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By Samuel H. Dolbear

NOT WITHSTANDING the extremely low ebb of business activity, the nonmetallic industries have fared somewhat better than some other branches of mining. The average price level in nonmetallics, although far from satisfactory, has resisted any cataclysmic fall such as has been suffered by copper and other metals. Stocks, also, though too abundant, represent no corresponding overhang of the market, which should result, in some branches, in a more rapid recovery. Research work has continued in some industries with interesting developments.

Jan 1, 1933

By J. L. Carr

Every year, severe injuries and fatalities occur when a miner is struck or pinned by a continuous mining machine, shuttle car, scoop or other piece of mobile mining equipment. Proximity detection systems offer a means to prevent these types of injuries and fatalities by sensing the presence of a miner and disabling machine motion. Although hundreds of these systems are installed and in use in operating coal mines, the influence that coal has on the electromagnetic fields associated with these systems has never been rigorously quantified. NIOSH researchers have conducted tests to measure whether the proximity of coal has a significant influence on a popular design of proximity detection system. The system tested utilizes a low frequency magnetic field generator that would be mounted on the mining machine. At the NIOSH Safety Research Coal Mine in Pittsburgh, researchers measured the performance of a simplified proximity detection system of this type first on the surface then underground at varying distances from a coal face. Analysis of these measurements shows that the presence of coal does not have a measurable impact. Disclaimer: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Reference to specific brand names does not imply endorsement by the National Institute for Occupational Safety and Health.

Feb 27, 2013

By M. Moats

Copper electrowinning operations have dramatically improved their ability to produce high quality copper at low costs over the past several decades. Even so, some fundamental understandings are still lacking, which could allow operates to run more efficiently. For example, a rule of thumb exists that estimates a current efficiency loss of 2-3% per gram per liter of iron in the electrolyte. While several laboratory studies have been performed that demonstrate this rule of thumb is likely true, no definitive relationship exists. In this paper, the first steps in developing a definitive relationship are presented. The effective diffusivity of ferric ions in synthetic copper electrowinning solutions was measured using chronoamperometry and the Cottrell equation. The effective diffusivity of ferric ion was determined as a function of electrolyte concentration and temperature. Synthetic electrolytes were then used in laboratory scaled copper electrowinning experiments where relationships were found under stagnant conditions between current efficiency and solution composition.

Jan 1, 2009

By Vinay Kumar, Manis Kumar Jha, J. Rajesh Kumar, Archana Kumari, Rekha Panda, Jin Young Lee

Rare earth metals (REMs) play a significant role in the manufacture of permanent magnets, fluorescent lamps, catalysts, medicines, super alloys etc. Recently, China, which controls 97% of world trade in REMs, imposed restriction on its export. Consequently, the global demand of REMs is escalating and is expected to exceed the supply by 40,000 tonnes annually. Present review paper reports the flow-sheets of commercial processes based on pyro-hydro and hybrid techniques as well as systematic research for process development to recover REMs from primary and secondary resources. This review paper also reports the recommendation and future prospective to fulfill its demand and supply gap keeping in view environmental prospective.

Jan 1, 2014

By Don Dodds

Iron Mountain Mine Rehabilitation Project Brief History The Iron Mountain Mine is located in Northern California approximately 12 miles northwest of Redding. The ore body is a large, very dense pyritic intrusion, discovered in 1860, and initially minded for silver. The silver played out quickly and 34 years later the ore body was mined for copper. Copper mining was scheduled to cease in 1939, but WWII prolonged the closure. After WWII, the pyrite ore was mined to produce sulfuric acid. In 1949 when large amounts of cheaper sulfuric acid were being generated by the oil industry the underground mine shut down. Little was done with the site conditions until 1970 when the U.S. Bureau of Mines began monitoring the pH of the effluent. The initial pH readings were around 2.0. This was lower than anyone expected. Laboratory tests showed that when the ore from the mine was submerged in water, the pH of the water would stabilize above 4.0. However, the pH got steadily lower. In 1989 with the ph around 0.7, the U.S. Environmental Protection Agency (EPA) required the owner to build a capture and treatment facility. During this initial period, the majority of the effort was spent on the treatment plant. The relationship between the mine owner and the EPA was basically an adversarial relationship from the very beginning. In 2001, North Pacific Research was hired to upgrade the capture and control facility. The general layout of the Iron Mountain Mine is shown in Figure 1.

By Patrick M. Y. Waye

As mines utilise more automation in mining operations to improve efficiency and safety, a corresponding increasing demand is placed on the transport of information. Some of the recent technological advances in underground telecommunications are described for various data, voice and video applications. In particular, two new innovative underground communication systems are described, one with high speed data at 30 Mbps and the other for mine wide evacuation and safety applications. The high speed data system incorporates stateof- the-art data networking technologies and the existing leaky cable narrow band radio channels. The new system provides over the same basic infrastructure the high speed data network at 30 Mbps TCP/IP Ethernet with 100 Base-T interconnection, plus 32 narrow band radio channels. The second system is a system for mine wide evacuation with "through the earth" communication infrastructure. Emergency situation can be communicated to and from all the miners within seconds through a central control location. The technology involved does not require leaky cable or any other similar transmission media installation. Many applications are possible, including warning miners of emergency situations, mine rescue operation to communicate with trapped miners, regular reporting from miners working alone.

May 1, 2001

By B. Unver

Effective strata control is a prerequisite for maintaining an efficient mining operation. If the strata in the vicinity of an opening are not controlled effectively, it is impossible to perform a safe, efficient and economical operation. In this paper, the reasons and outcome of instability problems observed in roadways opened in clay and marl at the Bolu Colliery of Yeni Çeltek Establishment are investigated. Roadways under examination were located in a syncline causing high residual tectonic stresses. Factors affecting the instability have been studied thoroughly by examining geology and tectonics of the area, establishing convergence measuring stations to understand in situ behaviour of supports and laboratory tests to determine engineering properties of samples taken from nearby convergence measurement stations. As a conclusion, a new production strategy and a new support system are recommended to maintain stability.

Jan 1, 1999

By Birger Schmidt

INTRODUCTION Conceptual design of the first Exploratory Shaft (ES-I) for the Nuclear Waste Repository in Basalt (NWRB) began in July 1981; detailed design began in February 1982, and was largely completed by December (RKE/PB, 1983). The intent was to begin shaft construction by January 1983. The site had been prepared at that time, a construction manager selected and on board, the starter hole excavated and lined, and steel casings were under procurement. Government policy changed, however, and construction was halted before the drill rig started turning. Construction is now planned to begin in 1988. ES-I is a part of the site characterization program for the NWRB. The shaft will be used to develop production data and related information relative to drilling shafts at the site near Richland, WA, and to provide access to the repository horizon for site characterization and testing. The early program called for one shaft and some 330 m (1000 ft) of drifting. The program has since expanded to include a second shaft (ES-II) and more extensive drifting and testing. Currently, both shafts are planned to be 1.8 m (6 ft) in finished diameter, but studies are underway to determine if the second shaft should be larger. The drilling method was selected for shaft construction primarily because it offered a significantly shorter construction period than conventional shaft sinking using freezing and grouting. The finished drilled shaft will be lined with a continuous steel lining. Personnel are safer during construction with a drilled shaft than with a conventionally sunk shaft. The drilling method

Jan 1, 1987

By David Fernando de Carvalho

Este estudo de caso foi solicitado por uma grande mineradora brasileira à Chemtech Engenharia, com o objetivo de avaliar um projeto de um Transportador de Correia de Longa Distância na fase conceitual, onde se buscava a otimização do consumo energético, mínimo investimento financeiro inicial e redução dos custos operacionais. O resultado deste estudo de caso foi usado como diretriz no projeto básico do equipamento, além de ser usado como referência para outros projetos similares.

Sep 25, 2017

By S. J. Swart

This paper discusses the principles and application of risk assessment and management as the basis for environmental management within the mining industry. Unlike in other industries, mines are required to obtain closure certificates in terms of section12 of the Minerals Act, which should ultimately release them from further environmental responsibilities. It is emphasized that the concept of environmental risk assessment and management, when applied correctly will mean that the mine will be identifying and managing environmental issues beyond those set by current legal requirements and management strategies. The focus shifts from conventional minimum legal compliance management to management of real environmental risks. The advantage of this approach is that the perceived ?shifting of legal and management goal posts? due to changing environmental laws or management principles, will not influence or dictate the mine?s short or long-term management objectives or actions, mine closure funds can be more accurately determined and mine closure should become a relatively simple procedure. The risk assessment approach has been applied to the planning of mine closure at Iscor?s Durban Navigation Collieries (Durnacol) in Kwa-Zulu Natal and certain key risk issues such as the long-term risk of water pollution from coal discard dumps have already progressed to fully quantitative risk assessment. This paper will discuss the process, which has been followed to date, with particular emphasis on the most recent phase, namely quantitative risk assessment and management of pollution from coal discard dumps. It is believed that the approach that is being pioneered at Durnacol and which overcomes some of the more obvious deficiencies of both the EMPR and the traditional IEM process will ultimately serve as the model for all responsible mines in South Africa. It is also believed that this approach will enable the authorities to issue closure certificates with the confidence that there will be no unforeseen surprises in the years after closure.

Jan 1, 1998

By A. Garassino

A pile design was performed for a thermal power station in Egypt and more than 4000 piles were to be driven. Technical economical reasons suggested the choice of driven composite LACOR piles designed for very high specific loads. Some uncertainties on the behaviour of the pile soil system suggested to perform a test on an instrumented pile. Scope of the test was to verify the possibility of developping the required bearing capacity within the range of the allowable pile settlements values and the effect of the pile joint enlargement on that portion of skin friction to be developped by the upper pile section.

Jan 1, 1991

By J Deen, P Sterk, W Forsyth

Homestake Mining Company has made a firm commitment to develop a functional and cost effective perimeter blasting program. The goal of the program is to develop smooth, sound walls in all development ends. A good perimeter blasting method will improve safety, reduce waste rock handling, allow easier support installation and reduce scaling time. All the benefits will contribute to an overall reduction in total development costs.

Jan 1, 1997

By Wellington Pereira Inácio, Fernando Wypych, Sergio Neves Monteiro, Artur Camposo Pereira, Rafael Marangoni

"The efficiency by which an applied load is transmitted from the matrix to reinforcing fibers in a composite depends on the fiber/matrix adhesion strength. This is determined as the interfacial shear strength, IFSS, which may be measured by means of pullout tests that measure the force needed to pull a single fiber out of a block of material simulating the composite matrix. Different techniques are used to perform pullout tests. The objective of this work was to characterize the IFSS of sisal fibers embedded in epoxy matrix through the determination of the critical length pullout curves. As the main results, a relatively small critical length was found for the sisal fiber/epoxy pullout specimens, corresponding to a weaker IFSS. This was compared to other results applying different pullout techniques. Scanning electron microscopy observation identified the mechanism responsible for the weak sisal fiber adhesion to the epoxy matrix.IntroductionSynthetic fiber reinforced composites is today one of the most successful class of materials with increasing industrial applications from house appliances to large airplanes like the modem Airbus 380. However, environmental issues are revealing serious drawbacks related to the fabrication, use and post-use discard of these composites. For instance, the thermoset polymer composite reinforced with E-glass fiber, known as ""fiberglass"" has an energy-intensive fabrication associated with a surplus emission of C02, which is responsible for global warming [1]. Moreover, the glass fiber is considered toxic and also causes long term pollution after being discarded."

Jan 1, 2011

By Ren Xiangwen, Shi Xuefa, Shao Mingjuan, Ye Jun, Yang Yaomin, Li Bing

"The Mid-Atlantic Ridge (MAR), one of the archetypes of slow spreading ocean ridges, extends from the Arctic Mid-Ocean Ridge southward to the Bouvet triple junction making up a significant proportion (~ 40%) of the global oceanic ridge system. During the past few decades, many hydrothermal fields like TAG, Logatchev, Ashasze were discovered along the northern part of the MAR, whereas the southern part, which makes up one third of the ridge (6000km), shows little documentation of hydrothermal mineralization, except for three sites: Site 4°48! the Nibelungen Field, and Lilliput. During March to May 2011, following discovery of three new hydrothermal fields during the 2nd Leg of COMRA's 22 Cruise of the R/V DayangYihao, the 3rd and 4th Legs found another two high temperature hydrothermal fields (SMAR15°S, SMAR26°S), one low temperature field, and several fields with strong turbidity and temperature anomalies in the water column. In this study, we present a preliminarily study of the mineralogy and isotopic geochemistry of the sulfides from SMAR 15°S and SMAR26°S.SMAR 15°S is situated in a SE-NW offset depression of an axial neovolcanic ridge in the median valley, with water depth of about 2793m. In the water column around this field, strong turbidity and temperature anomalies were detected. Ten-meter tall venting chimneys, hydrothermal mounds, as well as a large amount of hydrothermal vent shrimp were also observed and recorded by ROV and deep-tow camera surveys. The samples collected from this field include sulfide chimney fragments, massive sulfides and basaltic rocks. Based on the major metal and the mineral assemblages, three types of sulfides have been identified: 1) Zn-Fe rich sulfides with abundant wurtzite and pyrite zoned fragments, 2) Cu-Fe rich sulfides with much isocubanite and pyrite assemblage, 3) Fe-rich sulfide with massive pyrite fragments. These indicate that this field has undergone at least three phases of mineralization during the venting history."

Sep 1, 2014

Prefeasibility planning and cost estimation of conveyor systems has historically been undertaken by comparing fixed plant transport requirements to that of similar systems in service. This paper describes the development of a prefeasibility conveyor technical design and cost estimation application using Microsoft Excel Visual Basic for Applications (VBA) platform. The application tool known as D-Convey (Dachshund Convey) was developed with the goal enabling the end user:- to develop a technical model for conceptualised conveyor systems,- to perform economic analysis on the developed technical model, and - to conduct a comparative and risk analysis.An Excel VBA based platform was utilised to draw upon both the analytical and graphical capabilities of a spreadsheet. Some of the features of D-Convey system include a revolutionary dynamic graphical help system, known as the 'information pane' in lieu of traditional help files as well as the use of familiar graphical user interface elements such as the MS Office 2007 task ribbon. The D-Convey system incorporates material database allowing for mass handling prefeasibility estimation in other industries; it has been validated at a local quarry.

Dec 6, 2010

By J. Maiti

This study examined the group differences in accident susceptibility among underground coal mine workers accounting for their personal and workplace characteristics. A logistic regression model was used for this purpose. Data were collected from five underground coal mines for a period of four years. The case study results revealed that different age and experience groups of workers bear no significant differences in their accident susceptibility; however, the workplace location and occupation groups show significant differences in their risk of injuries. It is inferred based on the logistic model results that among the three occupation groups, the face workers are more susceptible towards accidents/injuries compared to the haulage and other workers. Key Words: Mine Safety, Accident Susceptibility, Group Differences, and Logistic Regression.

Jan 1, 2001

To provide operators of large-opening mines with a ventilation planning tool that will help them develop a healthier, safer, and more efficient ventilation system in the underground workplace.

Jan 3, 2006

By William Hustrulid

Pre-split blasting is a primary technique for creating slopes with a minimum amount of unwanted damage to the remaining rock mass. Rock slopes created in such a way have both safety-related and economic advantages. The applications extend from road cuts to rock quarries to large open pit mines. For example, as deep open pit mines approach the end of their operating lives, slope steepening is one option to be considered. To be able to safely achieve and maintain steepened final slopes, good blast design techniques must be available and applied together with close operational control. Pre-split blasting is an important element in this slope creation process.

Jan 1, 2007

By Paul M. Wiltcher

This paper discusses how benefits in engineering design can be achieved from combining existing GRP concrete design guidelines with carbon steel design codes primarily made possible due to the increase in the constitutive properties of modern composite rebar or GRP. It also examines the technical and practical considerations necessary to both construct and ensure the integrity of composite rebar during transportation and handling on site and the measures taken by Franki-Cementation Joint Venture to ensure the safe deployment of the GRP in the workplace on the Noord/Zuidlijn Project in Amsterdam between 2003 and 2006.

Jan 1, 2006

The technical parametrization of reserves is a technique which has made an important contribution to the definition and the calculation of optimal mining projects. Its applications to a new open-pit optimization program have already been presented in various papers (François-Bongarçon and Maréchal (1976); François-Bongarçon and Guibal (1981)). The present paper gives a brief description of the general problem of parametrizing reserves before going into the details of the practical algorithms used in two typical cases, i.e. open-pit mining and mining between hanging wall and foot wall.

Jan 1, 1982