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By C A. Chaves

During most of its history, the metallurgical industry has been seen as a source of pollution for the environment. However, during the second half of the 20th century, as the world environmental legislation became more protective and the global environmental conscience consolidated, this landscape began to change. Metallurgical activities have become increasingly related to the social and environmental impacts caused by human activities. With the adoption of environmental management in steel plants, there has been a significant change in steel-related activities which have begun to introduce modern plants, managed with environmental, social and productive efficiency. More and more, steel companies search for a decrease in negative impacts of their industrial operations on the environment, fitting them to the current environmental legislation and even increasing productivity and profitability. The steel industry has started to become a clean and more efficient industry. This work presents a case study of a sustainable steel plant project, located in an environmental preservation area. The project includes treatment and reuse of industrial liquid effluents, air emissions control, noise control, recycling, recovery and adequate waste management. It also incorporates production processes using clean technologies, capable of coproducing energy resources which may be used in the plant showing how is it possible to produce steel with environmental and social responsibility and even increase the enterpriseÆs profitability.

Jan 1, 2009

By Fidelis T. Suorineni

Rapid drifting enables quicker access to orebodies, higher productivity rates and a resultant reduction in activity costs. Increased advance rates, by examination of the key components (face preparation and drilling, hole loading and blasting, scaling, mucking and support installation) in the development cycle, and optimizing these processes is a high priority for research in the Canadian mining industry. Support installation time alone is typically 36 to 46% of the total development cycle time. A reduction in support installation time or techniques and alternative scaling strategies could result in significant gains in drift development advance rates. Support Staging and hydroscaling within the drift cycle could offer alternative drift development sequences that could reduce the overall cycle time. MIRARCO?s research into the support and hydroscaling processes for rapid drift development also suggests that there are many other factors (e.g. mine ventilation services) that have a significant impact on the rate of advance. These factors should be considered to promote and manage safe and rapid drift development. Constraints to the rapid drift development processes can only be overcome by sound construction management practices. In other words, the goals of rapid drifting can be achieved by the implementation of contractor-type construction management. This paper examines various constraints and processes affecting rapid drift development and draws attention to other factors affecting safe rapid drift development.

Apr 1, 2005

By AIME AIME

The following changes of address of members have been received at the Secretary's office during the period of Jan. 1 to Mar. 15, 1907. This list therefore supplements the annual list of members corrected to Jan. 1, 1907, and brings it up to the date of Mar. 15, 1907. The names of members who have accepted election during January and February, 1907 (new members), are printed in italics. The large number of changes of address since Jan. 1, 1907, shows the importance of publishing these changes as frequently as possible, and the Bi-Monthly Bulletin has been selected as the means to present this information to the members of the Institute. By a simple method of cutting out these names and addresses and pasting them directly over the corresponding names in the annual list of members, the record can be kept practically up to date, and the value of the list correspondingly increased. For this purpose the changes of address have been printed only on one side of the page. The names of new members, being in italics, are readily distinguished from the others, and can be pasted in approximate alphabetical order on the margins of the pages.

Mar 1, 1907

By J. Wiebmer

The two most important influencers of cost-per-ton in an underground mining machine are its productivity (tons/hour) and its availability-utilization (hours/year). Operating cost and initial price have far less impact. This paper reviews a cost-per-ton sensitivity analysis for underground mining equipment and discusses benchmarks for measuring its performance. The conclusion is that miner-supplier partnerships and the Information Age are the two most significant trends in cost-per-ton reduction.

Jan 1, 1997

By Paul L. Michael

This report presents a discussion of perforance parameters for electronic or active hearing protectors that will meet the needs of underground coal miners. This information is incorporated into a proposed set of specifications that can be used to judge the suitability of a particular electronic hearing protector for the coal mine application. Acoustic and electrical tests were performed on a developmental model of an electronic hearing protector built by the U. S. Bureau of Mines. This model showed only a slight reduction in speech intelligibility which was traced to poorly matched components and in particular to the transducers. Tests of alternative components showed the Knowles BL-1671 microphone to be suitable for this application because of its performance and extremely small size. The Roan-well H-143/AIC earphone was found to have a good frequency response but has the disadvantage of being rather bulky which causes a slight degradation of a low frequency attenuation of the hearing protector. A satisfactory installation of these components in a hearing protector muff was demonstrated and tested. Results of tests of several methods of controlling the sound level under the hearing protector muff showed that a simple diode clipper circuit can be used with only a negligible loss in speech intelligibility for normal-hearing listeners. A commercially available active hearing protector, the British-built ACOS A-9000/2 was examined. This hearing protector provides sound level limiting through a saturating amplifier. Preliminary tests have shown that the performance characteristics of this commercial unit meet many of the proposed specifications so further testing and evaluation should be performed to determine its suitability for use 1n underground coal mines. The recommended test of intelligibility for electronic hearing protectors and other communication systems as used in a coal mine setting is the Modified Rhyme Test (MRT) developed by House et al. in 1965. The suitability and method of administering this test are discussed.

Jan 1, 1976

By J. J. McClelland

The face area of a continuous mining section of an underground coal mine is the most dangerous area in the mine. Workers there are at nearly twice the risk of death or disabling injury than those in other parts of the mine. Despite extensive training of miners and improved equipment and mining methods, fatality and injury rates have remained constant during the past few years. It is clear that advanced research is necessary to apply new technologies or modify work procedures to solve the continuing problem of the loss of lives and the numerous injuries at the mine face. A U.S. Bureau of Mines research program is developing a Reduced-Exposure Mining System (REMS) that relocates personnel operating the mining machinery at the face away from the hazards to a nearby haven of relative safety. REMS uses proven technologies of computer automation and robotics to help control the operation of the mining machines at the face, while personnel are moved away to a nearby, safe control room. In this protected, well-ventilated environment, they can supervise or control the operation of the machines while viewing what the machine is doing using video and graphic display monitors.

Jan 1, 1994

By A Woodley, A N. Danoucaras

In 2012 the Bureau of Meteorology, under the banner of the Water Accounting Standards Board, released the Australian Water Accounting Standard 1 (AWAS 1). This standard has been in development since 2007 with key milestones being the release of the Preliminary Australian Water Accounting Standard in 2009 and the exposure draft of the Australian Water Accounting Standard in 2010. Throughout this period, the Minerals Council of AustraliaÆs Water Accounting Framework has developed concurrently with the Australian standards and the standards have informed elements of the framework. However, the framework is not identical to the standard as the objectives between the two are different. The objective of the Water Accounting Framework is to create consistency in water reporting of the minerals industry and to assist companies reporting to corporate sustainability initiatives. The objective of AWAS 1 is to provide information to water management bodies to facilitate decisions about the allocation of water resources. Companies are to report on an annual basis - not only physical flows of water but contractual requirements to supply and obtain water - regardless of whether the transaction has been fulfilled in the reporting period. In contrast, the Water Accounting Framework only reports on flows that have physically happened. The paper will provide summary information on aspects of AWAS 1 that are most relevant to the minerals industry, show the alignment and differences between AWAS 1 and the Water Accounting Framework and explain how to obtain the information for the AWAS 1 reporting statements.CITATION:Danoucaras, A N and Woodley, A, 2013. Alignment and differences between the Australian Water Accounting Standard and the Water Accounting Framework for the minerals industry, in Proceedings Water in Mining 2013 , pp 85-90 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

"1.0 INTRODUCTIONThese Guidelines reflect the state-of-the-practice of the Deep Mixing Method (DMM) in North America. DMM is an in situ mixing process that breaks down the soil structure; injects binders, fillers and reagents into the soil; and blends them with the soil. DMM is also commonly referred to as Soil Mixing. The final properties of the treated soil in situ are a function of the composition of the native soils and groundwater, the binders introduced, the mixing methods and energy, and the conditions and time of curing. Treated soils generally have increased strength and stiffness and/or reduced permeability relative to the native soils.This document addresses DMM performed by rotating single and multiple axis mixing tools, rotating cutter wheels at the end of a rigid kelly bar, or trench mixing using a rotating cutting/mixing chain around the perimeter of a rigid bar. Binder may be injected through low or high energy (velocity) jets.The treated soils created through wet DMM are heterogeneous mixtures of binder, water, soil, and groundwater. Treated soils produced by dry DMM techniques are a mixture of binder, soil, and the water already present in the native soil.DMM applications described in this document include•,Earth retention•,Liquefaction mitigation•,Groundwater seepage control and containment isolation•,Bearing capacity improvement•,Deep foundations•,Mass stabilization and contamination containment•,Embankment, levee and dam strengthening, and stabilization•,Casing replacementThis document was developed to address deep foundations applications. Use of deep mixing for seepage control is not specifically addressed. The reader is referred to documents prepared by the U.S. Army Corps of Engineers for additional information. Shallow soil mixing and the use of DMM for stabilization/solidification of contaminated soils performed at depths less than 10 feet (3 m) are mentioned briefly. Jet grouting is not covered by these guidelines."

Jan 1, 2016

By J. M. Ortiz, J. P. Bertini

"In mineral resource and ore reserve estimation, several sources of information are generally available, such as diamond drillholes, reversed-circulation drillholes, and blastholes, and originate from one or more sampling campaigns and are analyzed by one or more laboratories. In such a situation, the grade measurements may not have the same precision and one should distinguish between hard and imprecise data.This work aims at studying the impact of data imprecision in resource/reserve evaluation through two case studies on simulated deposits: a porphyry copper deposit conditioned to real exploration and production data, and a gold deposit simulated without any conditioning data. Several geostatistical techniques are used to estimate the grades of selective mining units from exploration samples, including kriging, cokriging, lognormal and indicator kriging. Two types of imprecision are examined— measurements with multiplicative errors and measurements defined as intervals. The results are compared to the simulated grades of the selective mining units from a statistical and economic viewpoint.The study concludes that imprecise measurements should never be discarded because they help to improve the estimates, and that simple methods such as kriging are as efficient as more sophisticated ones for resource/reserve assessment. Finally, a few indications on how to diagnose and model the data imprecision are given."

Jan 1, 2005

By Yael Miron

Coal mines that undergo self-heatings, and specifically mines that sustain both floor heave and self-heatings, would benefit from the use of sealants to minimize air ingress to susceptible areas. The U.S. Bureau of Mines (USBM) evaluated three sealant systems for this purpose, bentonite-water mixtures, silicate gel, and guar gum gel. The guar gum-based gel was the only sealant that possessed the desired properties of elasticity, ease of preparation, adaptability to the mine, and a long life. In addition, since the gel consists mostly of water, it could quench or cool nearby heatings. Optimal formulations were determined in laboratory tests, and then tested in the USBM Safety Research Coal Mine. Two for-mulations resulted in stable gels that lasted for at least 12 months in the mine. Semicontinuous preparation of gel using an eductor was evaluated and appears feasible. Although guar gum gel is expensive, selective use to prevent heatings in specific areas would be cost-effective, both in terms of productivity and enhanced mine safety.

Jan 1, 2010

By W. Kempson

"As has been noted on numerous occasions, the vertical shafts being sunk around the world are all tending to get deeper as we seek to take advantage of higher grades of minerals which can sometimes be found at greater depths. One of the challenges with these deeper shafts is the requirement to supply services to the mine’s operations at depth as well as the requirement to dewater the mine. Both the supply of water and the dewatering of mines is generally done using piping. With the greater shaft depths, this piping is now required to contain higher pressures as well as to accommodate changes in temperature resulting from normal mine operations. This paper will discuss the requirements for the design of high pressure piping in deep vertical shafts. The discussion will start with the general definition of the systems and the detailed design requirement. Once this is clearly outlined, we will discuss the options available for fulfilling these requirement as well as the advantages and disadvantages of each of the systems. We will finish with the installation recommendations and provide a basis for the maintenance of these systems. INTRODUCTION Piping in vertical shafts is used to provide a number of services in underground workings. These services vary depending on geographical location and the type of the ore body which is being mined. For example, in the Zambian Copper mines, one of the largest requirements for in shaft piping is for dewatering. Similarly in the Gold deposits in the West Wits basin as well as the deep level Copper deposits in Arizona, one of the largest uses for the piping is the supply of a cooling medium to underground workings to create a safe working environment (this can in the form of water or of glycol depending on the application). In South Africa, systems were installed which used the hydrostatic head which is generated from supplying chilled water to mines whose depths exceeded 2,000 m below surface. This chilled water was supplied as a closed system, allowing for high pressures to be generated which was then used to supply useful work (for example, Rock Drills, Face Cleaning and other ancillary services) whose power was traditionally supplied by compressed air or electricity. This system was initially researched by Chamber of Mine in South Africa. The design pressure range of these systems is 14 MPa to 18 MPa."

Jan 1, 2019

By David Chastka, Isidro Rivera, Shawna Von Stockhausen, Idit Zarchi

The City of Santa Cruz Water Department is replacing the existing Newell Creek Dam inlet/outlet works at Loch Lomond Reservoir in the San Lorenzo Valley. The project will improve the City’s overall operational efficiency, improve system performance, and improve the safety and reliability of storage for the City’s drinking water supply. The project comprises new inlet works* (three new inlets that control and convey flows into and out of the reservoir, and an intake control building), an inlet/outlet tunnel with a 48-inch conduit to convey flows into and out of the reservoir, and a new outlet structure at the toe of the dam. The outlet structure includes a release point for energy dissipation of emergency drawdown flows, a connection to Newell Creek Pipeline, and beneficial releases into Newell Creek. The project also includes a new dam seepage collection and monitoring system and appurtenant structures such as a culvert bridge over the spillway plunge pool to improve access to the new outlet. Notable complex project components include in-water work to connect the new intake shaft pipes to the three new inlets. The project includes one major milestone with a work window regulated by environmental permits that could only be amended/ extended with approvals from those agencies. If not met, the milestone work would have caused significant delays (potentially up to one year) to the project.

Jun 13, 2021

By Harvey S. Mudd

WHEN talking about Europe it is well to endeavor to keep politics and economics apart but they have become so intermingled in recent years that the discussion of one topic inevitably leads to the other. Economic influences formerly prevailed over politics but today national and international economies are governed by political forces. Commerce in raw materials, food, and manufactured products is now so restricted by governmental controls that the capacity of the world to produce and to consume, to exchange goods and to pay for them, cannot be gauged by the past or predicted by a multitude of experts. In prewar days there were some yardsticks but today there are none. Thus it is hazardous to make forecasts, for in all fields of human effort the world has been cast upon an uncharted sea.

Jan 1, 1947

By Ulrich Maidl, Jamal Rostami, Ulf Gwildis

Tunnel Boring Machines (TBM) have more or less become the preferred method of tunneling in various ground conditions and Programmable Logic Controllers (PLC) or microprocessors are standard features on TBMs to monitor and record various sensory systems on the machine providing the possibility for machine automation and control. The data collected from these sensory systems and channeled through PLC is stored for real-time analysis or use by the operators. Based on typical construction specifications, part of the information collected in the process is shared with the project management team representing the owner. Machine data automatically acquired during TBM advance is typically processed by specialized software to offer the project team data visualization and evaluation options. Interfacing with Geographic Information System (GIS), Computer-Aided Design (CAD), 3-D geologic model, instrumentation data bases, and Document Management Systems (DMS) allows for developing Building Information Models (BIM) of the tunnel’s as-built condition. Application of Artificial Intelligence (AI) processes such as Machine Learning (ML) have already been used for analysis of data, including performance prediction of hard rock TBMs, and exhibited the potential of big data analytics in improving the productivity of the operations. This paper outlines anticipated disruptive technological advances with implications on geotechnical exploration, TBM operation, face condition tracking, subsurface risk allocation, and claims management in the future.

Jun 13, 2021

By Lijun Liu, Yingwei Li, Jianhua Liu, Jinhui Peng

"As essential equipment in the metallurgical industry, current air heat exchangers cannot meet the requirements of high temperature heat transfer. In this paper, an energy efficient air heat exchanger, based on accumulation of the heat generated by microwave absorbing materials, is presented according to heat transfer theory and principles of the microwave field. A tubular shaped heat exchanger was designed and built up through temperature-rising curve, and experimental research of microwave high-temperature air heat exchangers was carried out. It was found from experiments that the tubular shaped heat exchanger fabricated using material B could be used for high temperature heat transfer system, and equilibrium temperatures could reach up to 457—485?.IntroductionHeating or cooling of air by heat exchangers is commonly practiced in a wide range of industries including construction, chemical, machinery, textile, printing, and dyeing [1-3]. Generally such heating or cooling of air is achieved in pipe heat exchangers. There are several drawbacks for such heat exchangers, namely, (i) the limitation of temperature to which the pipes can be heated, (ii) tendency to oxidize at high temperature, and (iii) poor strength of metallic pipes at high temperature. These limitations do not allow pipe heat exchangers to be operated at high temperatures [4-6].Microwave heating of inert solids, which are stable at high temperature, is a possible solution to achieve high temperature of the medium in air heat exchangers. It is well-known that microwave heating is an efficient, clean, safe, easy-to-control heating method. Microwave heating utilizes the dielectric and magnetic properties of a material. When microwaves penetrate and spread into the dielectric material, electrons, ions, etc move in the internal electromagnetic field, while the elasticity of inertia and friction impede these movements. This results in a significant thermal effect, increasing the surface temperature rapidly [7-8]. This paper studies mainly design and experimental research of microwave high-temperature air heat exchanger."

Jan 1, 2011

By M. J. Ferrante

Relative enthalpies of CuBr from 298.15 to 1,301 K were measured at the Bureau of Mines to provide thermodynamic data needed for the advancement of mineral technology. The temperatures of transition were measured by differential scanning calorimetry (DSC) and the standard enthalpies of transition[ (IlH~r) by drop calorimetry. The combined results gave reversible transitions at 657 K with llH~r= 1.10 kcal/mol, at 741 K with lm~r == 0.51 kcal/mol, and at 759 K with an enthalpy of fusion (AH~) of 1.22 kcal/moL ] An anomalous increase in heat capacity preceded the first crystal transition at 657 K. Tabulated values are listed for the standard relative enthalpy, heat capacity, entropy, and Gibbs energy function from 298.15 to 1,500 K. Standard relative enthalpies are also given in equation form and combined with thermodynamic data from the literature to derive values of standard enthalpies of formation and Gibbs energies of formation.

Jan 1, 1984

By Dodd SF

Valuation of mining companies and their underlying assets prepared by brokers' analysts are, by necessity, approximations. The reliability of the valuations is entirely proportional to the quality of available data, the reliability of forecasts and the nature of underlying commodity price assumptions. The latter is perhaps the greatest single cause of gross variations in company and asset earnings estimates and- valuations. Assumptions are often necessary regarding commodity price achievement based on commodity hedge positions. Public disclosure from listed companies provides a sound base from which to project earnings, cashflows and balance sheets. The uncommon disclosure of projected production and cost schedules often reduces the reliability of future estimates. The application of reserve and resource estimates is contentious with practitioners applying differing weightings to importance of resources in estimating mine lives (and therefore cashflow streams). Valuation methods applied in equity markets usually focus on relative value and the identification of pricing anomalies. The commonest ""rules of thumb"" applied in the valuation of mining companies (and therefore their underlying assets) is with the use of year specific price/earnings (P/E) and price/cashflow (P/CF) ratios, with low multiples suggesting undervalued assets, high multiples overvalued situations (but these rules can often be clouded by market expectations of underlying commodity price movements). Another simply applied valuation tool is to examine the examine the value placed on reserves and resources by the market. Inexpensive gold in the ground (expressed as $ of market capitalisation per ounce of reserves or resources) might indicate a buying opportunity, but the market does discount the value of gold in the ground prior to mine development and where development risk is perceived.

Jan 1, 1994

By Adam Powell, Salvador Barriga, Matthew Earlam

"The inert anode is a key enabling technology for dramatic energy and emissions reduction in extractive metallurgy. In molten salts, the materials challenge is nearly insurmountable: the anode must conduct electrons at high temperature in a pure oxygen and molten salt environment. A solid electrolyte, e.g. zirconia, between the salt and anode removes the molten salt stability constraint, and can act as a container for a liquid metal anode. This can be liquid silver for oxygen-generating inert anodes, or several metals for natural gas-fueled anodes; it is possible to switch between these modes. The solid electrolyte brings several other benefits: it eliminates molten salt contamination of the anode gas, creates a reducing environment enabling low-cost steel vessels, increases current efficiency, and eliminates carbon contamination of the product. New developments presented here, including current collector and low-cost anode designs, amplify these benefits for producing aluminum, magnesium, rare-earths, and other metals.IntroductionReactive metals such as magnesium, aluminum and rare-earths play increasing roles in efficient transportation and clean energy. In response to new fuel economy standards, automotive OEMs are planning large increases in use of aluminum and magnesium to reduce vehicle weight. Rareearth permanent magnet motors and generators exhibit better power-to-weight and efficiency than induction motors and other designs, making this today's primary motor technology for hybrid and electric vehicles, and for wind turbines. Nickel metal hydride (NiMH) batteries with lanthanum are dominant in hybrids. In 2011, transportation comprised 28.6 out of 103.1 EJ of US energy consumption [1] and 1,845 out of 5,471 million metric tonnes (MMT = 109 kg) CO2e of US greenhouse gas (GHG) emissions [1], creating big targets for economy-wide reductions.Unfortunately processes for making reactive metals for these applications are very inefficient and heavily-polluting. In primary aluminum production, Hall-Heroult cell electricity use [2] is more than double the reaction enthalpy due to heat losses through frozen cryolite side-walls and anode gases, graphite anode plants add significant energy use and GHG emissions [2] (see Table 1). Magnesium is even worse: silicothermic reduction by the Pidgeon process in China produces about 85% of the world's magnesium using coal or coke gas [3]. Chloride electrolysis begins with high-purity MgO and requires carbochlorination or hydrochlorination and costly chloride dehydration [4]—rendered unnecessary for aluminum by the Hall-Heroult cell. Production of neodymium and lanthanum with graphite anodes leads to inconsistent carbon content: small cells make 1 kg batches for analysis, sorting and sale by carbon content, with very high labor and analysis costs. And vertical electrodes give no incentive to reduce anode effect: some reports indicate that China's rare-earth metal industry emits more CF4 and C2F6—with global warming potential (GWP) 6500 and 9200 times CO2 respectively—than China's aluminum industry [5]."

Jan 1, 2014

By C. Mawdsley

The Tata Steel mill at Skinningrove in the North East of England produces top hat sections for mineshaft guides in sizes 102 and 150 mm. The top hat section is the technically preferred shaft guide choice for modern deep mine shafts. This paper explores the relative service performance of top hat and square hollow section guides in service. Comparative corrosion performance is reviewed and the paper describes work commissioned by Tata Steel (as Corus) undertaken by Aker Kvaerner Engineering to evaluate relative winding speeds, relative loads and fatigue life in service. The experience of supply to UK Potash mining is discussed and the future view of high capacity hoisting and larger section size market need and availability is assessed.

Aug 1, 2013

By S. F. Featherby

"This paper traces briefly the historical development of coal handling systems to meet the needs of a rapidly developing thermal power generation technology. The wide range of operating requirements is demonstrated by comparing and contrasting the Wabamun GS of Calgary Power Ltd. and a typical modern Ontario-Hydro thermal plant. The problems of safe storage of large tonnages of coal in stockpiles are discussed, together with recommendations for stockpile management. The development of coal bunkers and their management is discussed in detail, together with future trends in the industry."

Jan 1, 1966