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By D. C. Edwards

In an age where customer service and quality drive today's industry and business, no service or product is exempt from these demands. Industry and business are streamlining everything from people to equipment and today have a heavier reliance on the performance and quality of their assets and equipment, (one of the keys to staying competitive). In the mining process industry, the centrifugal slurry pump is a key piece of equipment that keeps product moving and aids in generating revenue for its owner. The continued improvement and customer success lies in a team effort between the mining industry and the pump manufacturers. We, the pump manufacturers, need to keep improving our designs to further extend the life of our pump with fewer failures and promote to our customers proper maintenance of the pumps to continually keep unexpected failures to a minimum. Strict equipment maintenance, as thoroughly demonstrated by the military, is key to the long life and success of any piece of equipment. In the often harsh duty of the centrifugal slurry pump, maintenance is something that requires "attention to detail". No area of the pump is exempt from attentive maintenance. Here, discussions will focus on the areas of the mechanical drive end, wet end, seals, and extended pump shut down and start up. There has not been a slurry pump designed to maintain or repair itself. So in effect, each pump warrants able bodied maintenance persons to maintain them who continually observe all the rules of safety. Prior to any maintenance discussion or action, the issue of safety should always be addressed. Here, as with everywhere, the same rules apply. Work at a safe pace, note all safety precautions, use associated safety equipment and personal protective attire, observe all tagout and lockout procedures, and most importantly, be aware.

Jan 1, 1996

By Christopher Mark

Area wide pillar failures, or “squeezes,” were once fairly common in underground coal mines. While rare today, they do occur. This paper describes seven case histories that were investigated by MSHA Technical Support. They occurred across the range of US coalfields, in both longwall and room-and-pillar mines, and involved development mining, pillar recovery, longwall panel extraction, and multiple seam interactions. Significant lessons from each are discussed.

Jun 25, 2024

By R. H. Grau

The National Institute for Occupational Safety and Health (NIOSH) has conducted research to improve the ventilation of large-opening mines. The research has demonstrated that the ventilation of large-opening mines improves significantly by including ventilation requirements in the mine planning process and implementing some practical techniques during mining. Planning the location of long pillars to reduce the number of crosscuts between intake airways and return airways, positioning auxiliary fans in their proper locations, and establishing ventilation stoppings with minimal leakage all significantly improve the ventilation of large-opening mines. Mine operators that adopt these techniques in the mine ventilation plan will reduce mineworkers? exposure to airborne contaminants.

Jan 1, 2008

By James E. Lawver

The agriculture industry has made great strides during the past decade to increase agriculture yields through increased use of fertilizers. Increased use of fertilizers may prevent or at least delay mass starvation due to the alarming increase in world population. Phosphate was added to soil as a plant nutrient in the forms of calcined bones at least 2 000 years ago, (1) and man has used phosphate minerals as a source of fertilizers in one form or another for at least 100 years. During 1977 the world produced about 116 million metric tons of phosphate rock, with about 86% used for fertilizers and another 4% for animal feed supplements. More than three-fourths of the total production comes from the United States, Morocco, and the Soviet Union. From a mineral beneficiation point of view, the major sources of phosphate rock and the methods of beneficiation can be classified as follows. Marine deposits not containing appreciable carbonate minerals, marine deposits requiring a francolite carbonate mineral separation, igneous deposits not containing appreciable carbonate minerals, and igneous deposits, requiring an apatite carbonate mineral separation.

Jan 1, 1978

By Manuel Bernales, Aldo Leon, Alexandra Carlier, Bern Klein, Andre Xavier

Mining companies and governments at both the local and national levels recognize that Participatory Environmental Monitoring and Surveillance Committees (PEMSC) are necessary mechanisms for meaningful engagement at the community level. In many cases, PEMSCs are established as volunteer initiatives by mining companies or by the mining communities themselves. In Peru however, they can also be recommended by the government as way to address social conflict. Most PEMSCs are launched while a mine is in operation and have the objective of monitoring both water quality and quantity. Many established committees are currently evolving and adopting a more comprehensive approach, as well as expanding their initial scope from a river or micro-basin focus and watchdog agenda, to a broader regional integrated resources management view. This paper examines the origins of Participatory Environmental Monitoring and Surveillance Committees in Peru. It also discusses the typology of these committees, and the scope of their work. Furthermore, it looks at the challenges faced by these committees, as well as existing opportunities for mining companies, governments, and civil society. Finally, this study presents a governance model that could contribute to the long-term existence of these committees. This discussion is further informed by the results of a national workshop that took place in October 2016 in Peru, in which over 200 representatives from 22 monitoring committees, government and mining companies participated.

Jan 1, 2017

By K. H. Singh

The addition of new data and corrections can be made under the control of a simple editing session. All programs for this system are written in FORTRAN and executabe "MACROS".. After the addition of new data, the whole file Is reinitialized to update the binary file and cross-reference tables. Updating the binary file involves rerunning the initializing program. The creation of graphic plots like cross sections and plan views is menu-driven from a terminal and very user-friendly. Small files containing not more than 10,000 entries (survey and assay points) are suitable for this setup, particularly for computers with less than 2 Megabytes of real and virtual memory. The largest file processed contained 35,000 lines of survey and assay information and required 4 megabytes of virtual memory. Working with this size file slows down the time for the creation of plots and cross sections. Another independent system is more akin to a financial type of data base. It was installed in one Anaconda mine as part of the operation's inventory, warehouse, day-pay payroll, and purchasing data bases. It is a highly hardware-dependent system, in particular, IBM's CICS/VS (Customer Information Control System/Virtual Storage). This is a true relational data base that optimizes storage requirements, supports online inquiry, update, data entry, and data security. While this system has been tested and proven in accounting applications, it requires programming expertice in PL/I and other CICS utility programs. It is well suited for huge data bases (like the 35,000 lines of data), but cumbersome for small engineering files.

Jan 1, 1985

By Carolina Bruecker, Axel Preusse

"The topic of ground movements in Germany has been studied extensively in the past, especially in the field of active mines. The active hard coal mines were finally shut down in 2018 in Germany and lignite mining is expected to take place only until 2038. The so-called long-term liabilities of the mine operators in Germany include, among other things, the long-term guarantee of stability and thus the monitoring of ground motion.So far, the economic use of underground mining in Germany was mainly the supply of raw materials. In the future, the underground storage of compressed air, methane, or hydrogen will play an important role in renewable energy supply and climate change. Therefore, underground storage space will become more important and spatial planning is essential to ensure availability of safe underground openings for the various options of environmentally friendly energy storage.However, this renewed usage of underground openings may also bring new and sometimes unknown challenges of geomechanical influence. On the one hand, the aftermath of hard coal and lignite mining will be an increasing challenge in mining subsidence engineering. On the other hand, new possibilities due to underground spatial planning may lead to subsidence and/or heaving of the upper surface.INTRODUCTIONBoth hard coal and lignite have a long tradition in Germany. The Prosper Haniel mine in the Ruhr area was closed at the end of 2018 after 150 years, which signalled the end of hard coal production in Germany. Lignite mining still takes place in the Central German, Lausitz, and Rhineland districts. However, lignite mining in Germany is expected to be phased out gradually by 2038 (MDR, 2019). With the closure of these mines, however, mining damage is not over. The long-term consequences of mining, which extend far beyond the closure of the mines, are associated with the liability and responsibility of the individual mining companies. The so-called eternity burdens on the mining company continue to apply. In the field of lignite production, the discontinuation of dewatering and the resulting possible elevations of the surface will be a relevant topic for the future of mine surveying. The same applies to the hard coal mines, which are partially flooded in Germany and therefore require extensive monitoring of soil movements in the future.The discontinuation of energy from hard coal and lignite calls for a change in the energy mix. With the renewable energy revolution in Germany, the focus is on a sustainable and environmentally compatible climate and energy policy based on renewable energies. Sustainable use of the subsoil, both natural and anthropogenically produced cavities, will play an essential role in the objectives of this policy. For example, disused mine cavities can be used to store electricity from renewable energy sources. (Umwelt Bundesamt, 2018) These functions will again cause classical ground movements such as subsidence and uplift, but will also bring new challenges for the mine surveyor. Challenges can be underground cavity exploration in inaccessible areas or legal aspects of underground competition."

Jan 1, 2019

By O. A. Bascur

Current competitive demands on the process industries stimulate the need for improved operating efficiencies and compliance to stricter governmental regulations. Emerging information technologies allow narrowing the gap between management business objectives and the process control level. Benefits come from enhanced energy management, operating costs reduction, enhanced scheduling of activities, reduced quality giveaway, enhanced market driven production and enhanced decision making. Plant management systems integrate economic performance monitoring by controlling the business rather than just throughput and product quality. Sound business based decisions about how to operate the plant can be achieved by adequate dynamic performance monitoring at the plant level and the enforcement of the desired targets at the process control level. This paper describes some of the key requirements to implement a process management system to meet stricter process performance standards. Extensions are made to facilitate conforming with regulations established by various governmental and industry monitoring agencies.

Jan 1, 1993

By Warren G. Burres

or more than 50 years the Portland Cement Association has represented the United States cement industry in matters relating to the technology and use of cement and concrete. Interestingly enough, PCA?s emphasis has been on concrete and its uses rather than on Portland cement. The cement industry realized long ago that cement is basic and serves its fundamental purpose as an ingredient in concrete. Cement could never be successful if concrete were not. Work with the users and specifiers of concrete had to be done at its end point of application--in a building, bridge, dam, highway or home. PCA, over its half century of existence, has been dedicated to this job. I should like to talk to you today on the less technical side of concrete--what it has been--what it is today--and what it can offer in future construction. Concrete, in many forms, has a long background extending from such notable historic times as the Roman Empire. Here, concrete made from pozzolanic cement from the slopes of Mt. Vesuvius was used to construct the Coliseum, home of the Roman circus; for the Appian Way, the ancient forerunner of the Interstate system; and the miles of aqueducts throughout Europe, many of which still carry water. In 1811 Joseph Asppin, an English bricklayer, made the first modern cement by the artificial mixing of pulverized limestone and clay materials. Ht,

Jan 1, 1971

By W. F. Quirk

The Missouri-Oklahoma tripoli district was discovered and first mined in 1869 near Seneca, Missouri. Tripoli is a microcrystalline form of high-purity silica that is porous, light- weight, and friable and is derived from a parent siliceous sedimentary rock from which soluble minerals have been leached. Tripoli deposits, 2 to 20 feet thick, occur in cherty limestones of Mississippian age beneath 2 to 10 feet of overburden. They are mined in open pits up to 9 acres in size. The color of tripoli is white, but it also commonly is light pink or red where stained by red iron oxides and clays. Ground tripoli is used commercially as an abrasive or in buffing and polishing compounds and is prized for such physical characteristics as its abrasiveness, porosity, permeability, absorption, and specific gravity.

Jan 1, 1978

By Gary W. Hudiburgh

The gangue in some magnetite ore bodies contains feldspar; the alkali content of the feldspar reduces the usefulness of these iron ores. One method of decreasing the feldspar content in magnetite concentrate is froth flotation. The amine flotation of feldspar from magnetite concentrate was investigated using zeta potential measurements, Hallimond tube flotation tests and laboratory-scale flotation tests. The zeta potential of various feldspars (microcline, albite, anorthite, oliqoclase and anorthoclase) were determined as a function of pH; the point of zero charge ranged from pH 1.4 to 2.5. Hallimond tube flotation tests using two amine reagents were conducted on the feldspars. Hallimond tube flotation tests using six amine flotation reagents were performed on the cobber tails (quartz, albite and microcline) from a magnetite concentrating plant; in all cases, over 85 percent flotation recovery was obtained at pH 8 and 10-5 to 10-4 [M] collector addition. Laboratory-scale (667 grams) flotation tests were performed on the magnetite concentrate in an attempt to float the feldspar which had reported to the concentrate. The effects of three different collectors, two levels of collector concentration, three pH levels, starch and HF acid were investigated.

Jan 1, 1975

By Hamed Khodadadi, Hamid Ghadiri

The ball mill grinding circuit has widespread application in mining, metallurgy, chemistry, pharmacy and research. It faces some challenges because a grinding circuit is a multivariable system in which high interaction between loops, variation of system parameters with time, and time delays are problems. In this study, a fuzzy logic self-tuning proportional–integral–derivative (FLST-PID) controller based on an improved disturbance observer is designed for control of ball mill grinding circuits. It is combined with an improved disturbance observer (IDOB) to eliminate system interaction, attenuate internal and external disturbances and compensate the effect of system uncertainty on the performance of the ball mill grinding circuit.

By K. L. Gabby

Since mercury is chemically similar to silver, it tends to dissolve along with the silver and gold during cyanide leaching. Ultimately mercury is recovered along with the silver as mercury/silver/gold amalgam which requires retorting to remove the mercury prior to refining the silver and gold. A possible approach to separating mercury from silver and gold in cyanide leach solutions is to take advantage of the replacement reaction between [Hg(CN)4]2- and Ag2S, which results in precipitation of mercury as HgS while dissolving silver as [Ag(CN)2]-. Results are presented demonstrating that mercury can be removed from cyanide solutions with high effectiveness, while, at the same time, recovering additional silver in solution. Initial experiments with static flasks in the laboratory showed a high degree of mercury removal could be achieved. Results using actual metallurgical plant products in bottle roll tests indicate the process works on a larger scale, but also results in significant gold losses if the solution being treated has high gold levels, such as carbon stripping pregnant eluent solution.

Feb 23, 2014

By R. M. Reyes, D. Negrete, G. Herrera

First Majestic Silver Corp’s La Encantada Silver Mine is a producing mine with a capacity of 3,000 tonnes per day. The La Encantada team is currently constructing two small-scale caving mines, including the San Javier breccia caving mine. The new mine is constructed within a mineralized breccia body composed of clasts of varying sizes and with very poor rock quality. Due to this poor rock quality, primary and secondary supports are required to support both the development and production stages. Since the proximity of the new mining levels to existing old workings, correct selection of the support system and proper production controls, instrumentation, and monitoring are very critical to maintain the stability of the pillars and fortification elements. An increased ground deformation due to the load transfer during the production stage is expected. This report reviews the primary and secondary support elements used in the different stages of mining, the monitoring of ground deformation, and the steps taken to analyze and visualize the collected data in order to enable the geotechnical team to manage caving stress and maintain pillar stability. INTRODUCTION First Majestic Silver Corp. (“First Majestic”) is a Canadian mining company focused on silver production in Mexico that operates six producing silver mines, including La Encantada Silver Mine (“La Encantada”). First Majestic acquired La Encantada in 2006. La Encantada is located in the northwestern portion of the state of Coahuila, in northern Mexico, in the municipality of Villa de Ocampo. The mine lies in the northern part of the Sierra Madre Oriental physiographic province. The mine location is shown in Figure 1. La Encantada is a producing mine, with a mill processing capacity of 3,000 tpd, and a 4,000 tpd capacity cyanidation leaching circuit equipped to process fresh underground ore and old tailings amenable to be reprocessed. The mine is currently employing several mining methods, including overhand cut and fill for narrow veins, small mantos, and other minor deposits. A subset of caving methods are applied on the larger, but weak, mineral deposits, such as at the San Javier breccia and La Prieta breccia. La Encantada consists of vein, manto, breccia pipe, and chimney deposits with concentrations of silver, lead, iron, and zinc in oxidized mineralization enclosed by calcareous sedimentary formations of Cretaceous age. At deeper levels, there is sulphide mineralization in skarn with zinc and silver concentrations associated with a granodiorite intrusion.

Jan 1, 2019

By Elisa Comis, Barbara Bitetti, Julien Pepiot, Stefano Lione, Francesc Rich

The new Lyon-Turin railway project involves the construction of a 57 km twin-tube tunnel between France and Italy. Pini France (project leader) and Systra-SWS are the designers of Construction Site 8 (CO8). This part of the project includes the construction of the tunnel portal on the Villard-Clément platform, two 2.8 km long tubes of the base tunnel in the direction of Saint Martin la Porte, the cross-passages between tubes and the niches. This paper presents the general approach followed to design the temporary support for the base tunnel, cross-passages, and technical rooms. The design of the temporary support accounts for the variability of the ground and water conditions, the excavation attended behavior, the construction planning and the identified geological hazards that could be encountered along the alignment. Particular attention is paid to the intersections between the tunnels both in terms of numerical modelling and construction methods and phases. Two types of intersections are present in the project: the intersections between the cross-passages and the base tunnel and the intersections between the base tunnel and the niches. 3D models have been developed for the tunnel intersections.

Jun 23, 2024

By Andrew Thomson, Peter Wright

"A section of a London Underground expanded segmental lined tunnel constructed in the 1970’s progressively deteriorated after 2001, with extensive radial joint spalling and mid-segment cracking. As part of the PPP contract Tube Lines Ltd and their partners carried out various analyses of the tunnel, including analysis of laser scans of the tunnel, geotechnical testing through the tunnel walls, geotechnical desk studies, real-time monitoring and even full-scale segment testing. This paper discusses the behaviour of the tunnel lining in this setting, the causes of failure and the lessons that can be learnt from this rare example of a tunnel which was progressively failing in service. It is finally noted that a replacement tunnel lining was installed during night-time possessions and completed in 2015. INTRODUCTION In 2003, Tube Lines Ltd. was established under a Public-Private Partnership (PPP) scheme to provide maintenance services and upgrade projects for London Underground (LU). The Deep Tube Tunnel Knowledge and Inspection Programme comprised the assessment of all tunnels, shafts and other underground structures. This included a number of lengths of tunnel constructed using segmental concrete linings. First used by LU in the 1960s, the savings both in cost and speed of construction led to concrete linings replacing cast iron for new tunnel construction in all but a few cases. During the initial scoping phase of this programme, inspections identified potential issues with the expanded concrete segmental linings on the Jubilee line. The inspections found a number of segments with surface spalling (Figure 1a), which did not appear on the post-construction defect records. These were generally relatively shallow, up to 40mm deep, spread over a wide area of segment. These were different to spalls caused by handling damage, which are typically localised at segment corners. Subsequent inspections over the following years identified an increasing number of segments with these types of spalls as well as an increased incidence of longitudinal mid-segment cracking (Figure 1b). The increasing occurrence of these defects was hypothesised to be caused by tensile stresses developing in the vicinity of the joint."

Jan 1, 2016

By George R. Powe

If Campbell County, Wyoming were an independent nation, it would rank fifth in the world among countries with known coal reserves. Only the United States, Russia, mainland China and West Germany would have greater volumes available. Not too many years ago that statement would not have seemed important, because oil and natural gas had become our nation's principal fuels. Western coal deposits, particularly those of the Powder River Basin in Montana and Wyoming, and which underlie virtually all of Campbell County, were largely unknown. But recently, in response to the three-pronged stimulus of vanishing gas reserves, rising petroleum prices, and clean environment statutes, these vast deposits have been delineated and have become, in the minds of many, indispensable to our goal of energy independence. Not only does western coal lie in thick seams near the surface where it can be mined in huge quantities at low cost, but also it possesses another coveted attribute in this age of environmentalism: low sulfur content. At Burlington Northern we count ourselves at the forefront of those who believe this coal is essential to any hope for the government's "Project Independence." But to that belief we add another article of faith. We are convinced the economics of unit train delivery of this incredibly immense resource make it the only transportation system that can help us achieve energy self-sufficiency in this country.

Jan 1, 1975

By J. K. Szymanski, Val Srajer

In this decade mining companies in western Canada have searched for reliable and inexpensive ways to improve mine productivity. Truck dispatching systems, equipment vital sign monitoring and sensing, vehicle guidance systems, have all been considered. In this paper the off -highway vehicle monitoring systems used or planned to be installed at surface coal mines in western Canada are described. The monitoring systems are divided according to their function and application; installation and testing procedures are described, as well as the economic benefits to the mining operation.

Jan 1, 1989

By Saied S. Navid, Michael A. Piepenburg, Richard F. Escandon, Robert C. Lindsay

INTRODUCTION Phase I of the Los Angeles Metro Rail Project, known as MOS-1 (Minimum Operable Segment-1), is the first phase of the 27 km± (17 mi) subway starter line. MOS-1 is currently under construction and involves approximately 6.4 km (4.4 mi) of subway, five stations, yards and shops routed through the downtown area of Los Angeles. The project will form the initial heavy rail backbone of a more extensive light and heavy rail transit system planned for the greater Los Angeles area in the future. Construction Contract A-171 is one of 4 tunnel contracts within MOS-1 and involves construction of twin tunnels running from the downtown metropolitan area west to MacArthur Park. The heavily populated and developed downtown area, potentially gassy ground conditions, and the possibility of undocumented abandoned oil wells in seismically active southern California made the design and construction of Contract A-171 a uniquely interesting project. This paper summarizes the construction history to date (December, 1988) including design geotechnical considerations, tunnel support design, as-built geologic conditions, shield tunneling performance through soft ground, and ground response. The findings presented herein may aid in the design and construction

Jan 1, 1989

By Yuanhong Qi, Xun Fu Wang, Tao Fu, Kunkun Cui, Yingyi Zhang, Jie Wang, Junmao Qie

With the sharp decrease of sulfide nickel resources, the nickel laterite is becoming more attractive as nickel oxide, nickel matte, and nickel-iron. This study investigated the mineral phase structure, chemical analysis, thermal properties, and element distribution characteristics of the rotten rock layer deposited in the Southeast Sulawesi Ophiolite Belt. The results show that the nickel laterite deposited in Southeast Sulawesi Island, Indonesia, belongs to the typical high-nickel and low-iron garnierite-type laterite. The concentrations of nickel and iron of the nickel laterite are 1.99 wt% and 17.55 wt%, respectively. The serpentine, olivine, clay, chlorite, hematite, and magnetite are the major minerals, and the pyroxene, actinolite, limonite, and chromite are the minor minerals in the nickel laterite in Southeast Sulawesi, Indonesia. Serpentine and olivine are the main nickel minerals with an average nickel concentration of 3.65 wt% and 1.73 wt%, respectively. The Fe and Ni have homogeneity and symbiosis in the serpentine and olivine, and their concentrations are often positively correlated.