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By Farzaneh Abedini, Narain Hariharan, Lucas C. McFarlane, Nikolas A. Romaniuk, Tiffany Thayne

The use of dewatered mine tailings as backfill material (commonly referred to as ‘paste’ backfill), is the most practiced form of backfill in Canada providing significant environmental benefits by reducing the size of external tailings facilities and improved economics through enhanced resource recovery. Paste backfill operations reuse filtered mine tailings with a cementitious binder and water to create a slurry that is hydraulically transported to refill underground stopes, later forming a structural network of cemented tailings in the mine stopes. Unlike typical structural applications that utilize General Use (GU) Portland cement; modern paste backfill operations maximize strength performance by blending Portland cement with ground granulated blast furnace slag (GGBFS) or other supplementary cementitious materials (SCMs). GGBFS and other SCMs offer key performance benefits and carbon reductions; however, the availability of these SCMs is rapidly dwindling in today’s carbon-constrained economy. This paper examines the development of an alternative binder system that provides similar performance and carbon reduction to that of GGBFS for mine backfill operations. The binder utilizes the chemical reaction between a reactive source of aluminosilicates and available calcium from calcium oxide or calcium hydroxide to replace between 50 to 100% of GGBFS. The performance of the binder is examined with insights into the hydration mechanisms that generate mechanical strength in the cemented paste network. Paste backfill slurries require precise engineering to create a material that maintains flowability during pipeline transport and generates enough strength to meet operational targets once placed in the stopes. Engineering of such slurries requires large amounts of water to be added to the binder-tailings matrix, far exceeding the typical water to binder ratios used in concrete mix designs. This characteristic of paste backfill warrants great emphasis on understanding the hydration mechanisms of the binder used in the paste backfill system. GU cement is typically composed of 50-70% tricalcium silicate and 15-30% dicalcium silicate.  The hydration mechanisms of these compounds consume 4 to 6 units of water to mineralize into calcium silicate hydrate cemented phases that result in compressive strength development. Cementitious aluminate and aluminosilicate phases make up 5-20% of GU cement and aid in secondary performance characteristics such as set time. Certain calcium aluminate hydrate phases such as monocarboaluminate and ettringite mineralize 10 to 32 units of water into their crystalline structure. Hydration products such as ettringite are traditionally avoided in construction applications due to their propensity for volumetric expansion after cement setting, leading to micro-fissures and subsequent strength degradation (known as ‘sulfate attack’). This paper proposes that such hydration products benefit the strength development in paste backfill slurries with the aforementioned characteristics due to their greater potential to mineralize free water. The newly developed calcium aluminosilicate binder is designed to replace 50-100% GGBFS or other SCMs used in paste backfill systems and meet operational strength requirements by providing exceptional hydration characteristics through cementitious reactions. Additionally, the aluminosilicates used have a minimal carbon footprint and a secure supply outlook, thereby allowing mine operators access to a low-carbon binder option throughout the mine’s lifespan.

May 4, 2025

By C Samuelsson, Q Shu, A Lennartsson, F Gyakwaa, A Andersson, J Isaksson

The physico-chemical property, viscosity, is essential for pyrometallurgical processes and influences the settling rate of valuable metal droplets in slag, affecting the metal recovery. The copper slag from smelting furnaces typically contains between 1 and 2 wt per cent Cu, which equals to or is higher than in most sulfidic copper ores mined today, meaning the slag is a valuable resource for copper extraction. A low viscosity is desirable for slag-cleaning through a settling furnace where entrained droplets settle under gravity. One approach to control the viscosity is through the slag composition. The literature has limited data on the correlation between viscosity, slag structure, and optical basicity of iron silicate slag with FeO/SiO2, CaO, and Al2O3 as factors. Therefore, the present study evaluated the influence of these factors on viscosity and correlations with slag structure and optical basicity. The FeO/SiO2 ratio (at%/at%) and the CaO and Al2O3 content were altered in two levels, resulting in a two-level full factorial design with three factors. The study was done by synthesising FeO–SiO2–Al2O3–CaO–MgO–Cr2O3 melts, followed by water granulation. The melt structure of the samples was analysed with the help of Raman Spectroscopy. The viscosity was then estimated with a high-temperature rheometer using a Mo spindle and crucible. The results showed a correlation between the optical basicity, FeO/SiO2 ratio, and viscosity, where a high optical basicity and FeO/SiO2 ratio were beneficial for achieving a low melt viscosity.

Jun 19, 2024

By Sandeep Pattnaik

Spring stiffness of soil and rock at different depth is often required for a pile structural model. If the pile is rested in multiple layers of soil, then it is rather more complex to simulate the soil in a structural model. The spring stiffness will vary based on density of soil strata over the depth. When a pile is socketed in weathered rock followed by a soil layer, a sudden change in subgrade modulus can influence the pile deflection drastically. Determination of soil spring and simulation of the pile in this condition required correct interpretation of subgrade modulus. The conventional approach of pile spring calculation underestimates the spring stiffness by ignoring underlaying stiffer layers. A finite difference method (FDM) of analysis can reasonably estimate the p-y of soil / rock based on subgrade modulus of each layer. However, the transition between the layers can be better simulated as per the deflection pattern of the pile. The lateral deflection of the pile is mainly dependent on the stiffness of soil layer surrounded by the pile. Generally, the lateral influence of a pile varies from 4D to 6D depending on the soil type. Therefore, soil spring stiffness around the pile would require special attention of a Geotechnical engineer to avoid uncertainty in the prediction of pile behaviour. In this paper, emphasis has been given to develop an approach for pile spring stiffness design. A standard software program LPile has been used to develop p-y curves of soil and rock layers at different depths and then converted to soil/ rock springs over the depth. Modulus of Subgrade Reaction as given in IS 2911 (Part2) was also used to correlate the spring value for different type of soil. Obtained analytical results were compared with full scale field trial for lateral deflection of pile. A good agreement between these two approaches has been established. The effect of soil structure interaction in the structural model shall be simulated by assigning an equivalent vertical and horizontal soil spring, which is developed by Winkler’s soil spring approach. A simplified design principle for calculating the pile spring is discussed in this paper. This approach has been extensively used in Mumbai metro elevated line pile design.

Nov 1, 2022

By Ralph H. Whaite

The Bureau of Mines program for microfilming maps of abandoned mines in the Pennsylvania anthracite region is described. A catalog of the maps that have been microfilmed in the Eastern Middle anthracite field--the first area to be covered in the program--is presented. Additional catalogs will be published as significant mining areas are completed.

Jan 1, 1965

By Ralph H. Whaite

The Bureau of Mines program for microfilming maps of abandoned mines in the Pennsylvania anthracite region is described. A catalog of the maps that have been microfilmed in the Eastern Middle anthracite field--the first area to be covered in the program--is presented. Additional catalogs will be published as significant mining areas are completed.

Jan 1, 1965

By Justin R. Patts, Andrew B. Cecala, A. KYLE LOUK, Emily J. Haas

The National Institute for Occupational Safety and Health (NIOSH) and the former U.S. Bureau ofMines (USBM) have given a significant effort over the past four decades in researching and developing engineering controls and interventions to reduce mine workers’ dust exposures during the bagging and palletizing of industrial minerals. Workers performing manual bagging and palletizing of 50- to 100-pound bags typically have some of the highest dust exposures of all workers at mining and mineral processing operations. This paper will provide an overview of available dust control technologies for bagging operations and present the findings of a recent case study that was conducted at four different industrial sand operations to identify the current types of bagging and palletizing technologies being used and to evaluate their effectiveness in reducing workers’ exposures to respirable crystalline silica dust. An evaluation will also be performed to determine if further reductions in respirable dust levels can be achieved by incorporating additional modifications or improvements into the existing technology.

Apr 3, 2020

By M. K. Mohan

Lead recovery from process solutions contributes not only to the conservation of resources but also clean environment. Zeolites are natural aluminosilicates, which finds applications as catalysts and in wastewater treatment. In the present investigation, studies were taken up on the processing of Pb from process solutions by zeolites. Effects of pH of the solution, time and type of zeolite viz. chabazite, mordenite, erionite and clinoptilolite on the removal of Pb from solutions was investigated. Rate of sorption was found to depend on the pH of the solution and about 99 pct. recovery was observed at pH 6. Optimal conditions were established for the maximum recovery of lead from process solutions. Possible sorption mechanisms were proposed. The calculated adsorption constants calculated from Langmuir and Freundlich equations showed that the adsorption of lead on chabazite was strong.

Jan 1, 1999

By Glenn Buchana

El presente texto señala algunos aspectos técnicos y comerciales del dragado del depósito fluvial. Para ello, es necesario conocer el origen y desarrollo del depósito fluvial. El depósito fluvial es una masa de grava superficial, la cual es producto del desmoronamiento y erosión de rocas sólidas que contienen partículas o pepitas de oro, diamante, estaño, platino u otros minerales valiosos que proceden de las rocas o de las vetas. Entre los tipos de depósitos aluviales tenemos: depósitos aislados pequeños y poco profundos, los depósitos de mediana profundidad, depósitos profundos y los marinos. La explotación se realiza a través de tres sistemas: draga cortadora de succión, la dragalínea de cangilones y la planta de tratamiento flotante.

Nov 1, 1979

By E. T. de Groot, D. L. Verhelst

With the successful start-up of Cominco's new KIVCET smelter, the final key component is now in place for Trail Operations to operate efficiently as a modern integrated zinc-lead facility. Unique metallurgical, operational, planning and management issues apply to this operation. Along with presenting the current flowsheet for Trail Operations, this paper discusses issues such as the impact of recycles, operational re-stabilization following significant process changes, plant operation with just-in-time inventories, real-time process optimization, and management philosophy.

Jan 1, 2000

"The most common agglomeration technique in iron and steelmaking is sintering, which requires the use of iron ore/concentrate mixtures, limestone and dolomite as fluxes and coke as fuel in order to produce the required melt at high temperature to cause agglomeration of the particles. Sinter feed blends containing high proportions of magnetite concentrate are difficult to granulate and to produce granules of high permeability, and sufficiently robust quasi-particles for successful sintering operations. Since the granulation of iron ore sinter feed requires no use of a binder, the added fluxes play a vital role in holding the granule particles together until they sinter. The fluxes also help to improve the granule quality and control slag composition in the blast furnace. It is well-known that the particle size distribution of the fluxes affects the granulation effectiveness and green bed permeability which determine the productivity, physical and metallurgical properties of the granules and sinter. Hence it is necessary to understand the role of flux particle size on granule properties so as to improve the granulation of iron ore sinter feed blends containing high magnetite concentrate. In this study, laboratory granulation experiments have been carried out on iron ore sinter feed blends containing high proportions of magnetite concentrate at different addition levels of limestone and dolomite mean particle sizes, to understand the influence of limestone and dolomite particle sizes on granulation rate processes and granule properties.INTRODUCTION Increases in iron ore production to meet the global demand for iron and steel products has led to the depletion of high grade iron ores and thus the current utilisation of low grade iron ore fines and concentrates. However, sinter, pellets and the lump are the required feed types used in the blast furnace. The high basicity sinter is the main iron bearing feed accounting for 70-85% in the blast furnace due to its good metallurgical and mechanical properties that allow high productivity, efficient processes and low production cost (Adam et al., 2017)."

Jan 1, 2018

By B. Winterberg, C. Lewis, M. Starkel, C. Johnson

Non-electric systems, specifically shock tube, have become the pyrotechnic detonator of choice over electric due to their safety regarding accidental initiation from stray radio signals. Typically, the best practice when hooking up shock tube systems is to have direct contact to ensure initiation. When gaps are introduced to the explosives chain, there is potential for detonation to come to a halt. It is understood that direct coupling is required between the various elements in the explosive chain to ensure detonation. This holds true whether tying in non-electric detonators, loading holes in a mining related blast, or priming a block of C-4. Poor contact and gaps in the explosives chain can lead to detonators firing out sequence, leading to increased vibration, air overpressure, and other undesirable blast results. Furthering work conducted in previous experimentation, a new study was conducted at the Missouri University of Science and Technology’s Experimental Mine in Rolla, Missouri to observe the initiation potential of an air gap and fragmentation on non-electric shock tube. A series of small test blasts were conducted using 50 grain detonating cord and fragments from a blasting cap to initiate a non-electric shock tube across an air gap of varying distances. The data collected in the high-speed imagery was used to analyze the velocity of the pressure fronts and blasting cap fragments used to initiate non-electric shock tubes across an air gap. It was found that the shock tube was sensitive to 50 grain det cord at a 5cm (1.97in) distance while parallel and 10cm (3.94in) when perpendicular as well as sensitive to frag from the electric cap out to 2.4m (7.87ft).

Jan 1, 2024

By D Craw, P V. Angus

Gold mineralisation at Macraes occurs as late quartz-carbonate veins within a body of sheared and hydrothermally altered Otago Schist, the Intrashear Schist. The alteration is characterised by the presence of rutile and the absence of epidote and titanite, indicative of an alteration fluid containing >10 mol per cent CO2. In areas of high strain, a fabric of black microshears develops, gradational to mylonitic cataclasite in the high strain zone adjacent to the hanging wall of the duplex shear zone. The microshears contain hydrothermal graphite, inferred to have been deposited from a methane-rich fluid. The mylonitic cataclasite is characterised by abundant pyrite, the absence of albite and extreme grain size reduction. Gold recovery in the CIL processing plant at Macraes can drop to 50 per cent or lower for some unfavourable ore types. Preg-robbing by a component in the ore, possibly graphite, was suspected as the cause. Mylonitic cataclasite was identified as the lithology responsible for the poor recoveries, with the capacity to bind about 30 ppm of gold in the leach tanks. A program of detailed geochemistry and quantitative grain-size measurement using Coulter analysis was undertaken to identify specific mineralogical factors associated with preg-robbing. The results indicate that pyrite, graphite, and extreme grain-size reduction are the factors associated with highly preg-robbing ores at Macraes. The evolution of the mylonitic cataclasite is accompanied by strong potassium enrichment, as muscovite, and depletion in sodium as albite is removed. This suggests that a simple powder XRD ratio of the albite to illite peaks would suffice to distinguish the preg-robbing ore for grade-control purposes.

Jan 1, 1999

By Clinton H. Crane

IN October, 1925, J. R. Finlay delivered an address entitled, "The Future Price of Lead." Lead was then selling at 8.85c. and Mr. Finlay and most of the rest of us were concerned about the shortage. Now, a little more than six years after, lead is selling for 3.55c., and nobody is worrying about the difficulty of getting plenty of it. For 1931 the U. S. G. S. reports United States produc¬tion as 390,000 tons of recoverable lead in ore. Our estimate is slightly higher than this; nearer 400,000 tons. This is the smallest production since 1911 and 1912, but in spite of this, stocks for the year-have increased nearly 50,000 tons. Our estimate for the production outside the United States is 1,120,000 tons, or more than double the production of either 1920 or 1921, and 30 per cent more than in 1913. Stocks abroad probably have not increased more than stocks in the United States. In other words, foreign consumption is double what it was in 1.920-21, whereas domestic consumption is substantially less. It looks as if Mr. Krueger, president of the Swedish match trust, was right when he said that "This country had better stop worrying about Europe and think a little bit more about its own affairs."

Jan 1, 1932

By Oleg G. Tovmachenko

We have studied optical properties of fluorescent nanoparticles. These particles consist of a metal (gold/silver) core, an empty and a dye labelled silica shells. The different dye molecules with moderate quantum yields (about 0.3) has been used. Almost all of types of nanoparticles show fluorescence enhancement. This enhancement is strongly dependent on the degree of the overlap between the surface plasmon band of the metal and the absorption/emission band of the dye molecules. The results are interpreted in terms of competition between local field enhancement and quenching of fluorescence by the metal surface.

Oct 1, 2003

By W. E. Coates

The social ecology of surface mining in urban areas is illustrated by a case study of a recent application for the opening of a new gravel pit in the city of Guelph, including the design of a progressive extraction-rehabilitation sequence for the property, investigation of the ecological impact of the proposed operation, history of the application procedure for a zoning change and the relationship of the operating plan to provincial legislation controlling surface mining.

Jan 1, 1972

By Richard Akerman, Frederick Prime Jr

[THE attention now being paid both in this country and Europe the greatest economy in the working of the blast furnace, and the eagerness with which all thoughtful men in the iron business look for any new information which will tend to throw light on this subject, is a quite sufficient excuse for presenting this paper to the American Institute of Mining Engineers.] I. It must be borne in mind that when two bodies unite to form a chemical compound, heat is almost always evolved. In order to

By George S. Austin

Adobe, dried mud bricks, have been used since before historic time in the construction of dwellings. Building materials are normally evaluated for thermal performance based on measurements known as R- and U-values. The R-value is an indicator of the ability of a wall to insulate effectively and the higher the R-value, the better it is as an insulating material. The U-value, or value of conductance, is the reciprocal of the R-value and reflects the rate at which heat is conducted through a material. But the "heat capacity of the wall" must also be considered. This measures the length of time that passes before a steady state of heat flow is achieved. The effective U-value measures both the resistance to the transfer of heat and the capacity to hold heat. These latter value make adobe a far more interesting as a modern building material that was formerly recognized.

Jan 1, 1983

By J .. F. Brownrigg

In the mining method used at O'Okiep Copper Company (OCC), vertical crater retreat, the prime requirement for the fill is that it should be sufficiently strong to be free-standing to a height of 150 m. Other requirements are minimal decant and drainage water, and high pulp density to allow large tonnages to be placed quickly and alleviate transport problems. The excessively high cost of cement precluded the use of a cement-based fill, and after three years of extensive investigations a backfill based on the smelter slag was produced. Currently a fill with a uniaxial compressive strength of greater than 1 000 kPa after one month is being produced. This is in excess of the design specification of 850 kPa after 2 - 3 months. The research and development which went into the slagfill is briefly covered; the production of the fill from the various raw materials is described; and the design and control systems of the backfill plant, the reticulation system and its monitoring are examined. Finally, the implications of this high- quality fill for the mining programme are assessed.

Jan 1, 1988

By W. S. Ayres

I. INTRODUCTION. THIS cavern was discovered Oct. 22, 1904, by Mr. Charles H. Deutschman, in company with whom I made, May 29 to June 3, 1905, at the request of Mr. Howard Douglas, Superintendent of the Canadian National Parks, the first exploration of it for the Canadian government. The results were stated in a paper, orally presented, with lantern-views from my photographs, at the British Columbia Meeting of the Institute, Victoria,, B. C., July 5, 1905.* The present paper embodies also the results of a second examination, made Oct. 25 to 29, 1905. The accompanying map, Fig. 1, will serve as a guide to the following description. II. LOCATION. The cavern is situated at snow-line, at the head-waters of Cougar creek, on the west slopes of the Selkirks, about 2 miles north from Ross Peak water-tank, and 5.5 miles west from Glacier House, on the main line of the Canadian Pacific Railway. It was then reached by an arduous climb from the water-tank, up the ravine of Cougar creek, for 8,000 ft. (2,000 ft. of altitude) over rock- and snow-slides, and through a thick tangle of alders. But an easy and very picturesque trail has, during the past summer, been opened by the government from Glacier House. Figs. 2, 3 and 4 represent views, not heretofore published, of the grand scenery of this region, so rapidly becoming the-object of attraction to thousands of tourists from all parts of the world. These views, as well as those shown in. Figs. 5, 6, 7, 8

Jan 1, 1907

By C. M. McKinney

Bureau of Mines routine crude-oil analyses of 42 samples from 37 fields in the major producing areas in Mexico are presented in this report. Table 1 includes information on the source and general characteristics of each sample. Table 2 gives a summary of analytical and computed data. A map (fig. 1) shows approximately where the samples were obtained. ACKNOWLEDGMENTS Grateful acknowledgment is made to Alfonso Barnetche, manager of production, and Ing. Francisco Inguanzo, assistant manager of production, both of Petroleos Mexicanos, who supplied the crude-oil samples and furnished information concerning their sources.

Jan 1, 1960