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By Shadrack Nuamah, Erik Westman, Bright Afum, Jesse Addy

Rock fragmentation is the most critical aspect of hard rock production blasting due to its significant impact on drilling and blasting costs and the economics of subsequent loading, hauling, and crushing operations. This study analyzes current cost trends in the drill and blast operations of an anonymous open pit gold mine and proposes cost-effective drill and blast geometric parameters. The investigation focused on one operational pit with provided design parameters for two shots, shot 1 and shot 2. Existing blast parameters and two additional proposed sets of geometric parameters were evaluated using the Kuz-Ram and Chung and Katsabanis fragmentation models to estimate mean fragment sizes. The results indicated that the proposed blast parameters produced estimated mean fragment sizes within the mine’s desired range (not exceeding 45 cm). Additionally, the explosive energy was utilized efficiently per in-situ material blasted. The proposed parameters increased the estimated total volume of in-situ material fragmented by approximately 14% for both Shot 1 and Shot 2 compared to the current parameters. Furthermore, adopting the proposed blast parameters could lead to significant cost savings. The evaluated total drill and blast cost savings were approximately 11% for Shot 1 and 12% for Shot 2. These savings stem from the increased efficiency and effectiveness of the blast operations, highlighting the potential for substantial economic benefits. This study demonstrates that optimizing blast geometric parameters will allow open-pit mines to achieve desired fragmentation, utilize explosive energy more effectively, and realize considerable cost savings in drill and blast operations.

Jan 21, 2025

By William A. Bassett

Two very intense sources of electromagnetic radiation are contributing significantly to experimental studies of minerals at high pressures and temperatures: 1) A Q-switched YAG laser is able to produce a pulse of infrared radiation capable of heating a sample under pressures up to 400 kbar in a diamond cell up to temperatures in excess of 4000°C. 2) X-rays from the Cornell High Energy Synchrotron Source (CHESS) are used to obtain diffraction patterns of samples In a diamond cell in less than two minutes, patterns that would require hundreds of hours on a conventional source. The laser heating technique is being used to study the pressure-temperature conditions over which the melting of diamond takes place. In the initial stages of this investigation, diamond has been melted and techniques for detecting the melting have been developed. The intense X-rays from the synchrotron source have been used to examine the mechanism and rate of the pressure-induced phase transformation in Fe2Si04.

Jan 1, 1985

In the interest of safety ii: coal mining, the Bureau of Mines recommends: That all active underground coal mines, whether working or idle, have one or more fans in continuous operation. The capacity and installation shall be such that the entire mine workings are adequately ventilated at all times. Main fairs shall be located on the surface in fireproof housing offset from the line of any mine opening. The housing shall be provided with ample pressure-relief doors or other devices easily opened by the force of an explosion. The installation shall permit prompt reversal of air flow. For mines that liberate gas, the fan shall have at least two independent sources of rower immediately applicable. Ventilation of underground workings in coal mines is needed whether or not explosive gas is present. Natural ventilation is unreliable and often uncontrollable. Main fans should be on the surface; if they are in the mine, fire or explosion may make access difficult or dangerous and render the installation inoperative.

Jan 1, 1939

By L. Gutierrez, S. Gering, C. Calderon-Arteaga

"INTRODUCTION Drill and blast (DnB) represents the most important, and sometimes the most costly processes in a mine.. The cost of drilling and blasting operations greatly contributes to the “high cost trends of the overall mining operations” (Afum B. O. and Temeng V. A. 2015). The use of available information to improve the DnB processes can be the difference between a highly expensive process and an optimized one. Mining operations have access to several types of data sets and key information from a wide variety of different systems. This information is normally used to improve, evaluate and apply processes for drilling and blasting. This may include different types of data from the different stages of the process (before, during, and after the drilling and blasting operations), such as hole locations (planned and actual), penetration rates, drill operators, fragmentation (expected and resulting), explosive (design and usage), geology, vibration, and others. This information can be used on its own or combined for further analysis to reduce costs, improve safety, and evaluate results. Fortunately, due to advances in mining software, drill and blast engineers can exploit this data and create reports to evaluate results and improve the DnB process. However, as users start combining information from multiple datasets and establishing standard operating procedures for reporting this data across multiple sites, it becomes valuable to create auditable, automated, and sustainable processes for handling the information. In many cases the task of aggregating and standardizing the data formats has already been completed and is available to consumers via the Enterprise Data Warehouse (EDW). A data warehouse team extracts data from the source systems and transforms it so that it is meaningful for decision support (Barbara H. Wixom, Hugh J. Watson, 2007). Our initial implementation plan for the DnB solution included using data stored at the sites; however we learned early on in the process that much of the work for aggregating and supplying the required data was already completed. The goal for this case study is two-fold: to show how information can be used to make decisions and improve processes, highlighting the value of using an EDW for managing Drill&Blast information; and to discuss how technical challenges encountered during the implementations were resolved. This paper is targeted at users that want to better manage their DnB data or try to set up standardized workflows for using this information. This case study will discuss the process of implementing a DnB workflow at multiple sites within Freeport McMoRan Inc (FMI) using both data at the sites and information available using the EDW. The paper will begin with an overview of the project. The discussion will then describe how DnB processes were used to set up daily workflows in order to provide information for evaluating process and making decisions. The final section will discuss some of the technical challenges and how they were solved, as well as possible next steps for further improving the workflow."

Jan 1, 2017

By A. Mull, J. Weyer, J. Brune

"The “Reiche Zeche” mine in Freiberg, Germany, a 600-year-old lead-zinc-silver mine with extensive open mine workings, experiences severe ventilation losses due to leakage. Much air leaks into abandoned workings, decreasing the airflow available to active working areas. Usually, this leakage occurs in remote areas that lack transportation infrastructure like roadways or rail, making it difficult to haul construction materials to the sites to erect passive ventilation controls such as stoppings, regulators and seals. Transportation distances make it impractical to hand carry traditional construction materials, such as bricks and concrete. Alternative materials, such as brattice, foaming polymers, concrete canvas, and some innovative ventilation control designs have been investigated for this purpose. The suitability of the materials investigated depends on many factors including the pressure it can withstand, the ease of transportation, and workability. Impacts of mine water must be considered, as the Reiche Zeche is below drainage and experiences significant inflow of water. Researchers must consider the effects water inundation as well as how the stopping construction material reacts to being exposed to acidic mine water. INTRODUCTION Problem Statement Mining in the area around Freiberg, Germany began in the 12th century. The mine is used for research, mining engineering education, tourism and air conditioning for a local hospital. The first records of mining in the Reiche Zeche are from around 1384. Due to the strength and competency of the host rock, many of the oldest workings still stand and remain open today, although they may not be accessible. Reiche Zeche also connects to several other, closed mines in the area that are largely unmapped. This allows air to leak into neighboring mines, reducing the air available to ventilate to the working areas of Reiche Zeche. In order to improve ventilation efficiency, it is necessary to control the ventilation and reduce leakage by constructing seals, stoppings and regulators. A challenge with building traditional seals and stoppings in the Reiche Zeche is that the old workings lack transportation pathways or rails. Also, the lack of compressed air, water or electricity makes it difficult to operate power tools and drills. This means that construction materials must be hand carried – some over distances of several kilometers. Figure 1 shows a typical drift in the Reiche Zeche. Researchers investigated using lighter, more easily transportable materials including concrete canvas, expanding polyurethane and polyurea foams, and brattice. The applicability and utility of these materials depends on a variety of factors including the ventilation air pressure, chemical resistance to acidic and mineral-laden mine waters, ease of transport, and ease of construction. Stoppings and seals must be substantially constructed so that they remain tight and do not require maintenance. It is also important to consider the toxicity of the construction materials in case of a mine fire."

Jan 1, 2016

By J. C. Agarwal

Do large-scale projects in mining and smelting start up and achieve expected capacity on schedule? In most cases not. Regardless of worldwide location, company know-how, or financial backing, unforeseen delays occur. A comprehensive CRA study for the World Bank shows that delays are the rule, not the exception, in most mining and smelting projects. When delays are not factored into analysis and planning, financial projections are, literally, not to be believed. Returns on investment will seldom achieve their targeted level because of startup delays. This paper reviews the results of our analysis of startup of new mines, mills, and smelters; provides a detailed discussion of why delays occur in the smelters and refineries; presents the cash flow implications of startup delays; and discusses preventive measures that should be taken to avoid financial shortfalls,

Jan 1, 1983

By B. Morrison

"The Kiruna Electric System is a recently developed inclined ore haul age system for underground mining operations. Although an initial investigation was carried out at the Swedish underground iron ore mine LKAB almost three decades ago, it was not until 1981 that the resources of LKAB, ASEA and Kiruna Truck AB were combined to investigate, and subsequently develop an ""all- electric truck"" for the mining industry.It has long been appreciated, that major economical advantages could be realized by a mining operation through an extension of the cost-effective life of the existing ore hoisting system by the use of ramps to haul ore up to the main haulage level. Diesel truck s have been used and are being used for ramp haulage. Their use however, is limited due to ventilation and operating costs restraints.There are numerous instances of orebodies, located within a couple of hundred metre s of surface, or below an existing hoisting facility, being developed by ramp access while the shaft is being sunk. Development of an orebody via ramp access has many advantages to a mining operation where mechanized mining is to be practiced. These advantages are both practical and economical; generally falling within the over-all umbrella of the phrase ""cash flow"" mining.The decision to sink a shaft is a major committment by any mining company, regardless of size and financial reserves. Extensive diamond drilling, both shallow and deep must be carried out before a decision can be executed. This constitutes a major financial expenditure over an extended period of time.The decision to sink a shaft must be weighed against the reliability of geological interpretation of the deep diamond drilling results, the stability of the mineral market and potential fluctuation in ore prices and interest rates."

Jan 1, 1989

By A. P. Pavia

Investigation on profitable ways to recover significant quantities of silver remaining dissolved in highly concentrated chloride solutions frequently pass through the development of solvent extraction (SX) routes. In this work, the general pathways involving Ag(I) extraction by dibutylthiourea (DBT) or tetraethylthiuram disulfide (disulfiram, DSF), from concentrated acidic chloride solutions, are investigated. With this purpose, the dependence of Ag(I) distribution coefficient on ligand and chloride concentrations has been analysed. Furthermore, in order to check whether there is some protonation at any site of DBT or DSF after contact with adequate chloride phases, lH NMR has also been used. The collected spectroscopic data suggest that anionic Ag(I) extraction reactions are not likely to occur. Based on the overall results achieved, proposals for the most probable Ag(I) extraction reactions are made.

Jan 1, 2001

By S. M. Rupprecht

"SynopsisOver the last decade in South Africa, there has been a significant increase in the number of mining operations, both open pit and underground, which use independent contractors to carry out mining activities. Often mine owners will choose the contractor option without fully understanding the consequences of undertaking this option. Traditionally, contract mining has come at a cost premium of about 15% to 20% compared to an owner mining scenario. However, due to the large number of junior mining companies entering the mining arena in South Africa contract mining rates have increased, with cost premiums as high as 50% being reported. This paper looks at the merits of owner mining versus contract mining and describes under what conditions it may be favourable to select the one option over the other. In addition, the methodology of entering into contract negotiations with the objective of establishing a fair and sustainable relationship is discussed.IntroductionOver the last decade in South Africa, there has been a significant increase in the number of mining operations, both open pit and underground, which use independent contractors to carry out mining activities. Surface mining, for example, may use contractors to conduct drilling and blasting operations or load and haul operations. Underground mining may contract out work such as shaft sinking, mining, support, construction work, cover drilling, sweeping and vampings. Common surface operations such as mineral beneficiation, waste disposal, security, and product transport may also be outsourced to contractors.Many companies have a business model that utilizes contractors for the entire mining cycle, maintaining a small head office to provide direction and control. The difficulty with this option is that often mining companies will choose the contractor option without fully understanding the implications."

Jan 1, 2015

By H. W. Camp

The past year has had no revolutionary change in the process of petroleum refining, although there have been improvements and developments in practically every phase of operation, due largely, perhaps, to economic pressure. A few years ago, a Mid-Continent skimming plant using 35 gravity crude obtained 28 per cent. gasoline and naphtha; 9 per cent. kerosene, and the remaining yield gave gas oil and fuel oil. Figuring manufacturing cost, but not including sales, transportation, overhead and depreciation, the realization was $1.45 per bbl. of crude. Today, a thoroughly modern and up-to-date skimming plant, having all latest equipment, shows a realization of $1.74 per bbl. on the same basis. Thus it is evident that progressive developments have taken place in the last 2 or 3 years when potential earnings have been increased about 20 per cent. The average refiner is compelled to exert his utmost ingenuity in order to operate with a profitable margin. He has two factors to consider—recovery of maximum yields of profitable oils and the reduction of operating expenses. For the past 8 years, the margin between price of gasoline and cost of crude has grown narrower, constantly. Both these prices are determined by external conditions and not by the refiner himself, but the refiner might have been able to increase that margin had he more carefully controlled his output, limiting his production of light oils to current consumption. Be that as it may, this same economic pressure has given impetus to progress in improvements of primary distillation equipment, including stills, towers and heat-saving devices. A pipe still and bubble cap fractionating equipment can now replace a battery of shell stills, giving better yields, better control, elimination of rerunning and lowering of operating costs. The most recent pipe stills are being equipped either with radiant-heat furnaces or air-preheating systems and improved heat exchange equipment. These can be operated on a fuel consumption as low as 1 per cent. of the charge as compared to a fuel consumption of

Jan 1, 1929

By Jamai Rostami

Mining, perhaps more than other industries, has been under pressure to achieve higher productivity, while reducing costs and environmental impacts. This has encouraged a move toward large-scale operations and greater integration and automation of systems. Mechanization is being used increasingly to raise production and reduce labor requirements. Yet, while transportation, ventilation and other activities have benefited from this trend, mechanization of rock excavation (for development and production) has lagged. The switch to a mechanized excavation system can be complex, requiring a thorough study of operational and cost benefits to be successful. To justify the high capital cost of mechanical mining equipment, production rates and the true costs of machine mining must be accurately estimated. To evaluate the cost effectiveness of mechanical mining for a particular operation, the total production cost (capital and operating) must first be estimated. This requires a reliable estimate of the production rate of the candidate mechanical excavator. Previously, the variable nature of rock caused performance prediction of these machines to be more an art than a science. Additionally, some of these machines are highly sensitive to operator skill. They all depend on their backup systems. The effects of interaction with the overall mining operation can be difficult to forecast. And a new system must surmount psychological barriers before it can become truly operational.

Jan 1, 1994

By T. A. Evans

The Bureau of Mines conducted a Laboratory and pilot-plant investigation of the flotation of iron sulfides from zinc-lead mill tailings near Platteville, in south-western Wisconsin, at the North Central Experiment Station, Minneapolis, Minn. The procedures used and the results obtained in this investigation are described in this report. Samples for laboratory tests were obtained from each mill in the district, namely, Calumet & Hecla, Inc., Eagle-Picher Co., Vinegar Hill Zinc Co., and Tri-State Zinc, Inc. The sample fat pilot-plant work was obtained from the Davis Mining Enterprises mill.

Jan 1, 1957

By J. M. Lottering

Paper written on project work carried out in partial fulfilment of B Eng (Chem) degree Operational factors influencing the electrostatic separation of mineral sands were investigated in a laboratory separator. Measurements were collected online by means of an optical sensor using diffused reflectance spectroscopy to determine the mineralogical composition. The results have shown that the roll speed and potential were the dominant operating variables, collectively explaining more than 83% and 68% of the product grade and yield, respectively. In contrast, the feed rate, temperature and position of the plate did not affect separation. The effect of the ambient relative humidity, ranging from 10% to 45%, could not be assessed conclusively and at best appeared to have a weakly beneficial effect on the product grade. Keywords: process modelling, high tension roll separator, mineral sands

Jan 1, 2006

By J. M. Stuve

The standard heats of formation (?Hf°) of holmium trichloride and terbium trichloride were measured by solution calorimetry. Heats of solution of holmium and terbium metals and their anhydrous chlorides were measured in 4.360 molal HCI at 298.15° K. From these measurements ?Hf° for HoC13 (c) was calculated as -240,290 ±1,700 cal/mo1e, and ?Hf° for TbC13 (c) was calculated as -238,330 ±1,500 cal/mole at 298.15° K.

Jan 1, 1967

By George S. Rice

"The successful use of the gas mask by the American Army it France in combatting the poisonous gases of German .shells caused many Army men to feel that the as masks were proof against any kind of gas which might be encountered. The result has been that from time to time there have been reported in the press, deaths of former army men through using their masks to enter various kinds of gases such as illuminating gas, gasoline vapor, and the gaseous atmospheres produced by mine fire. Such a case has just been reported from a mine, in Copperopolis, California, where a former Army man lost his life in descending a mine shaft filled with the fumes of a mine fire. Another man who, in attempting to rescue him, merely used a dust respirator, lost his life also.While the American type of the Army gas mask was developed by the Bureau of Mines for the War Department, and since the war a section of the Bureau's in¬vestigative force has been developing industrial gas masks for certain specificgases, the Bureau has repeatedly called to the attention of the public the fact that such masks have serious limitations and in no case should a gas mask be used in underground workings for the reason that there may be an insufficient amount of oxygen to breathe, (and the gas mask does not supply oxygen) or there may be present carbon monoxide, which the Army mask will not remove, and there always is some carbon monoxide produced by a mine fire or by a coal-mine explosion, or by a blast of dynamite or other explosive.It is true that the Bureau has been developing a mask which may take care of a small percentage of carbon monoxide, that is, one per cent and under, but in mine fires and after explosions, there may be, and frequently is, a much larger percentage of carbon monoxide in the mine atmosphere. Masks such as these, for small percentages of carbon monoxide and associated gases are for use in connection with industrial surface plants, as for example, on the top of a blast furnace or around gas producers in the open air."

Oct 1, 1920

By Maurice Cook

A procedure of obtaining specimens of lead, tin, and cadmium with a moderately equiaxed structure and a smooth surface suitable for etching without grinding and polishing is described; the advantages of general oblique illumination (as opposed to vertical illumination) in the photomicrography of pure metals .are stated. Using these methods, a statistical study of the changes brought about in deformed lead, on annealing, has been made. The common mode of structural change was found to be recrystallization. Cases of growth of one original grain into another were rare; but if a totally recrystallized specimen was annealed above 200° C., a few large grains appeared and spread over the whole area, except for a certain number of small grains which remain unabsorbed. The temperature needed to produce structural change in lead was found to be lower, the greater the degree of deformation. With tin, an extension of 28 per cent. caused practically no recrystallization at ordinary temperatures, but recrystallization occurred if the specimen was heated to 100° C. In cadmium at low temperatures, the grain size decreased in marked manner as the deformation increased; but at high annealing temperatures, the grain size was comparatively independent of the degree of deformation. THE structural changes in metals brought about by annealing following a deformation at a low temperature has been the subject of many investigations. No less than eleven metals and alloys have been studied in some detail; namely, aluminum,1 tungsten,2 iron,3 copper,4 gold,5

Jan 11, 1924

By B, J Bianchini, N Voermann, C Crowe

Operational and economic imperatives in the metallurgical industry have led to numerous advancements in furnace design. Modern furnaces provide high production rates, high percentage online time, long campaign life between rebuilds and safe operating conditions. Current trends for maximising plant efficiency include increasing the throughput of existing process vessels (often by a factor of two or more) and the use of newer, highly intense processes. In both instances, the process intensity results in the generation of higher heat fluxes to the crucible walls. High-intensity furnace operation with the objectives mentioned above has become possible with the following furnace design features: Strong sidewall cooling systems, using copper coolers, to accommodate the high heat fluxes encountered while protecting the crucible refractories; Robust, spring-loaded furnace horizontal and vertical binding systems which maintain tight brick joints through-out all stages of operation; and Well-designed, intensely cooled tapholes for metal, matte and slag. The integration of these features along with properly selected refractories, appropriate instrumentation systems and efficient water-cooling systems is also highly critical. These design features have been successfully implemented in electric smelting furnaces, flash smelting and converting furnaces (Outokumpu and INCO types) and lance injection furnaces (Mitsubishi, Ausmelt and Isasmelt types). This paper will discuss design aspects and operating results for several installations.

Jan 1, 2002

By Kendall Y. Keuhey

The Mercur Mine, developed and operated by Getty Mining Company, is designed to process 3,000 tons/day of gold ore from the historical Mercur Hill mining district. The mill process involves crushing, grinding, and cyanide carbon in leach for recovery of gold ores ranging from 0.08 to 0.10 oz/ton. During the mining of normal grade ore, a substantial tonnage of material containing 0.02 to 0.05 oz/ton is mined and would be available for heap leaching. Also, Getty Mining is developing methods to test and prepare lower grade material for heap leaching by rejecting a course rock fraction from the grinding circuit SAG mill. This lower grade fraction is suitable for heap leaching, and its removal will upgrade the regular mill feed. Other test methods are directed toward leaching techniques on some 4.0 million tons of tailings that resulted from roasting and/or cyanide leaching Mercur ores in the early 1900s. The natural carbons associated with the Mercur deposits require special treatment to reduce their gold adsorption effects when leached with cyanide.

Jan 1, 1983

By Robert A. Jankowski, George E. Niewiadomski

INTRODUCTION The utilization of longwall mining technology in the United States has steadily increased since the first longwall plow system was installed in 1952. At the errs of FY 1992, some 76 coal mines were employing longwall mining systems for coal extraction, and approximately 78 shearer and 3 plow faces are operating nationwide at any given time. Although the number of operating longwalls has remained relatively constant over the last five years, longwall production levels have increased significantly during this period. During the same timeframe, the number of continuous miner sections has decreased by 13 pct., from approximately 1438 in FY 1988 to less than 1250 in FY 1992. According to Mine Safety and Health Administration (MSHA) data, the average production of longwall sections increased from approximately 2400 tons per shift (tps) in FY 1988 to more than 3100 tps FY 1992. In fact, the average production has more than tripled since 1978, when it was only 850 tps. Approximately 25 pct. of operating longwalls are capable of producing in excess of 4000 tps. Longwall production currently accounts for nearly 36 percent of U.S. underground coal production, compared to 4 pct. in 1978. These improvements are attributed to improved longwall equipment and increased availability, larger longwall panels and automation. While longwalls are highly productive and offer other advantages, operations employing this method of mining continue to experience dust compliance problems more frequently than other mining system. Although dust levels have remained relatively unchanged over the past five years, averaging 1.6 mg/m3 and 1.9 mg/m3 based on results of operator and inspector sampling, respectively, during FY 1992, approximately 25 pct. of the operating longwalls were in noncompliance during any given bimonthly sampling cycle. Although modest gains in longwall dust control technology have been made, these have been overshadowed by significant increases in production rates. As more coal is mined, more dust is generated (Figure 1). Therefore, the increase in longwall productivity has meant that far more dust is being produced which must be controlled. [ ] In view of the current compliance record, any efforts to further increase longwall output, as has been forecasted, must be accompanied by: (1) the reduction of dust levels at existing operations through the proper installation and maintenance of suitable engineering dust controls; and (2) the advancement of dust control technology for today's and future longwalls that will enable all face personnel o work in an environment that is free of excessive levels of respirable coal mine dust. MSHA'S RESPIRABLE DUST CONTROL PROGRAM Since 1972, federal regulations have required each coal mine operator to continuously maintain the average concentration of respirable dust in the mine atmosphere during each shift in the active workings at or below 2.0 mg/m3 through the application of environmental dust control methods. The regulations provide for further reduction in the dust standard whenever the

Jan 1, 1993

By F. Peter

I. GENERAL INTRODUCTION. TECHNICAL progress takes place in two directions: the improvement of methods, affecting the quality of the product; and increase in the economy of operations, affecting its cost. In the iron-industry, practice is pretty well settled, and. revolutionary changes of method are, for the present, not to be expected. Hence, in this industry, the principal endeavor is to reduce costs by the use of labor-saving inventions, such as the machines brought into use during the last decade. But it is not alone necessary to reduce the labor-cost; complete economy requires also a saving in raw material. Under this head we may rank the coal employed as metallurgical fuel; and it follows that progress includes the economic use of fuel, so managed as not to injure quality of product. In the present paper it will be shown how, by suitable utilization of the heat from the furnace, a large portion of it may be made available for other purposes. Such utilization of waste-gases is important in all industries which employ furnaces (especially heating- and smelting-furnaces); and in the first rank of these stand the iron-, glass-, and porcelain-manufactures. The following pages are devoted chiefly to the waste-gases of smelting-works, and especially to those reverberatory-furnace gases which are not combustible.'

Jan 12, 1913