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By W. K. Ting, A. Hasan

Mine stope is typically backfilled with cemented paste backfill, which provides a regional underground stability and also a reduction of aboveground tailings accumulation. During backfilling, a phenomenon known as arching occurs and affects the stress distribution of the cemented paste backfill. The change in temperature due to uncontrolled heat transfer from the surrounding rock mass and/or generation from hydration process complicates the stress distribution development of cemented paste backfill. This paper presents results of the investigation on the effects of hydration to cemented paste backfill behaviour when backfilled into a narrow wall model using uncemented paste backfill as controlled sample. The parameters considered include backfill type (cemented paste backfill vs uncemented paste backfill), curing temperature (30°C–60°C), and stress evolution during pouring, consolidation, and curing stages. Results show that uncemented paste backfill re-establishes arching effects more readily, with lower peak stresses and greater stress relaxation than cemented paste backfill, of which its behaviour is significantly influenced by hydration under elevated temperatures. The main outcome of this work is that hydration critically controls the stress-temperature response of cemented paste backfill, and the balance between hydration-driven strength gain and stress relaxation can be leveraged to optimise backfill mix design for safer and more efficient stope filling.

Jan 30, 2026

By K. S. Coley, M. A. Rhamdhani, G. A. Brooks

Interfacial phenomena in high temperature reactions such as between iron alloy and slag is well documented but not fully understood. It is believed that a gradient of oxygen concentration plays an important role to the occurrence of such phenomena. This article describes the results from the continuation of the study of interfacial phenomena between Fe-Al alloy droplets and CaO-SiO2-Al2O3 slag. Materials characterization techniques involving microscopic observations, depth profiling, bulk, point analysis and were carried out. The roles of oxygen as well as other factors that contribute to the interfacial phenomena were evaluated. The results and their implications to steelmaking will be discussed.

Jan 1, 2004

By Günther Staudinge

Aperam is a global player in producing of stainless, electrical and special steel qualities. The steelmaking plant in Timoteo Brasil is equipped with one AODconverter for stainless steel and one MRPL-converter for special steel production. After almost 20 years of operation Aperam decided to exchange the existing 80 t MRP-L converter by a new one including a new trunnion ring and a state of the art suspension system. Due to an optimized design the inner volume of the new converter could be increased which comes along with improved production. A special feature is a flange connection in the barrel section of the converter. This allowed to avoid any critical site welding and the time between shut down of the old and cold commissioning of the new converter could be done with 17 days only.

Aug 17, 2017

By J. Y. Hwang

Processing of fine mineral particles in a slurry is a difficult problem. Methods to make fine particles magnetic have been developed recently and may offer a solution to this problem. Particles of nonmagnetic materials can be selectively rendered magnetic through surface interactions with magnetic reagents. When adsorption occurs, the magnetic susceptibility of the material is increased. Magnetic enhancement at several orders of magnitude can be achieved. Selectivity of the adsorption can be controlled by the functional groups of magnetic reagents and various surface interaction mechanisms. This approach allows a new degree of freedom for the processing of fine mineral particles, even with conventional magnetic means. Separation of valuable minerals and filtration of slimes from tailing ponds and recirculated water are examples of the applications. Basic principles of this technology are discussed in this study.

Jan 1, 1992

THE plant is one of the usual type of Mond plants, and contains no new features worthy of comment. A brief description of the process, however, with a few remarks on the working of the plant, may prove of interest.Producer gas is made by passing a mixture of air and steam through incandescent carbon contained in a furnace called a producer, which, in the Mond type, is a cylindrical casing of steel plate, lined with firebrick, and fitted at the lower end with sloping fire-bars'. Coal crushed to an even size (about 2-in. gauge) is elevated to bunkers over the producers, from which it is fed into a measuring hopper on each producer.The hopper is a cast-iron cylinder fitted with a swing cover at the top and a bell valve at the bottom, worked by a lever and balance weight. When a charge of coal is run from the bunker into the hopper, the cover is closed, and the bell valve is lowered, allowing the coal contents to drop into the producer. Thus no gas can escape from, or air be admitted to, the producer during the process of charging. The hopper discharges its coal through a steel pipe-shaped container called the bell, which projects about 9 in. through the roof of the producer. The function of the bell is to spread the coal evenly over the fire, and supply coal to any portion of the fire as it settles.

Jan 1, 1918

By BURCU NILGUN CETINER, Serdar Aktas

Antimony has been used extensively in industry and in everyday life since the 19th century, and antimony sulfides have been known since around 4,000 B.C. Antimony’s most significant applications are as a flame retardant in the manufacture of electronics and textiles, as a catalyst for plastic fabrication, and as paint pigment and fining agent in glassware, opacifier in ceramics and an alloying element in ammunition and battery manufacturing plants. It is also used in vehicle brakes and tires. Brake pads contain stibnite (Sb), the sulfide compound of antimony. In particular, stibnite is used in automobiles as a lubricant, vibration reducer and friction stability improver. Anthropogenic activities are the primary source of antimony in the atmosphere [1,2]. Annual global consumption of antimony has increased to more than 1.4 × 105 t, and China is the most significant producer [2].

By George A. Guess

THE increasing demand for greater speed and more accuracy, in making daily assays of ores and products from mills treating material containing but very small quantities of lead and copper, has caused the older analytical methods to be supplanted by new ones devised to meet the needs of modern work. For " control " work in copper analyses, I had, previous to the present equipment, introduced in my laboratory the ordinary electrolytic method, using hollow cylindrical electrodes, and with these I began a series of experiments in determining the lead-content of daily mill-samples and controls. The results, proving accurate and satisfactory, I then devised, with Mr. H. E. T. Haultain, a cheaper electrode than the ordinary jacket electrode, which costs from $15 to $20,-the expense of the older form making the installation of many units very costly. The form of cathode finally adopted as the most satisfactory, shown in Fig. 1, is cut from 0.001-in. platinum foil. It is 12.5 cm. long, and is divided into a blade 4 cm. wide and 6.25 cm. long, and a tongue 0.7 cm. wide and 6.25 long, the immersion area being 50 sq. cm. and weight 1.5 grams. The blade is first sand-blasted and then corrugated lengthwise, in order to impart the necessary rigidity. Strips of platinum foil 0.001 in. thick, 12.5 cm. long and 0.5 cm. wide, having a median corrugation, form the anodes. Three electrodes are used in each cell, one anode in the middle and one cathode oil each side of the anode. These electrodes are connected to slotted alumi¬num terminals, in which they are held by contact pressure. The terminals are -in. rods, projecting 2 in. horizontally in front of the wall of the cabinet.; at the back the middle electrode (anode) is connected with one pole of the current, and the two outer ones (cathodes) with the other pole.

Nov 1, 1905

By Tailoka F.

Various metallurgical residues from iron and steel making processes have been treated by chlorination in excess air with hydrogen chloride gas generated from the combustion of scrap polyvinyl chloride (PVC). The residues include dust from both the electric arc and blast &maces, hydrocyclone overflow, zinc - lead blast furnace slags and dust rich in zinc and copper from copper refining. Chlorination is achieved either directly by mixing the residues with scrap PVC or indirectly in a two furnace system. In the latter, scrap PVC is combusted between 523 and 573 K in a horizontal furnace and the resulting gases are then reacted with metallurgical residues in a vertical furnace at 1166 to 1329 K. Gas chromatography, thermogravimetric measurements, XRD and AAS have been utilised to study the reactions. The recovery of non ferrous metals is as high as 80 to 90 % and only a negligible amount of iron is carried over. The optimum temperature for combustion is between 518 and 573 K. Above 600 K, the evolution of HCI is so fast that sufficient chlorination is not achieved. Analysis showed that no dioxins were present in the gases, the residues or the chlorides.

Jan 1, 1997

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1940 are available at Institute headquarters, unless otherwise noted. They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS. TECHNICAL PUBLICATIONS in Classes A-Metal Mining, B-Milling and Concen-tration, H-Industrial Minerals, and I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Technical Publications in Classes C-Iron and Steel Division, D-Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. TECHNICAL PUBLICATIONS in Class G-Petroleum Division are distributed in PETRO-LEUM TECHNOLOGY, which was issued quarterly in 1940 but will be issued every other month in 1941. TECHNICAL PUBLICATIONS in Classes F-Coal Division, J-Mineral Industry Education Division, K-Mining Administration, and L-Geophysical Methods of Exploration are issued as separate pamphlets. An Institute member is entitled to one copy of any TECHNICAL PUBLICATION or CONTRIBUTION. Copies of TECHNICAL PUBLICATIONS listed have been mailed to members of the Institute accord-ing to their registration by classes. CONTRIBUTIONS and other TECHNICAL PUBLICA-TIONS will be sent upon request. A member may purchase an additional copy of a TECHNICAL PUBLICATION or a CONTRIBUTION at one cent a page; minimum charge, 25¢. Nonmembers may purchase any CONTRIBUTION or a TECHNICAL PUBLICATION of the F, J, K, or L classes at the same rate, but the nonmember price per copy for METALS TECHNOLOGY, MINING TECHNOLOGY or PETROLEUM TECHNOLOGY is $1.25 domestic, $1.35 foreign countries. TECHNICAL PUBLICATIONS (separate pamphlet form), $2 per annum domestic, $2.50 foreign. METALS TECHNOLOGY, $7 per annum domestic, $7.80 foreign (Iron and Steel Division and Institute of Metals Division ferrous and nonferrous papers). MINING TECHNOLOGY, $6 per annum domestic, $6.60 foreign (metal mining, milling and concentration, Industrial Minerals Divi-sion, and mining geology papers.) PETROLEUM TECHNOLOGY, $6 per annum domestic, $6.60 foreign. Bound volumes have been mailed to members that have requested them, and MINING and METALLURGY is mailed each month. A member is entitled to one volume a year on his membership and he may purchase for $2.50 one copy of a volume not already received; additional copies of the same volume, $5. Nonmembers may pur-chase the volumes listed, at $5 each, plus 60 cents for Canadian or foreign postage. Extra single copies of MINING AND METALLURGY, 25¢ current issue, back numbers 50¢ each to members; to nonmembers 506 current issue and $1 each, back issues. Subscription price to nonmembers and to members for extra copies, $3 per annum domestic, $4.00 foreign.

Jan 1, 1940

By Gerald T. Homce, Michael R. Yenchek, H. Kenneth Sacks, James C. Cawley

Accidents occur when least expected, from sources that we rarely anticipate and with outcomes that can vary greatly. Anyone who has ever been involved in an automobile accident knows, the transition from driving comfortably and safely down a highway to being involved in a potentially life-threatening situation can occur in a heartbeat. Accidents on the job are no different. The mining industry has a relatively small number of electrical injuries, compared to industries such as construction or agriculture, due to the small total employment in mining. Mining does, however, have one of the highest occupational electrocution rates of any U.S. industry, at 2.8 for every 100,000 workers per year. This is approximately four times the average for all industries. Data from the Mine Safety and Health Administration (MSHA) shows that 75 electrical fatalities occurred in the mining industry between 1990 and 1999. Of these, at least 17% involved high-reaching mobile equipment that contacted overhead power lines.

By AJ LYNCH

Broken Hill metallurgists have been responsible for some of the most important developments in mineral processing technology. These occurred mainly in two periods, 1902 - 15 and 1955 - 70. Mineral flotation was developed as an industrial process during the first period and this happened in two stages, the recovery of zinc minerals from the tailings dump accumulated during the gravity concentration of the oxidised ores and the selective recovery of galena and marmatite during flotation of the primary ores. During the second period fast accurate analytical procedures were developed to provide rapid assessment of process performance, and new means of controlling the process were devised which improved throughputs, grades and recoveries. These technological successes were due to the skills of the metallurgists and the commitment of the companies. They brought large financial returns. They were achieved under difficult circumstance. There are important lessons to be learnt from these successes.

Jan 1, 1992

By F. G. BREYER

ZINC metallurgists continue to follow with keen interest reports of successful results from the continuous retort plants at Palmerton, Pa., and Meadowbrook. W. Va. The new process had already demonstrated its ability to reduce the lead content of the metal and to effect savings in labor and fuel. The past year has shown that the retorts themselves can he built to last long enough so that the retort cost per ton of metal is lower than in past practice with small horizontal re- torts. A number of the latest type of retorts are reported to have been in continuous operation for over 18 months without a failure and are said to be still in good condition. This seems a complete answer to the last question which remained before continuous zinc smelting could he pronounced commercially practicable.

Jan 1, 1932

By Louis A. Panek

The practice of roof bolting, now recognized as an effective method of support, is based largely on rule of thumb. Among the various applications of bolting, the support of stratified mine roof is by far the most common. The general principles relating to this type of reinforcement are presented in two companion reports; the first describes the function of the bolts, the bolting pattern, and the behavior of bolted roof (1), 2/ and the second describes the design of the models and the theory of the experimental method (2). This report presents a rational method for designing systems of vertical bolts to reinforce horizontally bedded mine roof, developed from model tests. The structure treated herein may be described as follows: The immediate roof, consisting of beds of like material and equal thickness with no bond between them, is reinforced by vertical bolts installed in straight lines across the opening; the case of suspension is excluded because the bolts are assumed not to extend above the immediate roof. The assumption is made that the behavior of the lowest bed approximates that of a rectangular plate clamped along two opposite sides (the ribs). These specifications represent approximately the roof conditions encountered in mining bedded deposits of all kinds - coal, potash, iron ore, etc. Thus, for the design of a roof-bolting system a quantitative solution to the following problem is required: For a roof composed of beds of given thickness and physical properties, how does the support depend upon the length, spacing, and tightness of the bolts?

Jan 1, 1956

By N. Parnian

"Carryover of caustic soda (NaOH) in the steam path caused catastrophic failure of superheater 304H stainless steel tubes in a steam generator and led to an unexpected shutdown after just five months of continuous service of petrochemical following the start of production. The cause of the failure was studied, with a focus on the formation of sigma phase in the weld joint and effect of caustic embrittlement on stress corrosion cracking (SCC). The cracks were examined at the seam weld, heat affected zone (HAZ), and Ubend areas. Hardness was measured for the base metal, HAZ, and weld metal, and microstructures were examined using optical microscopy and scanning electron microscopy (SEM). Crack initiation is attributed to gouging on the precipitated carbide at the HAZ and also the formation of sigma phase in the weld metal, as shown by energy dispersive X-ray (EDX) analysis. In addition, cracking was propagated by caustic embrittlement because of residual stresses and hammering. Finally, the characteristic feature of fracture was illustrated by SEM fractography, and consists mostly of intergranular SCC and some quasicleavage transgranular. INTRODUCTIONThree key factors are needed for the initiation and propagation of intergranular stress corrosion cracking (IGSCC): a susceptible material, a corrosive environment, and sufficient stress. Although austenitic stainless steels are susceptible to sensitization and IGSCC, they are widely used in boiler and superheater tubes because of their high corrosion resistance, high oxidation resistance, acceptable mechanical characteristics at elevated temperatures, and low cost.Sodium hydroxide is injected to neutralize acidic constituents in the steam path, but caustic can concentrate in boiler tubes and attack the surface metal (known as gouging) even traces of caustic in the steam can deposit on surfaces and cause local concentrations of several percent (ASM handbook, 1992). Not only sensitized grains but also sigma phase formed in the weld metal can initiate caustic cracking. In this research, the cause of the failure of 304H stainless steel superheater tubes in a methanol petrochemical plant in Iran was studied with a focus on the effects of caustic embrittlement on IGSCC."

Jan 1, 2012

The 29th annual American Mining Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Star Pass Resort, Tucson, AZ on Saturday, Dec. 3, 2011. Each year, one living inductee, two recipients of Medals of Merit, and up to five honorees from mining history are chosen by the MFSW for their outstanding contributions to the mining industry. Chilean Minister of Public Works and former Minister of Mining, Laurence Golborne Riveros will be the guest of honor, featured speaker and inductee into the American Mining Hall of Fame. Golborne Riveros was instrumental in managing the rescue of the 33 Chilean miners in October 2010 and in the coordination/management of the ?townsite? for family members, rescue support and the media. His engineering background and executive management skills made him ideally suited to assist in both a technical and managerial role in this emergency.

Jan 1, 2011

By Jan Kvinge, Aina Opsal Bakke, Yanjun Li, Jan-Ove Løland, Svein Jørgensen

"Compound casting is a very attractive approach to reduce the weight of components for some specific applications while keep both the functional and the mechanical property requirements. In this work, Al-7Si-Mg alloy /copper compound castings were produced through a low pressure die casting process. To reduce the oxide present in the interface, flux coating of the copper pipes was tested. The interface layer formed between the two alloys was investigated using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Vickers Micro-hardness was also measured across the interface. Results showed that the flux coating prevented the formation of the metallic bond between copper and aluminum. Instead, high concentrations of potassium, magnesium and fluoride, coinciding with formation of KMgF3 and MgF2, were detected in the interface. In the castings without surface treatment, a continuous metallurgical bond was achieved. In the bond layer, various Al-Cu intermetallic phases have been detected. In addition, formation of primary silicon particles in the reaction layer was observed in all castings. The mechanism for the formation of the intermetallic phases and the strength of the interface layer have been discussed.INTRODUCTION Recent development in the automotive industry has focused on producing lightweight components, which can reduce CO2 emission and increase the efficiency. Often, one material alone is not able to meet the requirements for a specific use. The need for lightweight bimetallic components has therefore increased. Aluminum-copper bimetallic components can be used in wires and bus bars where conductivity is an important factor (Lee, Bang, & Jung, 2005). Compared to Al-Cu alloys, Al-Cu bimetallic components can reduce both weight and cost without reducing electrical and thermal conductivity (Sheng, Yang, Xi, Lai, & Ye, 2011). A challenge is, however, that aluminum and copper have high affinity to each other, especially at elevated temperatures. This causes formation of brittle intermetallic phases with high electric resistance (Liu, Wang, Sui, Wang, & Wenjiang, 2016). In addition, both metals are subjected to oxide formation on the surface. Copper is especially exposed to oxidation at elevated temperatures (Pinnel, Tompkins, & Heath, 1979), while a thermodynamically stable oxide layer will spontaneously form on the aluminum surface (Papis, Loeffler, & Uggowitzer, 2009). Oxides are known to be passive substrates, which will reduce wettability and will thus prevent the formation of metallic bonding between aluminum and copper (Papis, Hallstedt, Löffler, & Uggowitzer, 2008)."

Jan 1, 2018

Breakwater Resources Ltd is a Canadian base metals producer with Cu-Pb-Zn operations in Canada, Honduras, and Chile. Two of its operations contain economical gold levels which are recovered in both gravity and flotation concentrates. The gold payable terms in zinc concentrate are poor when compared to gold concentrates or copper concentrates and various flow sheets have been evaluated by Breakwater staff to maximise gold reporting in higher value products. The Myra Falls mine in British Columbia recovers coarse gold in the grinding circuit, part of which is upgraded and sold as a gravity-gold concentrate with the balance being directed to the copper concentrate. A sampling survey showed that there was potential gravity-recoverable gold in the copper regrind circuit. Installing a gravity concentrator in the copper regrind circuit increased the gold grade and recovery in the higher revenue copper concentrate and reduced the quantity reporting to the less well paid zinc concentrate. The El Toqui Mine in southern Chile has distinct high-and low-gold orebodies which are campaigned separately through the flotation plant. The high gold zone yields both a gravity concentrate and an unusual gold flotation concentrate. The gravity concentrate undergoes intensive cyanidation and electrowinning on-site to produce dore, while the fl otation concentrate is sold to gold producers. The zinc concentrate contains signifi cant gold values. The paper describes efforts over the past few years to improve gold returns at Breakwater's operations and highlights the different approaches dictated by the mineralogy of the gold occurrences at these two operations.

Aug 1, 2010

By Andrew Torok

Activated bleaching clays, so called because of their ability to remove color bodies from bleach fats and oils, are produced from clays of bentonitic origin. Activation is achieved by subjecting these clays to physical or chemical alteration to increase selective sorption capacities (1) . The future of activated bleaching clays depends upon the ability of producers to recognize the new areas of applications which are arising, and their skill in developing sophisticated active clays to meet new and stringent requirements. The major portion of activated bentonites are produced for decolorization of oils. New techniques of activation will improve these clays for broader spectrum use. General properties expected to result from present activation methods are: 1. Modification of hydrophobic-hydrophilic properties and increased available surface area in non-aqueous systems, thereby improving sorption capacity and ability to remove color bodies from oils. The following additional properties will be expected from future activated clays: 2. High purity of the active clay with interfering impurities totally removed. 3. Increased selective sorption capacity in aqueous systems. 4. Selective chemical reactivity, such as oxidation or hydrolysis. This property is required for removing

Jan 1, 1971

By C. Bester, G. M. Rohde

A major challenge in the mining sector is the responsible management and efficient storage of mine residue. Over recent years numerous tailings dams have experienced unintended spills and failures, with severe consequences for the mining industry, the environment, local communities, and the regional economy. The fourth industrial revolution (4IR) is impacting society due to increased interconnectivity, processing speed, and automated technologies. This paper explores whether 4IR technologies have the potential to mitigate risks associated with tailings dams. Experts in the field of tailings dam operational management were surveyed to determine their view on the risks associated with tailings dams and the potential of 4IR technologies to mitigate these risks. The survey found that a majority of experts believe that certain 4IR technologies have the potential to reduce the risks associated with tailings dam failures.

May 27, 2025

By Erle C. Donaldson

The pendant drop interfacial tensiometer is being used to study interfacial phenomena that influence the production of crude oil. A description of the instrument showing the modification of the cell and cell holder is presented. The modified cell and cell holder allow formation of a precise and reproducible drop size, and the image of the drop is easily alined and focused. Interfacial tension measurements and observations of film formation can be conducted at various temperatures with the jacketed cell.

Jan 1, 1967