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By M. J. R. Morris

THE year 1939 has seen the iron and steel industry driving for efficiency with unabated zeal. "Efficiency" is here used in the sense of enabling the customer to do more with less, either supplying him with more economically priced steels or with higher priced steels that will do a job more economically. The plain carbon steels have been improved tremendously in quality be- cause of recent control tests. All steel companies have been urged to hold to .closer chemical control, closer standards, soundness, and more control on grain size, and now attention is being directed to closer control of hardening properties. Better control of open- hearth operations undoubtedly will result in an increase in the application of special carbon steel. Further, with a better understanding of quenching, the present trend to study the quenching of this class of steels will be ex- tended. These steels will then be used for purposes to which they are best suited. Utilization of special carbon bars and large shapes seems to be developing less slowly than special car- bon in the form of strip. There are many reasons for this and the future development of this trend will be important. Continued development of the manufacture of parts from strip and sheet to replace forgings, and of formed; structural members such as channels or welded pipe, is notable. Special carbon sheets with nonaging properties have been produced during the year; they maintain a higher degree of ductility over a longer time and are less sensitive to the changes which took place in the former product when stocked.

Jan 1, 1940

This paper endeavours to lay as concisely as possible, before the members the salient features of local gold milling practice, and to point out in what respects this practice differs from that of other large mining camps. This is essentially a free milling ore the gangue being quartz and the gold occurring in a coarse form. At times the ore crushed contains a good deal of slate, the latter imparting to the tailings a somewhat leaden hue.Small amounts of sulphides, chiefly iron pyrites, and at times smaller quantities of arsenical pyrites, zinc blende, and galena are contained in the stone. The average amount of sulphides contained in the ore cannot well be ascertained, as the concentrate obtained in all cases contain too much silica to form a basis of calculation...

Jan 1, 1902

By Viviane Tavares

The liquid crystal display (LCD) are currently known by its vast application in electro ? electronic devices, amongst them can be detached the devices of TV, laptops, electronic date, calculators and even though the mobile telephones (mobiles). The mobiles are changed more frequent of the TV for example, this happens due to the technology advance. With the constantly mobile exchange, the batteries, printed circuit board and liquid crystal display accumulation its become an environmental problem. To minimize the environmental impacts caused by mobile telephones residues are considered the segregation process of the LCDs main components, to goal to recover the recycle material. This process involves the use of treatment ore techniques with disc, hammers and balls mills. The process with best efficiency (about 98%) of LCD glass release was the hammers mill. The glass recovered can be used in the glass recycling and the sand substitution in the production of concrete blocks.

Jan 1, 2009

By Gabsoo Kim, Rulin Yang, Dave Kay

Blast vibration data, such as PPV are usually scattered. In many cases, plots of PPV versus the charge weight scaled distance are so scattered that useful trends from different blast designs cannot be identified. The scattering of the data may be attributed to the inaccuracy of the PPV measurement, the definition of the scaled distance from a multiple-hole production blast, and the measurement of distances and charge weights. The error from vibration measurements is one of the major contributors to the scattering of the plots. If accurate monitoring is conducted, improved design options may be identified. This paper documents two case examples that compare different vibration sensor couplings. The first case shows mounting accelerometers at spots that protrude from the ground, compared with the sensors that were mounted on a flat ground surface. The second case compares data from loose-sand buried geophone with that from sensors coupled to the ground using concrete blocks.

Jan 1, 2014

By M. J. Beus, B. Stewart, S. Iverson

Synopsis U.S. Mine Safety and Health Administration (MSHA) accidents statistics have identified ore-pass hazards as a significant safety problem in U.S. underground metal mines. The statistics show that nearly 75% of injuries are directly or indirectly related to pulling or freeing of ore-pass chutes, the use of hand tools in ore passes, fails of broken rock in ore passes and structural failures of chutes or gates and ore-pass walls. Researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) are investigating hazards in and around ore passes in hard rock mines. Risk assessment methods, such as fault-tree analysis, have been employed to identify the most probable causes of orepass failures, define research priorities and analyse the factors that result in malfunctioning and unsafe ore passes. Static and dynamic loads are being measured in a laboratory setting with the use of a reduced-scale orepass mock-up. Field tests are being initiated in mine ore passes to determine static and dynamic loads. Data from the test ore passes are being compared with data from the mine to characterize true system behaviour. Computer modelling with the use of closed-form solutions, finite-element analyses and a newly developed particle flow code predicts static and dynamic leads from the flow and the impact of ore and waste in the ore pass. Preliminary results indicate that dynamic impacts from ore and waste rock might be considerably greater than expected. The total static load is substantially less than is typically used fur the structural design of chute and gate support members. It is suggested that damping factors, normal and shear stiffness and mass frictional characteristics have a significant effect on particle flow and resulting impact loads. This is being verified with the use of results from laboratory tests, field tests and particle flow analyses. Ore passes are vertical or steeply inclined openings in a rock mass through which ore and waste are transported and where they mar also be stored. A typical underground mining system is shown in Fig. 1. The arrows indicate the locations of ore passes and loading pockets and their relative configurations. The control of material flow is potentially one of the most hazardous operations in underground mining. According to MSHA data. most of the ore pass-related accidents in the U.S.A. are associated with the loading-unloading cycle and removal of blockages from ore passes. In particular, attempts to free ore hang-ups have resulted in multiple fatalities. The hazards are obvious; there is uncertainty as to when the ore will break loose and miners are unable to escape falling rock to a safe location. Although ore passes and chutes and gate systems for underground metal and non-metal mines roust meet the requirements specified in the U.S. Code of Federal Regulations (CFR). Parts 57 and 75, recent structural failures of ore-pass linings and gates have underlined the lack of adequate ore-pass design standards available to both MSHA enforcement staff and mine engineers. Because of the importance of an ore pass to the safe operation of a mine design criteria need to be assessed and new guidelines developed. Researchers at the Spokane Research Laboratory of the Nationals Institute for Occupational Safety and Health (NIOSH) are investigating hazards in and around ore passes in hard rock mines and studying design criteria for ore passes. The near-term goal is to conduct laboratory and field experiments and computer modelling to evaluate the ore-pass design criteria currently used. Literature searches, field site

By D. Kachongo, Y. Cheng, A. Kashala, D. Samal, G. Mitshabu

Many copper processing flowsheets in the Democratic Republic of Congo include the leaching of oxide ores containing copper and cobalt, copper solvent extraction, copper electrowinning, and precipitation of cobalt salt. Recently, cobalt price gained momentum, driven mostly by the fast-growing electric vehicles battery market. The ore blending scenarios tend to prioritise high cobalt grade ore, whatever the content of copper and other impurities. Therefore, many copper solvent extraction circuits are running below design capacity. The variability of feed induces a variability of the leach solution with respect to copper, manganese, and silica contents. It is thus important to adjust hydrodynamic and metallurgical parameters of the solvent extraction plant to optimise metallurgical performance, production cost, and the quality of the copper electrolyte. This paper presents some results on how solvent extraction plant parameters have been managed in two solvent extraction plants running with lower than designed copper input. INTRODUCTION Referring to a report of the chamber of commerce of the Democratic Republic of Congo (DRC) the online publication Agence Ecofin (2019) indicated that the DRC ranks in the fifth position of the world top copper producing countries with over 1.2 million tons produced in 2018. The same year, 66% of the world’s cobalt was produced in the DRC at over 106,000 tons. If the political situation remained stable and the new tax regime introduced in 2018 did not deter private investors, copper production could reach 1.4 million tons/a in 2020 as pointed out in Mining.com (2019). Forecast figures for DRC cobalt production vary widely depending on analysts. The DRC online magazine Actualité.cd (2018) referring to a ministerial source forecasts over 141,000 t cobalt/a for 2020. The reality will depend on many factors, including the selling price, the supply compared to the demand, and finally the reaction of investors to the new DRC tax regime. The growing electric vehicle batteries market has been the major key driver of the price of cobalt. The five years historical cobalt price graph in figure 1 from infomine.com (2019) shows that the price of cobalt peaked at over 40 USD/lb in the first quarter of 2018. Cited by the online Magazine Creamer Media, Smith (2019) has indicated that the long-term demand of cobalt will likely remain strong.

Jan 1, 2019

By Eric Low

Raising capital by issuing debt or equity is necessary in almost every corporation. In the field of corporate finance, the raising of capital is a heavily-studied topic. However, some of what is studied on this topic in corporate finance is not applicable in the mining industry. There are also many financing options that were created for the mining industry such as flow-through shares, prepaid forwards, and royalty sales. The cyclical nature of the industry makes the risk-return profile of financings more difficult to estimate than in other industries. Additionally, the methods used to assess firm value are different than other industries, as the values of orebodies are not included on balance sheets. For precious metals companies, which are a hedge against most other securities, there are additional complications with determining investor expectations and cost of equity. This thesis puts forth a decision-making framework to explain mine financing choices from the perspective of mining companies. The approach is threefold. First, all of the major equity and debt financing instruments available to mining companies are presented and analyzed. Each financing method is assessed on a wide range of criteria. Next, these concepts are applied in case studies of four companies: BHP Billiton, Barrick Gold, Teck Resources, and Noront Resources. For each company, the overall choice of financing methods is shown and analyzed. The effect of financing choices on the weighted average cost of capital (WACC) is calculated. The final section deals with case studies of individual mine finance decisions during the past two years.

May 1, 2011

By M. C. Azar, W. B. Mason, G. L. Anderson

Eminent domain overview Eminent domain is the power of the Government or a municipality to take property for public use without the consent or acceptance of the owner. Typically, the agency taking the prop¬erty will make an offer, hoping the owner will immediately accept and allow work to begin. If a mutual resolution regard¬ing its value cannot be reached, how¬ever, the municipality will institute a condemnation action in court seeking possion of the property. This is when the problems begin. The power of the Government to take the subject property is limited by Federal and state constitu¬tional requirements to pay "just com¬pensation" for the property. The exact nature of an owner's prop¬erty has been the subject of much debate and discussion. It is generally under¬stood, though, that property is consid¬ered to be "every kind of right or inter¬est, capable of being enjoyed and recog¬nized as such, upon which it is practi¬cable to place a money value" (US vs. 53 114 Acres of Land). A taking, for condemnation purposes, is considered to occur whenever there is a substantial interference with the free use and enjoyment of the property. Rarely is the necessity for the taking ever challenged and more rarely is the taking ever successfully challenged. When a taking occurs, it is not only the fee owner who is entitled to compen¬sation. Every person holding an interest in the subject property will be recog¬nized. Thus, all persons who at the time of taking have a compensable interest in the property will be made parties to the case (Swanson vs. US). Minerals, like all other interests in land, are recognized as property rights, giving the owner the power to dispose of them as he or she sees fit. Thus, the only remaining considera¬tion is only "just compensation." Ex¬actly what "just compensation" is has been difficult to define. Generally, it is that amount of money that will "put the person in as good a position as the per¬son would have been in had the taking not occurred." The owner must not be forced to sacrifice or suffer by receiving less than full and fair value for the prop¬erty. Every element that effects the value of the land and that would influence a purchaser must be evaluated. Courts have employed a variety of techniques to determine just compensa¬tion but have generally relied on market value as the standard for measuring compensation to the owner. The deter¬mination of market value is based on sales, income, costs, and use. These factors have been employed in various ways but can be summed up as: -The highest estimated monetary price the property will bring if exposed for sale in the open market with a reason¬able amount of time allowed to find a purchaser who is buying with knowl¬edge of all the uses and purposes to which it is adapted and for which it is capable of being used. • The amount the property would bring if it were offered for sale by one who desired, but was not obliged, to sell, and was bought by one who was willing, but not obliged to buy. • What the property would bring in the hands of a prudent seller, at liberty to fix the time and conditions of sale. • What the property would sell for in negotiations resulting in sale between an owner willing, but not obliged to sell, and a buyer willing, but not obliged to buy. • What the property would be rea¬sonably worth on the market for a cash price, allowing a reasonable time to affect a sale. (Michigan Standard Jury Instructions). Special consideration regarding mar¬ket value is given when the taking is only partial, rather than complete. An example of this partial taking is when a state highway cuts across the northern half of a parcel of property, leaving the rest behind for the owner. A variety of problems can be immediately seen. In a partial taking, the owner is permitted to recover not only for the property taken, but also for any loss in the value of the remaining property. The measure of compensation for partial taking purposes is generally the difference between the market value of the entire parcel before the taking, and the market value of what is left of the parcel after the taking (Michigan Stan¬dard Jury Instructions). Determining the partial taking value for mineral bear¬ing lands is the difficult issue.

Jan 1, 1989

The Bureau of Mines is active in programs pertaining to solid waste disposal and land reclamation. Nine reclamation projects of mining companies and six projects of the Commonwealth of Pennsylvania were investigated to provide information on the procedures, costs, and results obtained from reclamation projects of bituminous coal-waste disposal areas. Refuse disposal costs of mining companies ranged from 9 to 28 cents per ton-mile, and quantities disposed of ranged from 600 to 4,500 tons per day. Spreading and compacting the refuse at the dump site ranged from 3 to 20 cents per ton. Cost of covering with soil and planting ranged from $750 to $1,646 per acre. Total costs of reclamation for the Pennsylvania projects ranged from about $1,800 to more than $15,000 per acre. Refuse preparation costs ranged from $772 to $5,550 per acre. Soil covering and planting costs ranged from $1,083 to $5,086 per acre. The best results were obtained by soil preparation and conditioning prior to planting. The type and depth of soil and effect of climate were also factors.

Jan 1, 1973

By K. Morsi

Carbon nanotube (CNT) reinforced metallic composites have been recently generating significant scientific interest, due to their expected superior properties compared with other composites. Out of the metallic matrices investigated for reinforcement with CNTs, aluminum has received considerable attention. A major problem has been the dispersion of CNTs in metallic matrices. This paper discusses preliminary results on the mechanical dispersion of CNTs in aluminum powder, powder processing, stability and characterization of aluminum dispersed with CNTs at reinforcement levels equal to and below 5 wt.%.

Jan 1, 2009

By Kausik M. Sinha

Hydraulic stowing, which is being practiced in several major coal producing countries to deal with adverse mining conditions, usually permits almost 100% coal recovery from underground mines with minimal and controlled surface subsidence. It can be implemented in the US coal mines to reduce the severe effect of land subsidence and at the same time improve the cost of coal production, both of which are major setbacks for the coal industry in the USA

Jan 1, 1989

By Keila Gonçalves, Aline Tavares, Danielly Couto

"The sulphide copper deposits from the Carajás area (North region of Brazil) were generated by the percolation of hydrothermal fluids in volcanic and granitic rock and are denominated as IOCG deposits (iron oxide copper-gold deposits). During these hydrothermal events a wide variety of gangue minerals such as amphiboles, biotite and fluorite were formed. These gangue minerals are enriched in fluorine and chlorine which are deleterious elements in the copper concentrate. Chalcopyrite and bornite are the main copper-bearing minerals and they can occur in veins, in brecchia or disseminated in gangue.The study, which included bench scale flotation tests and minipilot plant tests was aimed at improving the fluorine rejection in the flotation process during the flowsheet design for one of these Carajás sulphide copper deposit. All of the study was supported by quantitative mineralogical techniques such as QEMSCAN and the use of a scanning electron microscope (SEM).This paper describes and discusses the results obtained in the metallurgical tests and emphasizes the importance of the quantitative mineralogical characterization during the process conditions optimization and flowsheet design.INTRODUCTIONIron oxide copper-gold (IOCG) deposits encompass a wide spectrum of sulphide-deficient low-Ti magnetite and/or hematite ore bodies of hydrothermal origin and normally have important copper sulphide reserves. In the Carajás mineral province, located at the southeast part of the Amazon Craton in Pará State (Brazil), there is a variety of world-class (>200 million tonnes) Fe-oxide Cu-Au deposits (e.g. Salobo, Cristalino and Sossego), whose genesis has been assigned to hydrothermal fluid percolation in volcanic and granitic rocks. Figure 1 displays the location of the Carajás area.The hydrothermal thermal fluid composition was extremely variable. It may have contained gases, salts (brine) and metals. The metals were carried as various complexes and it is thought to have involved sulphur, chlorine and fluorine containing species. This resulted in some minerals formed during the hydrothermal alteration having high fluorine and chlorine contents. These elements result in smelter penalties in a copper concentrate because they cause the smelter off-gases to be more corrosive."

Jan 1, 2011

By Brotzmann K, Turner RE, Philp DK, Rusden RC

New approaches in the last decade have led to the supplemental use of raw coal as a direct energy source in several iron and steelmaking processes. The dependence on more expensive coke and electricity is being progressively reduced. The Technology Venture of Klockner Werke and CRA has pionered several of these developments and is pushing ahead to processes for scrap melting and direct smel- ting of iron where coal is the ONLY energy source. Such complex developments depend strong- ly on the experience gained in the simpler but related processes for coal use already in operation. The longer term implications of a successful coal-based direct smelting process for the world steel industry are substantial.

Jan 1, 1986

By Tianjiao Luo

Some literatures discussed on how to recycle the various reagent, but the discussion on how to reuse the waste liquid directly is very little. How to reuse the waste liquid directly was researched in this paper. Firstly, the waste liquid should be filtrated to remove the impurity; then some quantity of H2O2 solution was dripped into the waste liquid to pretreat it; finally, CuSO4solution was added into the treated waste liquid and the pH was adjusted to about 12, then some HCHO solution was added into the waste liquid, in which the treated carbon fiber can be plated. The morphology and composition of coatings were investigated by means of Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), the deposition rate was mensurated by the way of dissolution. The results indicated that, the plating effect was basically identical with new plating solution, and the solution is stable, and the plating rate is still about 0.8µm/h, and the copper coating is even and combines closely with carbon fiber. According to this way, the waste liquid can be reuse 5~7 times.

Jan 1, 2006

By Basem Sh. Hazzan

In the last four decades significant effort has been devoted to designing piles in expansive clay soils. Nevertheless, only a scant effort has been devoted to the elimination of heave forces acting on the upper part of lightly loaded piles. For this purpose, an investigation site was established in Karmiel in Northern Israel. On this site sixteen unloaded cast-in-situ piles, both uncoated and coated, were installed in a moderately expansive clay soil in the end of summer 1996. The piles were executed to different depths ranging between 2m and 7m and were observed over a period of 27 months. Another nine unloaded cast-in-situ bored piles were installed at the end of summer 1998 for carrying out pullout tests. These piles were embedded two meters from the ground surface. Results obtained from observations and from full-scale static pull out tests showed that separating the piles from the surrounding clay in the active zone by a twin walled sleeve eliminated the heave forces significantly. The scope of the work is, determining of the elimination degree of the heave forces due to the provision of the above sleeve.

Jan 1, 1999

By H. Cay, J. Zachwieja, T. Esplin, R. Ravenelle, T. Olsen-Tank

Barrick Goldstrike mine utilizes a carbon-in-leach (CIL) circuit to simultaneously leach gold into solution with cyanide and adsorb the gold-cyanide complex onto activated carbon for further refinement. If the gold bearing ore contains a significant amount of native carbonaceous material, gold cyanide can be adsorbed at these sites instead of onto the desired activated carbon and the gold is effectively lost to tailings in a detrimental process known as "preg-robbing." The preg-rob effect is considerably reduced by treating the ore with a surfactant, which is hypothesized to adsorb to and passivate the native carbon surfaces. Past laboratory and pilot studies have consistently demonstrated significant gains in gold recovery after treating carbonaceous ore with surfactant. With success in bench and pilot scale testing, a plant trial was conducted at Barrick Goldstrike to evaluate the feasibility of using an alkoxylated fatty amine surfactant (Ethomeen T/12) to aid in the leaching of high preg-robbing ores. This paper analyzes the performance of the surfactant during the plant trial in addition to the problems that occurred during the trial period. Suggestions for improvement are also discussed.

Jan 1, 2014

By Charles Zdazinsky

Over-break is undesirable in underground civil construction because it excessively damages rock along the perimeter of the tunnel, which directly influences the cycle times of advancement. A quicker cycle time for each process is required to optimize the operation and therefore minimizing over-break is essential for operational success.

Jan 1, 2015

By Chris Bennett, Drupad Desai, Kirit Mevawala

INTRODUCTION The design/build (D/B) philosophy of contract delivery is neither new nor unusual when it comes to at-grade, elevated or high-rise structures. But when it comes to constructing underground facilities, there were no examples to be followed in early 90sin the continental United States or its territories. When DMJM+HARRIS was selected as general architectural and engineering consultant for the Tren Urbano (TU) project in Puerto Rico, one of the requirements of the Federal Transit Administration (FTA) for funding commitment was to use TU as a demonstration project utilizing design/build contract delivery method. Now fifteen years later, New York City Transit (NYCT) has instituted a similar requirement for their first Tunnel Boring Machine (TBM) contract for the Second Avenue Subway. As with most construction mega-projects, lots of things have happened and there were several lessons learned from the TU experience that are now being applied to Second Avenue. Both of these projects require building tunnels and underground transit facilities in heavily traveled corridors of an urban city, in the vicinity of active business and commercial enterprises. To enhance the challenge, there are noise and vibration sensitive and historic urban receptors either over or along both the transit corridors. Column free Tren Urbano station caverns over18 m (60 ft.) wide were built in soft ground conditions within 3.6 m (12 ft.) of the surface under an aging heavy utility corridor, while NYCT tunnels with station structures stretching the limits of rock caverns to 34.8 m (100 ft.), were planned in rocky geology with the presence of shear and fault zones and some mixed face conditions. BACKGROUND During the early period of design/build experimentation, the speed with which the contract procurement packages could be put together enabled the owners to take advantage of the major efforts underway to rebuild the infrastructure that was suffering from post-World War II neglect. Use of design/build for new starts was unheard of and most of the projects were smaller in nature in order to allow the methodology to be tested. Development of functional design packages with the understanding that the D/B

Jan 1, 2005

By D. A. Keefe, O&apos

The electrowinning of beryllium from beryllium oxide (BeO) using a molten-salt electrolyte composed of 56 LiF-37 BeF2-7 BeO (mole-percent) was investigated. Anodes made of porous carbon were found to be superior in current-carrying capacity and gave a lower cell voltage than other types of anode material tested. When porous carbon anodes were used) the resultant increase in anode area prevented anode passivation. The cell voltage was 3.3 volts) and electrode current efficiencies of 50 to 70 percent were obtained. The electrodeposited beryllium was recovered as beryllium powder or was coalesced to metal beads by heating to 1,300° C.

Jan 1, 1970

By D. Settles, R. Rose, P. L. Dunn

"A new mineral sands operation is being developed in Georgia by Southern Ionics, Inc. (SII). Prevailing mineralogy and certain design constraints required detailed testing and circuit analysis to create a robust separation processes. The floating wet concentrator plant (WCP) and mineral separation plant (MSP) flow sheets were designed based on historical testing information and recent SII test campaigns on various composite feed samples. The flow sheets were finalized through rigorous process and orebody sequence modeling.The process uses traditional physical separation equipment; however a new MT spiral, the MG12, was selected for use on board the WCP for roughing duty. The MG12 spiral is a two-stage, twelve-turn spiral that has been proven to achieve very high recoveries of heavy minerals. The floating plant includes feed desliming operations, a central MT surge bin for optimum spiral circuit feed control and ancillary operations for concentrate and tailings handling. Scrubbed heavy mineral concentrate (HMC) is then transported to the MSP for concentration of the titanium and zirconium bearing mineral fractions.The testing, flowsheet development, and plant design will be described and explained, and a brief summary of the current project status will be given.IntroductionSouthern Ionics Inc. (SII) is a privately held chemical manufacturing company, founded in 1980 by Milton Sundbeck. SII focuses primarily on the sale of specialty and intermediate inorganic chemicals. Core markets include cement and refinery catalysts, molecular sieves, zeolites, pulp and paper, pharmaceuticals, TiO2 and water treatment. SII is built on the four cornerstones of service, quality, technology and delivery with all SII facilities ISO certified and key products used in potable water treatment certified to NSF standards. SII owns and operates its own transportation fleet and is focused on being a low cost producer, committed to safety and the environment."

Jan 1, 2015