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By MOHAMED WAEL, ANASTASIA GOEVA, ABDULAZIZ TAWFEEQI, IHTISHAM TARIQ, S. M. ZAKIR HOSSAIN, NIAZ ALI KHAN, MUHAMMAD FAISAL IRFAN

Carbon capture and storage (CCS) is an attractive area of research in such fields as CO2 mineral carbonation, global warming and sustainable energy systems. In this study, carbonation efficiency for aqueous mineral carbonation (MC) was achieved through two steps,which include leaching of calciumfrom cement kiln dust (CKD) followed by the reaction of pure CO2 with the calcium hydroxide precipitates formed by the hydroxylation using NaOH. Response surface methodology (RSM) with a Box-Behnken design (BBD) was applied to optimize the calciumleaching yield,while the carbonation efficiency from CKD was assessed using RSMwith central composite design (CCD). Optimization of calcium leaching is highly important, as it is a rate-limiting reaction step in MC and also influences and enhances carbonation efficiency. Different parameters including acid concentration (HNO3), leaching temperature, leaching time, and dose of CKD sample were considered in order to optimize the maximum yield of Ca leaching from the CKD sample. In addition, different CO2 flow rates and temperatures were used as parameters for optimizing carbonation efficiency. Two quadratic regression models were developed for each process, i.e. calciumleaching and carbonation. For calcium leaching, a maximum of 98.55% calcium was extracted under the optimal set of acid concentration 4.13 M, 90 °C, 28 min leaching time, and 13.8 g of CKD sample. For carbonation, the maximum carbonation efficiency of 89.2% was achieved for a CO2 flow rate of 1163 cm3/min at 90 °C. Calcium leaching results indicate that the leaching yield was significantly affected by all the input parameters except leaching time. For carbonation, both factors affected the carbonation efficiency, with the effect temperature shown to be greater than that of the CO2 flow rate. Additionally, the predicted results agreed well with the experimental values for both calcium leaching and carbonation processes, with errors of less than 1% and 5%, respectively.

Jun 5, 2020

By Sydney H. Ball

I. INTRODUCTION. DURING the past 50 years the attention of mining-men has been turned to Africa, and within the past decade prospecting-expeditions sent into Central Africa have resulted in the opening-up of several mines. Having recently spent two years in the Belgian Congo for the Société Internationale Forestiere et Miniere du Congo, it is our purpose to outline briefly the mining-conditions in that part of Central Africa. Before it became, in 1908, a Belgian colony, this region was known as the Congo Free State. II. LOCATION AND AREA. The Belgian Congo lies in southwestern Central Africa, west of the continental divide, is illustrated in Fig. 1. It has a coastline of but 20 miles on the Atlantic, but widens rapidly eastward to points 5° north and 14° south of the equator. Its area is 908,000 sq. miles, which is almost one-quarter that of the United States and Alaska, or more than one and one-half times that of Alaska. Stated in other terms, its area is nearly one-third that of the United States, exclusive of Alaska and the insular possessions, or more than that of all the United States east of the Mississippi river. III. TOPOGRAPHY AND DRAINAGE. From north to south, Africa is made up of three topographic elements: 1, the Atlas mountains, a highly-accentuated region

Apr 1, 1910

By D. W. Frommer, L. Bonicatto, M. M. Fine

A mineral - dressing investigation was conducted to demonstrate the ability of an anionic silica - flotation process to produce high- grade concentrates from submarginal iron ores of the western Mesabi and Menominee ranges . Commercially available equipment and reagents were used . Samples from the Menominee range were exclusively from the Groveland , Mich . , mine and contained hematite as the chief iron - bearing mineral . Bench- scale investigations established that the anionic silica flotation method can function effectively on a variety of undeslimed ores . Continuous tests completed on one Mesabi semitaconite ore and on Groveland mill feed , have verified the validity of the bench research . The Mesabi samples yielded a concentrate containing 60.3 percent Fe and 6.0 percent Sio with an accompanying iron unit recovery at 90.5 percent . Iron recoveries from the mill feed ranged from 79.0 to 87.4 percent .

Jan 1, 1964

By William R. Wayment, David E. Nicholson

The Bureau of Mines studied some physical properties of hydraulic backfills and their paramount characteristics , and made preliminary attempts to compact this type of material . The in- place density of hydraulic backfills affects the properties of strength , consolidation , and water percolation . Dense fills give better support than loose fills . In - place density properties themselves are affected by grain size , grain size distribution , and the particular conditions of sedimentation in a stope ( the amount of work the slurry water does to compact the material ) . Field sampling of in - place densities of fills presently used in four different mines and laboratory and underground compaction tests using a standard concrete vibrator show that the initial in - place density of the cohesionless fill material tested can be significantly increased by vibratory compaction .

Jan 1, 1964

By R. R. Hornor, Geo. M. Hunt

The purpose of this paper is to point out some of the benefits and economies to be derived by the better selection , preparation, storage , preservation and utilization of mine timber , and to give some specific information on certain wood preservatives and processes suitable for mine timber preservation . The paper is based largely upon data obtained by actual experimentation and service tests conducted by the U. S. Forest Products Laboratory , Madison, Wisconsin, on wood preservation , covering a period of many years , and upon a field survey during the past summer by one of the mining engineers of the U. S. Bureau of Mines of some of the principal mining districts of Michigan , South Dakota , Montana , and Idaho , in which he made a general ' study of mine timber in metal mines , particular attention "being given to timber decay ; the conditions under which it takes place most actively ; the measures , if any , that are being used to combat it; and, finally, the advantages that might be anticipated in the use of chemically treated timber to prevent decay and thus prolong its life .

Feb 1, 1922

By Yi Yang, CHENGLONG XU, HAORAN LI, YALI FENG, JINRONG JU

This study presents a method for recovering valuable metals and synthesizing anhydrite from steel slag using sulfuric acid leaching and solvent extraction. The process achieved high leaching efficiencies for V, Ti, Fe, and Mg, and produced anhydrite with 93.09% purity. The leachate was further processed to separate and recover V, Ti, Fe, and Mg using selective stripping and precipitation methods, offering a sustainable approach to steel slag utilization.

Jan 22, 2022

By Oliver Bowles

The United States has never attained importance as a producer of asbestos, the domestic output being only 1 to 3 percent of the quantity required to supply raw material for its extensive asbestos-product manu- facturing industries. Production is centered in four principal countries-- Canada, Rhodesia, Union of South Africa, and the Soviet Union. Since asbestos first became an important commercial commodity the Province of Quebec, Canada, has led in tonnage produced, but a large proportion of the output of this province is shorter, nonspinning grades. Since 1916 the Union of South Africa and Rhodesia have become increasingly important as sources of the higher-grade spinning fibers. Before the World War Russia ranked next to Canada as a producer of asbestos, but during the revolution- ary period the industry in that country was almost at a standstill. In 1926, however, activity was revived, and each year since then production and exports have increased greatly. Minor quantities of asbestos are produced in Cyprus; Australia, Finland, and several other countries. Chrysotile is the leading product in all the producing countries, but substantial quantities of both blue (crocidolite) and brown (amosite) asbestos also are produced in the Union of South Africa. Minor quantities of anthophyllite and similar amphibole varieties are mined in the United States, Italy, Bulgaria, Finland, and several other countries.

Jun 1, 1934

By A G. Noble

Tunnelling for hydro-electric power projects can be a very challenging component of the overall development. In contrast to urban transportation tunnelling where the logistics for access and supply of power, water and other essentials are readily available, hydropower projects are usually in very remote locations and all necessary plant, equipment, spares and materials need to be brought in and the site must function as a self sufficient unit.For a large scheme the river diversion tunnel(s) are usually on the initial phase critical path in order to meet the non-negotiable deadline of river diversion before the onset of the wet season. A newly formed tunnelling crew, once mobilised to the site for the project, will face the first major learning curve of the project’s systems and logistics during this critical tunnelling activity.Power tunnels convey the water to the turbines in the powerhouse and are usually on the critical path for the main works, especially if the scheme comprises a powerhouse located within an underground cavern. A modern cavern arrangement requires a complex warren of various openings: access adits, ventilation/cable tunnels, shafts, surge tunnels, etc.Hydropower tunnel construction tends to be dominated by tunnel boring machine (TBMs) or drill-and-blast excavation techniques and each has its challenges in very remote locations. TBMs still have long lead times as for any type of project, but additionally require a thorough roads and bridges infrastructure assessment of the country from the port of entry to the site to ensure a problem-free delivery. In some cases the project also requires the establishment of a complete precast concrete segment production facility and the space for creation of laydown areas; there is no ‘just-in-time’ delivery mechanism applicable to typical remote hydropower sites.This paper highlights the technical and risk management considerations in the planning, design and construction of tunnels for hydropower projects. It contrasts the typical factors that govern the design of urban transportation tunnels with those for remote hydropower tunnels. The perspectives of stakeholders are provided including those of international lenders. With examples from large and small scale projects across the globe it provides an insight to all parties and in particular, those tunnellers that are working in the hydropower field for the first time.

Mar 8, 2011

By Brendan Demich, Joseph McGuire, Emily J. Haas

Near misses recorded and reported by workers can provide awarenessto the potential causes of injury and prompt safety management initiatives. Although most companies require near-miss reporting, it is unclear what the value of these reports are, if any, and how they influence subsequent actions or controls to reduce on-the-job risks. Researchers at the National Institute for Occupational Safety and Health (NIOSH) conducted a case study with an aggregates company in which near-miss reports were analyzed at each of their locations over an entire quarter during the summer of 2018. Within that quarter, workers recorded 249 near misses. Of those, 167 were valid near misses that occurred at work. Researchers coded the reports using a qualitative 5 × 5 risk matrix. Of the 167 near misses, 19% were deemed low risk, 25% moderate risk, 30% high risk, and 26% critical risk. Several patterns in the near-miss incidents were documented, including classification of incidents and common corrective actions referenced (i.e., elimination/substitution, engineering control or redesign, work process/procedures, and personal protective equipment). The analysis provides insight into ways that risk communication and management programs can be improved to reengage workers and their situational awareness on the job.

By N. Theron, R. F. Meeser

The global emphasis on conserving energy resources has led to the adoption of hybrid power systems in vehicles. Optimally applied, hybrid systems can save up to 40% on fuel costs. To optimally manage a hybrid vehicle's energy flow it is necessary to know, in real time, all the energy requirements to complete a given route. The energy consumption depends mainly on the vehicle mass, speed profile, and route topography. Of these, the topographic profile is the one factor that is only route-dependent and not influenced by the vehicle or driving styles. The heading vs. distance profile is also an example of a route characteristic not influenced by the vehicle or driving style. In this study the topographic and heading profiles are used to identify routes, and are easily measured by means of digital barometric pressure and compass sensors. Correlations between the current route and previously travelled/stored routes are performed based on their topographic and heading profiles in a point-by-point manner. Above-ground tests were first performed using a road vehicle and six routes to evaluate the system. The system consistently and correctly identified a 20 km route within the first 4 km. It also proved to function correctly in underground tests through the implementation of an instrumented hand-held surveyor's wheel. This system finds direct practical application in optimizing the energy management of an underground hybrid locomotive used by the mining industry in South Africa, but can also be of benefit in applications where route identification is required and using GPS is not feasible.

Jan 26, 2023

By M. Onifade, B. Genc, P. O. Akinseye, M. Fourie, K. O. Said

Coal is mined by both surface and underground methods and its extraction is normally characterized by numerous hazards that can lead to catastrophic accidents, which result in devastating effects such as injuries or fatalities, damage to mining assets, and destruction of mineral resources. These hazards exist due to the ability of coal to support combustion and its association with toxic, flammable, and explosive gases. Underground coal mining entails higher safety risks than opencast coal mining, chiefly because of issues relating to mine ventilation and mine collapse. Furthermore, coal mine collapses mostly occur due to crumbling of mining supports, especially in room and pillar mining systems. To avoid such adverse occurrences, safety management systems need to be in place. This study reviews the various technological safety systems and principles that are used for safe-rescue and self-escape of miners in underground coal fires, particularly in South Africa, using data obtained from Mines Rescue Services in Carltonville, South Africa. The outcome of the review shows that practising safety culture has been given priority across many South African underground coal mines through setting up safety management systems and encouraging workers to stay committed to safety principles.

May 2, 2022

The long-term outlook Tor Australla's traditional mining products is for flat demand and continuing low prices. This has come about because of three far-reaching changes since earlier boom days: 1. Continuing declines in intensity of usage of basic mine products; 2. The failure of newer western and third world developing countries to realise growth expectations; and 3. Continued production pressure from third world countries (and first-world primary producers) in an effort to earn foreign exchange and rectify trade balances. These trends have led to a general situation of excess supply and weak demand. In this environment, the prerequisites for survival in the mining sector are first-class mines, modern and efficient production methods, low unit costs, aggressive marketing, and products with reasonable operating margins. Many of Australia's mines meet these prerequisites. Following the A$ depreciation and widespread unit cost reductions, most of these mines will be moderately profitable at current depressed commodity prices. They are well placed to benefit from price rises if these eventuate. A new generation of mines is concentrating on a more profitable product range (gold, diamonds, uranium, mineral sands). Australia's balance of trade remains firmly dependent on the primary mining and agricultural industries (Fig. 1). Despite optimistic talk of high-tech developments, tourism and a resurgence of manufacturing, these will remain a small component of Australia's export structure.

Jan 1, 1987

By H. E. James

Much has been said and written about the need to reduce South Africa's dependence on gold. To compensate for the decline in the country's foreign-exchange earnings resulting from the phasing out of gold, which must inevitably occur at some future date, a far higher priority will have to be placed on the mining, beneficiation, and export of the 59 other mineral commodities produced in South Africa. The basic strategy of the mining and metallurgical industries should be to move from the traditional approach of establishing a resource base to the establishment of a market base; to turn from production orientation to market orientation; and to rely less on exploration and economies of scale and more on process innovation and product development. The enthusiasm, entrepreneurial spirit, and commitment of the leaders in the mining and metallurgical industry will clearly be of decisive importance in the establishment of new industries for the beneficiation and export of added-value mineral-based products. The State can make a significant contribution by the provision of a welldeveloped and efficient infrastructure, including rail and harbour facilities, communications and health services, roads, and of electricity and water supplies. In our search for a new development strategy for the beneficiation and export of South Africa's minerals, we need to recognize that no one nation has all the mineralresources that it needs. Commercial and strategic manipulation of mineral supplies should no longer be tolerated. The future of the human species lies in international cooperation and in a greater understanding of the limitations of the world we live in.

Jan 1, 1985

By R Schmitt, Y Ghorbani, I McElroy, N J. Bolin, M Parian

Aitik is a large copper porphyry type deposit located in northern Sweden, currently exploited at an annual rate of approximately 45 Mt. The ore’s exceptionally low head grade of 0.25 per cent Cu and varying degrees of hardness across the entire deposit pose challenges to the two fully autogenous grinding lines, each of which comprises a primary autogenous mill in series with a pebble mill. The variability in ore grindability frequently leads to fluctuations in mill throughput. Within the framework of a geometallurgical approach, the present study investigated the relationships between ore grindability and modal mineralogy. For this purpose, drill core samples from different lithologies were subjected to Boliden AB’s in-house grindability tests. This fully autogenous laboratory-scale test generates a grindability index mainly related to abrasion breakage, which is a significant breakage mechanism within autogenous mills. The test results suggested divergent degrees of grindability within and across the selected rock types. A combination of scanning electron microscopy, X-ray powder diffraction, and X-ray fluorescence analyses was performed for the grinding products and bulk mineral samples. The resulting mineralogical and elemental properties were subsequently correlated to the parameters from the grindability tests. It was shown that the main mineral phases, such as plagioclase, quartz, and micas, correlate well with the grindability indices. Similar correlations were found regarding the sample’s chemical composition, attributable to the main mineral phases. A further inverse correlation was established between the sample’s calculated average Mohs hardness and the grindability indices. Moreover, mineral liberation information provided by scanning electron microscopy was associated with the parameters mentioned earlier. The identified relationships between grindability, modal mineralogy, and element grades may help Boliden develop a predictive throughput model for Aitik based on the mine’s block model.

Aug 24, 2022

The Bureau of Mines human factors research program is directed toward reducing accidents and improving the overall efficiency of the person-machine environment interface found in surface and underground mines. The focus of the hum factors program therefore, is to insure that sound knowledge is available concerning human capabilities and limitations, and that this knowledge is applied to the design, of mining equipment, work tasks, and management procedures. The papers presented in these proceedings summarize some of the recent Bureau research in hum factors. The papers focus on two broad areas, human resource issues and human engineering of equipment, tools, and work procedures found in mines.

Jan 1, 1987

By G. L. Oldright

As sponge iron is much like porous, coarse sand, it is a tempting material to use in place of coarse scrap iron as a precipitant of metals, for scrap iron is relatively awkward to handle and exposes only a small amount of surface to pregnant solutions. The results of the experiments described in this bulletin are largely a record of the behavior of sponge iron as a precipitant of lead and copper under laboratory conditions comparable to those that would obtain in a commercial plant were it attempted to secure the maximum contact of surface between solution and precipitant. Physically, the study is largely one of the rates of diffusion of the metal ions in the solutions and through the metallic coatings surrounding the sponge iron particles. The practical objectives are to remove completely the valuable metals from solution and at the same time to obtain a precipitate of good grade. In order to fulfill this latter requirement, the precipitant should be almost completely consumed. These practical ends are usually secured by having the two substances involved pass each other counter-currently-that is, in such a manner as to have the strongest precipitant in contact with the most impoverished solution, and vice versa. EXPERIMENTS WITH LEAD SOLUTIONS In nearly all of the schemes involving the leaching of lead from its ores the metal has been put into solution as the chloride, and fairly concentrated liquors have been employed. The solubility of lead under such conditions is comparatively small at best; the hot pregnant liquors from which the metal is to be precipitated are then made nearly saturated with respect to lead, and only a very small amount of acid is used. Therefore it was not as necessary to learn the behavior of the sponge iron in precipitating lead from solutions of widely differing composition as to learn under what conditions, and with what mechanisms, this precipitation might be carried out most readily.

Jan 1, 1928

By D. Harrington

United States newspapers of 25 or 30 Years ago ran headlines every few weeks telling of some mine disaster. Each disaster was a first-page attraction for a day or so then was forgotten until the next sensational event, frequently another mine disaster, a few weeks later. Interspersed with the large mine disasters were the so-called ?snipping? mine accidents that caused the death of one or two mine workers. The summation of mine fatalities of all types usually exceeded 3,000 a year, and nonfatal accidents to workers in mines of the country approximated 250,000 annually. From 1906 to 1910, inclusive, there were 84 major explosion disasters (about 17 per year) in. United States coal mines. The resulting fatalities totaled 2,388 for the 5-Year period. These frightful catastrophes helped the number of fatalities in coal mines of the country to reach the enormous total of 13,288 for the 5 years, or an average of 2,658 per year.

Jan 1, 1940

By Joseph L. Jordan

Coal is essential to America?s future energy needs. To meet these needs mining methods must be safe, economical, and environmentally acceptable. Belt conveyor systems for coal haulage from surface mines offer great potential in this situation. The advantages over conventional truck haulage are particularly promising for area strip mines in western coal fields such as the Powder River Basin where relatively thick, flat-lying coal seams occur. The current demand for low-sulfur coal specifically emphasizes the need for better mining methods in these areas. Underspoil haulage is the term applied to transportation of coal from the pit to the surfate in area strip coal mines by belt conveyors in tunnels under the spoil. The advantages over trucks include lower manpower requirements, greater pit safety and efficiency, and improved reclamation procedure. This evaluation includes a comparison of total mining costs for truck haulage versus six variations of the underspoil haulage concept. The more efficient of these underspoil haulage systems have economic advantages over truck haulage which become more pronounced with deeper overburden, thicker coal, and higher annual production.

Jan 1, 1977

The Bureau of Mines is responsible for a broad spectrum of programs for meeting the diverse and changing mineral resource needs of the Nation. These programs are managed by the Director and two Deputy Directors, who formulate general policy and program direction from the Washington, D.C., headquarters. Bureau program activities are classified into two major functions, minerals research and minerals information and analysis. A senior advisory staff, consisting of the Chief Staff Officer and Chief Scientist, provides advice and consultation to the Director on a wide range of scientific and technical matters and acts on behalf of the Director to maintain liaison with other government agencies, both foreign and domestic, mineral industries, and professional societies. The Minerals Research Directorate Technological research and development in minerals have long been cornerstones of the Bureau of Mines. The Minerals Research Directorate performs this work. Re-search functions cover the extraction, processing, use, reuse, and disposal of mineral materials; the reduction of health and safety hazards in mining and processing; and minimizing undesirable environmental effects. The production, conservation, sale, and distribution of helium is also conducted under the Research Directorate.

Jan 1, 1981

By P. A. Cox

The purpose of the initial research performed under this contract was to determine the margins of safety in explosion-proof (XP) enclosures, which were designed and certified according to the current schedule (Schedule 2G). Results from this work provide baseline data on the current schedule, from which a new schedule can be formulated to give equal or greater levels of safety. Results and discoveries in the initial work led to an expansion of the contract to cover, additionally, weld quality in enclosure fabrication, reliability of enclosures with windows and lenses, and performance tests for enclosure qualification. Finite element calculations and hydrostatic tests revealed wide variations in the margins of safety in the enclosures studied; however, only one enclosure had a safety factor which was less than one. Results from a weld quality survey led to the recommendation of AWS Welding Standard D14.4 for the fabrication of XP enclosures. Based on other work, accelerated aging tests were recommended for qualifying plastics and adhesives that are used in some enclosures, and a Structural Performance Test was developed to test enclosure strength for a minimum static pressure of 150 psig.

Jan 1, 1982