al. 2003b; Hilson, 2002). Presently, there is no reliable data from Ghanaian authorities on number of females engaged in ASM. However, data obtained from 15 ASM sites suggest that at least 40% of the employees are women. It is expected that a similar trend exists across ASM operations in Ghana."

Jan 1, 2017

By LeRoy Kienitz

There may be someone here who is not required to run his equipment at its maximum capacity. There may be some fortunate enough to have more crushers than needed, wider conveyor belts than required, and other mill equipment equally oversize. If so, then this paper will have no interest for him; but if most of you are in the situation we in the aggregate producing industry are in, then you probably wish to crowd your mill equipment to its limit. When you do this you must watch for block-up and overloads of all sorts. You need more eyes than you have to guard the critical points. The human eyes that now do nothing much, but watch should be freed for more productive work.

Jan 1, 1961

By Robin J. Batterham, Dave J. Robinson

The history of mineral processing in general and flotation in particular is long and has always been tied to mining methods of the day. Building on the ever-improving fundamental understanding of the underlying science, the most significant trend in flotation has been the putting into practice the learnings from trailblazers such as Professor Fuerstenau that has given the confidence that enabled an ever-increasing scale of operations. There is, however, doubt this ongoing trend is enough to maintain the economics against global trends such as that of falling grades, increasing mining costs, pressure on water supply and demand, rising energy demands needed for mineral processing, and a focus on whole of life value and mine legacy issues. In addition, we see that globally, the social license to operate for mining (and hence mineral processing) is far from secure and, at the very least, is under much more rigorous scrutiny. In this paper, we comment on the ramifications of broader uptake of more sustainable mining for mineral processing methods and address the specific question of whether recent progress in in-place recovery will lead to a timely breakthrough. The answer proposed is that this is possible in the next 10–20 years but in the meantime, the focus is just as likely to be on removal of waste (beneficiation) much earlier in circuits. Either way, mineral processing and flotation, as we know it, will change significantly.

By C. I. Huang

The mining industry is an easy target for criticism from an environmentally sensitive society. Recent researches discovered that human activities, including mining. cannot be blamed for all of the pollution observed on earth. Interdisciplinary research is providing diagnostic and remedial solutions to problems such as acid mine drainage and cyanide-polluted streams. Researchers have also found that mercury-bearing hot springs and volcanic eruptions are partly responsible for some pollution. Geochemists, mining geologists, engineers, and environmental scientists can pool their efforts to make the environment cleaner and safer. Remote sensing of the environment and the use of microbes may become much more popular in the near future in the mining-environment arena.

Jan 1, 1988

The mineral sands industry is oriented primarily toward the supply of titanium (Ti) raw materials (titanium feedstocks) for the production of titanium dioxide (TiO2) pigment and titanium metal. Titanium minerals ilmenite, rutile and leucoxene, and titanium slag and synthetic rutile are all used principally as feedstocks for the production of white TiO2 pigment. It accounts for almost 90 percent of the world?s consumption of titanium minerals. The remainder is used for the production of titanium metal, fluxes for welding rods and as a metallurgical flux in iron and steel making. Titanium dioxide pigment is produced by two alternative process routes, the sulfate process or chloride process. The bulk of the world?s titanium dioxide is derived from the mineral ilmenite, which also contains iron oxide and other minor impurities. At some mining operations, the iron present in ilmenite is removed (ilmenite beneficiation) to produce a high TiO2 feedstock (slag or synthetic rutile) typically containing between 80 percent and 95 percent TiO2. Pigment producers then further process it to produce pigment.

Jan 1, 2011

By Priscilla P. Nelson

Many concepts concerning equipment selection, performance prediction, and evaluation of support requirements for tunnel construction in soil or hard rock tunnels cannot be extrapolated directly for application in soft rock (compressive strength between 1.0 and 35.0 MPa). Case histories for small diameter (less than 3.5 m) tunnels in Austin, Texas, are analyzed to gain insight into particular problems encountered during tunnel excavation in weak sedimentary rock, and the performance of different excavation systems are compared.

Jan 1, 1987

By Micheal Mitariten

The recovery of natural gas (primarily methane) from coalbed deposits is an established and growing source for the U.S and accounts for over 7% of its total production. The gas from on-purpose degassing is often pipeline quality and requires only compression and dehydration before being admitted to the pipeline grid. However, the raw gas is sometimes contaminated with nitrogen (N2) and/or carbon dioxide (CO2) that can make the gas inadmissible to the transportation pipeline. In general, the N2 must be 4% or less and the CO2 should be 2% or less. In treating gas produced from virgin coal bed or from degassing operations where CO2 is present, amine systems are traditionally used for its removal. Engelhard’s Molecular Gate® adsorption system offers an attractive alternative due to its skid-mounted equipment, low pressure and unattended operation, cost and high on-stream reliability. Natural gas can also be sourced from the residual coal, after the coal has been mined. This source can be the GOB or gas remaining in abandoned coal mines. This source is almost universally contaminated, often with a combination of CO2 and N2. If the source is from air intrusion, the source can also be contaminated with O2. In treating CO2 / N2 contaminated feeds, the Molecular Gate adsorption system removes both of the impurities along with a level of O2 within a single processing step. To date, ten Molecular Gate units are underway with three systems having been installed for upgrading gas from abandoned coal mines. The technology consists of specialty adsorbents and advanced PSA processes that are jointly offered as fabricated packaged equipment by Engelhard Corporation and Guild Associates, Inc. Upgrading requirements, project challenges and project arrangements are discussed in this paper.

Jan 1, 2005

By T. D. Rourke, E. J. Cording, O&apos

INTRODUCTION Detailed investigation of a 60-ft-deep excavation in a mixed profile of sands and stiff clay was performed by the University of Illinois for the Washington Metropolitan Area Transit Authority (METRO). The work was coordinated through DeLeuw, Cather and Co., the General Engineering Consultant of METRO. Instrumentation was concentrated in a portion of braced excavation for the Gallery Place Station near the intersection of 7th and G Street. The early construction date, the 60 ft depth of cut, and the proximity of large buildings formed the basis for selection of this site as the focal point of observation and measurement. A history of lateral and vertical displacement is provided wherein movements which occurred during excavation to the full depth of cut and, subsequently, during station construction and the removal of braces are described in detail. Observations of preloading and the consequent brace loads and wall displacements are described. The effect of temperature change on brace loads is discussed and the measured apparent earth pressure for the 60-ft cut is provided. The paper discusses the relationship of lateral displacements of the cut wall to the construction procedure, and compares the lateral wall displacement with both lateral and vertical movement in the surrounding soil mass. Based on observed movement, the method by which displacement was predicted for a nearby 82-ft-deep excavation is described. The performance of the 82-ft-deep excavation has been summarized elsewhere (2).

Jan 1, 1974

By Donald A. Ranta

Every mineral project or mine is based on a geologic entity-an ore (mineral) deposit. A well-defined mineral deposit and its associated geologic characteristics are the only aspects of a project that cannot be altered. Mine plans can be modified to exploit the deposit using alternative approaches and yielding similar results. A variety of processing methods also are often available producing generally comparable results. Major modifications can be made to other aspects of the project without substantially changing project economics. However, all engineering and metallurgical aspects of a mine must be accommodated to the spe¬cific location and geologic characteristics of the deposit. Geologic data and interpretations form the foundation for both mine evaluation and mine production by providing esti¬mates of reserves and essential information for mine planning and process design or control. Proper geologic work requires a keen awareness of and an ability to anticipate the technical requirements of geotechnical engineers, hydrologists, mining engineers, metallurgists, and other specialists. Geologists are inte-

Jan 1, 2008

By C. F. Lee, Bezalel C. Haimson

A 300 m deep test hole at Ontario Hydro's Darlington nuclear plant site, 65 km east of Toronto, was used to determine the state of stress in the Paleozoic limestones (O-22O m depth) and the Precambrian granitic gneiss (220-300 m). The results of the hydrofracturing measurements indicated a state of high horizontal stress along the depth of boring and a consistent orientation of principal stresses in each geologic unit. These results were confirmed by a borehole TV camera survey, and by overcoring tests. The magnitudes and orientations of the measured in situ stresses were used in a feasibility study of siting an underground nuclear plant, and in particular in the geotechnical design of proposed reactor caverns in Precambrian rocks. Their implications on cavern stability under operational and accident conditions were analytically studied, taking into consideration the potential superposition of thermomechanical stresses under loss-of-coolant condition, and the possibility of thermal spalling in the host rock.

Jan 1, 1979

By Mark E. White, John H. McCowan, Michael C. Costello

Minproc Engineers has carried out the design construction and commissioning of thirty two process plants in the period 1978-87. Twenty eight are gold silver recovery plants, and of these twenty two were gold alone and six were gold and silver. In most plants carbon was used for gold adsorption. Desorption has been carried out using the USBM Homestake method, the Anglo American Research Laboratories method, and the Micron Methanol method. Electrowinning has utilised steel wool, stainless steel wool, and aluminium cathodes. Electrorefining using polished stainless steel cathodes is practised. This paper summarises the experience gained in these operations

Jan 1, 1987

By D. Babich, L. Alcorn, E. Spencer, A. Smith

Noise is one of the most pervasive health hazards in mining. A compilation of Mine Safety and Health Administration (MSHA) noise survey data for Fiscal year 1990 shows that approximately 40% of the total samples taken for longwall occupations exceeded the Permissible Exposure Limit (PEL) of 100% [Gigliotti et al. 1991]. In order to properly determine workers’ exposures on longwall coal mining systems, it is necessary to provide accurate baseline measurements for these mining systems. This research was designed to develop guidelines and test procedures for identifying all noise sources that are major contributors to the underground noise exposure of longwall coal mining system workers. Once the high noise sources are identified, promising engineering controls can be tested and evaluated to reduce the noise of the sources. The measurement system used to analyze the noise sources included stationary dosimeters in a documented repeatable pattern and a time-motion study of the cutting cycle and operator’s work cycle. Significant results from the underground measurements show that the highest sound levels recorded are at the stageloader discharge segment and tailpiece controls and remained at about the same level throughout the test.

Jan 1, 2007

By J. Schleifer

On short term, planning techniques require more details to ensure feasibility, giving importance to operation constraints and use of available resources. In GUEMASSA (Morocco), the ore mass is mined by cut-and- fill method. Correct organization requires to forecast a few weeks ahead the schedule of blocks to be mined, in order to respect ore quantity and grade constraints. While operating constraints are tackled, feasibility is assumed with an average production capacity suggesting that resources will be available. In ST-SALVY (France), scheduling operations is not possible if not considering account resource allocation. In any stope within the vertical vein zinc deposit, the cut-and-fill method enables to mine each horizontal slice according to various strategies, de- pending how to use manpower and equipment, and selecting among predefined scenarios known as realistic. For KOFFIEFONTEIN (South Africa), the kimberlite pipe is mined by a sub-level-stoping method. To achieve the production target, precise organization over one month is obtained, using on& resources when available and respecting all mining rules. This combined operation scheduling and resource allocation is called sequencing. While following the BONANZA concept, providing a planning- retrieval process, sequencing offers more. Very detailed, it is possible to check the impact of resource parameters and mining rules. The sequencer, like a simulation platform, enables expertise. Each sequencer must be tailor-made to fit to each specific mine. The next challenge is to produce a generic environment.

Jan 1, 1996

By V. de Ruiter

In the northwestern part of the Netherlands lies the deepest solution salt mine in the world. The company operating the mine is Frisia Zout bv (part of the K+S group). Extracting the NaCl from caverns at a depth of nearly 3000 m has a lot of challenges. Continuously monitoring, among others, the flows, pressures and salt concentrations is necessary to safely and economically mine the salt. A system has been set up at Frisia to be able to monitor the data from a distance. Data has been put in graphs to monitor the trends daily. All gauges are also continuously monitored to maintain accuracy. With this system a better understanding of the mining process has been made and has led to many optimizations.

Jan 1, 2008

By Frigyes Egerer, Pál Bárczy

Introduction Charles III, Holy Roman Emperor and King of the Austro-Hungarian Monarchy, established one of the first mining schools in Europe on June 22, 1735, in Selmecbanya (Schemnitz in German and Banska Stiavmica in Slovakian). The old city, built around the ancient gold mines, is shown in a contemporary engraving in Fig. 1. Charles' historical decree consisted of 13 chapters and included: the deed of foundation, the definition of grants, instruction for educational policy and curriculum, disciplinary rules, and the appointment of personnel. The first professor of the school, Samuel Mikoviny, gave his first lecture the same year, in December 1735. The 250th anniversary of the establishment of the School of Mines was celebrated Sept. 2-4, 1985, in Miskolc. It was attended by representatives of other Hungarian and of several foreign technical universities. A silver medallion (Fig. 2) was issued to commemorate the occasion and a series of lectures

Jan 6, 1986

By P. B. Altringer

The Bureau of Mines conducted laboratory tests to develop a process for recovering a marketable grade of tungsten from the brine of Searles Lake, Calif. The brine contains only 56 parts per million of tungsten (70 ppm WO3). Using ion exchange resins synthesized by Bureau chemists, 98 percent of the tungsten was extracted from the brine and 92 percent of the tungsten vas recovered as a marketable iron-tungsten concentrate containing 44 percent tungsten as tungsten trioxide. Although major technical problems have largely been resolved, research is progressing to escalate testing in a process investigation unit to provide more reliable data for an economic appraisal.

Jan 1, 1978

By Ergin Arioglu, Werner Burger

"SUMMARY The Istanbul Strait Road Crossing Project includes a 3.34 kilometer subsea tunnel excavated by TBM with an excavation diameter of 13.71 m. The tunnel will incorporate two road decks, each employing two traffic lines and shoulder with the daily capacity of 100,000 light vehicles. The tunnel alignment crosses full face rock sections with heavily fractured zones due to tectonic events as well as a long central stretch of difficult mixed face and very variable soft ground conditions. The demanding ground conditions and the large diameter in combination with realized face pressures well above 10 bar required a highly specialized and well adapted TBM. The paper describes the project challenges and the related technical solutions incorporated within the TBM design as well as the real site experience. INTRODUCTION In 2013, a 13.71 m diameter Mixshield was manufactured in Germany for the Istanbul Strait Road Crossing Project. The delivery of the TBM in late 2013 was a major milestone for the Istanbul Strait Road Crossing Project, also known as the Eurasia Tunnel Project. The Eurasia Project (www.avrasyatuneli.com.tr/en) consists of a 14.6 km route including a 5.4 km tunnel segment in its central part crossing the Bosphorus. The 3.34 km subsea section of the tunnel was excavated in closed mode using a Mixshield TBM. The remaining tunnel length is constructed by sprayed concrete lining (SCL) method followed by a cast in place (CIP) lining or by cut and cover (CC) structures for the TBM transition boxes (Figure 1, right). Other project sections on the European and Asian side consist of upgrading and widening surface access roads towards the tunnel. Conceptual ideas of connecting Asia with Europe via a tunnel crossing the Bosphorus have been around for an extended time and only became realistic towards the end of the 20th century based on significant technical developments in mechanized tunneling. Feasibility studies for a new Bosphorus crossing in 2003 and 2005 confirmed and suggested a road tunnel in its present alignment as the preferred solution. Following an international tender process the Ministry of Transport, Maritime Affairs and Communications of Turkey assigned ATAS, a special purpose company formed by Yapi Merkezi (Turkey) and SK E&C (South Korea), to design, build and operate the Eurasia Tunnel Project. The Implementation Contract was signed in February 2011. In 2012, Herrenknecht AG was selected as the supplier for the 13.71 m Mixshield TBM."

Jan 1, 2016

By Neal P. Cochran

The United States is faced with increasing demands for electricity, coupled with continuing demands for crude oil and gas. Superimposed on these' national requirements are our national requirements for clean air and elimination of thermal pollution of our rivers. From the coal viewpoint, this situation is complicated still more by the rapid advances in nuclear power. In this paper, I hope to show a way to use our Western coals as a solution to this involved national problem by producing: 1. High quality crude 2. Low cost power 3. Economic byproducts We could expect these products to be made at one site in an integrated plant that would mine (extract) coal, process it, and convert it to electricity. Perhaps the most important attribute of the plant is its reduced water requirement and the elimination of air pollution from the power cycle. Quite logically, such a plant would probably recover valuable byproducts, such as pipeline gas, sulphur, cement, aluminum, and the like. Although the plant projected in this paper is a conceptual one, it is based on work now underway by Government and industry. Prediction of the future is a most hazardous occupation, but plants such as the one projected are based on current knowledge and can be expected to reach commercial operation in the near term future.

Jan 1, 1967