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By Yang Song, Li Shaokang, Wang Zhiqiang, Wang Jinjun, Li Guofeng, Su Meixuan

The paper investigates the triboelectric charging properties of calcium carbonate (CaCO3) particles under different conditions using a cyclone tribocharger. It explores the effects of airflow velocity, tribocharge material, and particle moving distance on the charge-to-mass ratio of CaCO3 particles. The study aims to provide guidance for the design of triboelectric separation systems for magnesite.

Sep 1, 2023

By Kumara S. Rachamalla

Long-term stability, appropriate taxation and incentive policies are essential to attract and stimulate investment in the mineral sector. An outline of Ontario's $4.6 billion industry and associated tax incentives is presented. Producers are offered incentives under The Mining Tax Act, federal and provincial income tax acts for exploration and development by reducing Me after tax cost to 13-25¢ for each dollar spent. The Mining Tax Act provides generous processing incentives which have positive effects in enhancing investment and economic advantages of building processing facilities. Non-mining companies and entrepreneurial individuals can receive 25% of eligible exploration expenditures in grants/tax credits under the Ontario Mineral Exploration Program.

Jan 1, 1982

By Dan Nilsson

INTRODUCTION There are many mine planning factors in sublevel caving, as in the other mining systems, which when varied can substantially alter mining costs and profit¬ability. In this chapter, the following four topics are addressed with regard to economic optimization of sub¬level caving: production planning, haulage level spacing, orepass spacing, and extraction cutoff. The costs used here are the right order of magnitude but since each mine is unique, they should be considered only as examples. The objective is to demonstrate the tech¬niques which can be used. In a real mine, the evalua¬tions must be done using actual costs and conditions. It is difficult to predict exactly the costs involved, and therefore it is valuable to perform a sensitivity analysis to evaluate the effect of making incorrect as¬sumptions. Since the mining industry is very capital intensive, the effect of the interest rate must also be studied. PRODUCTION PLAN FOR AN IRON ORE DEPOSIT Introduction The first and most important thing to do before de¬signing an underground mine is to establish a long-range production plan. Such a plan is necessary for all eco¬nomic evaluations and should provide information about the lifetime of the mine, how much ore and waste must be handled per year, how much development per year is required, etc. An example is given in the following section. Problem In an iron ore mine sublevel caving is used. The iron content is 42%, and the mine supplies a pelletizing plant with an annual capacity of 3 million t/a. The ore body is shown in Fig. 1. The length of the ore body is 1000 m and the width is 100 m. Each slice is 10 m high, and there are 10 m be¬tween crosscuts, each of which has an area of 20 m2. The density of the ore is 3.5 t/m3. The spacing between rings is 2 m, and the extraction is 100%. The iron con¬tent is 66% in the pellets and 6% in the tailings. The problem is to develop a detailed production plan. A typical sublevel caving sequence is shown in Fig. 2. Solution Amount of ore per meter of crosscut: 20 X 3.5 = 70 t. Number of crosscuts per slice= 100. Length of crosscuts per slice: 100 X 100 = 10 000. Ore from crosscuts per slice = 10 000 m X 20 m2 X 3.5 = 700 000 t. Number of sublevel caving rounds per slice: 10 000/2 = 5000. Area for each blast in sublevel caving: 10 X 10 - 20 = 80 m2. Amount of ore per blast: 80 m2 X 6 m X 3.5 = 560 t. Extraction: 100% (see extraction curve Fig. 12). Loaded ore per blast: 75% or 420 t. Loaded waste per blast: 25% or 140 t. Total: 560 t. Total amount of rock from each blast in the sublevel caving: Ore: 560 t of which 2 X 70 = 140 t from develop¬ment work and 420 t from sublevel caving. Waste: 140 t. Total: 700 t. The ore needed per year is 3 X (66-6)/42-6 5 mil¬lion t. Necessary number of blasts per year= 5,000,000/ 560 = 8929. Distance to develop per year = 8929 blasts per year X 2 m per blast 17 858 m. Total amount/year: Ore from development work 17 858 m x 70 t/m = 1.25 million t/a Ore from sublevel caving: 8929 blasts per year X 420 tons per blast = 3.75 million t/a 5.00 million t/a Waste rock dilution: 8929 blasts per year X 140 tons per blast 1.25 million t/a Total amount to hoist 6.25 million t/ a The amount of ore from development work will in¬crease a little if the horizontal drift is placed in the ore body and not in the footwall. In this example the ore loss in 20%, and the waste rock dilution is also 20%. After taking the ore loss into account, the lifetime for 100 m of the ore body will be:

Jan 1, 1982

By Kexin Cai, Isidro Rivera, Shawna Von Stockhausen, Maria Chastka, Kevin Huynh

The Newell Creek Dam Inlet/Outlet Replacement Project is located approximately 11 miles north of Santa Cruz, California along Highway 9 in the San Lorenzo Valley. This project will replace the existing inlet/outlet works at the Loch Lomond Reservoir by constructing a tunnel using conventional excavation methods while simultaneously drilling three intake shafts to intercept the tunnel from within the city’s water supply. This project will improve the system’s overall operational efficiency and performance, and provide a safe and reliable facility for the City of Santa Cruz’s drinking water supply. This paper discusses the overall project configuration, construction observations, and challenges during construction, including tunnel excavating through the marine sedimentary siltstone of the Monterey Formation, probing and pre-excavation grouting, and the tools utilized to manage the project.

Dec 1, 2022

By Henning R. Norbom

Lime has been produced for many centuries. The simple pot kiln was one of the first devices used in this process. It was constructed of stone often on the side of a hill to reduce construction efforts and provide easy access to the top for feeding of limestone. It was fired from below with wood and coal. The pot kiln was very small and operated on the batch principle. The kiln being cooled between each batch, the fuel consumption was horrendous. The lime quality was poor with perhaps only one half of a batch being lime of suitable quality. Of the remaining half one part would be over burned and another part underburned. For centuries the lime burning technique was improved at a barely recognizable rate. One of the first major steps forward was the introduction of the continuous process vertical lime kiln. Although at first crudely constructed, the kiln had a refractory lining. It was charged with alternate layers of limestone and solid fuel usually in the form of coke. Continuous mode of operation, larger unit size and better heat distribution resulted in greatly improved fuel economy. However, quality of lime produced still left much to be desired. One problem was contamination by ashes from solid fuel.

Jan 1, 1978

The 31st annual American Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Tucson Starr Pass Resort on Saturday, Dec. 7, 2013. Each year, one living inductee, two Medal of Merit recipients, honorees from mining?s past, an industry partnership award, as well as a special citation, are recognized by the MFSW for their respective contributions to the mining industry. James D. Toole, past president and chief executive officer of Southwest Energy LLC, will be the Hall of Fame inductee, guest of honor, and featured speaker at the awards banquet. Toole founded Southwest Energy LLC in 1973 and is credited with introducing innovative explosive technology, providing even greater value to its mining customers. Medals of Merit will be awarded to Joseph M. Keane, principal metallurgical engineer for SGS Metcon Research/KD Engineering, and Sean D. Dessureault, associate professor at the University of Arizona. Keane is recognized for his metallurgical expertise, especially in design development and pollution abatement. Dessureault is recognized for his advanced mining research, with more than 25 journal publications, and his entrepreneurship as the founder and chief executive officer of two mineral-related companies. To honor mining?s past, the hall of fame will induct Bartolomé de Medina for his invention of the patio process for recovering silver; Ben Williams for his management of the Copper Queen Mine in Bisbee, AZ; Charles E. Mills for his contributions at Morenci and Inspiration Copper and founding Apache Powder Co. and The Valley National Bank; John S. Finlay and Edwin B. Royle for their invention of the mucking machine; and Louis Caryl Graton for his ore deposits research and teaching economic geology at Harvard University.

Nov 1, 2013

By S. N. Chadha

INTRODUCTION The work described here refers to the Genesee River Interceptor Southeast Project. This project is a part of the Combined Sewer Overflow Abatement Program, Phase I, for the Rochester Pure Water District, Rochester, New York. Our contract required the design of a 13,200-feet long main tunnel, 14 feet finished diameter, approximately 100-120 Feet below ground; drop shafts and diversion tunnels to deliver surface flow to the main tunnel; a gate chamber whereby the main tunnel is dropped 35 feet, and provision made for connection to the future tunnel in Phase II, as well as a host of other surface structures. Cross sectional dimensions for the structures involved varied from 16 feet circular to a 20'x50' horseshoe, in a competent rock formation consisting of Lockport Dolomite and Rochester Shale. In the construction of a rock tunnel, the problems of the tunnel designers are as follows: 1. To evaluate stresses in the rock as a result of excavation. 2. Design a temporary support system to prevent any rock failure during the period of construction. Design of this temporary support system is empirical. Design loads given by empirical relations are dependent upon the rock quality and size of opening. Temporary support system may either be steel frames closely spaced along the length of tunnel and tied together, in the case of poor rock, or, an even spacing of rock bolts in the case of competent rock. 3. Design a final lining for the service loads. Service loads, in our case of a water-carrying tunnel, are hydrostatic pressure due to ground water, deadweight of lining) pressure of contained water and time dependent rock loading. The constitutive properties of the rock are extremely complex because of discontinuities, pre-existing stresses due to overburden, material symmetries and changes of initial state associated with the process of excavation. The changes of initial state may be changes of stress fields along with the consequent yield of the material or the extension of existing discontinuities.

Jan 1, 1977

By Ted H. Eyde

Improving the mineral industry's tarnished image describes in a nut- shell the reason why the Speakers Bureau of the Tucson Subsection of the AIME was formed. Let's go back in time about 3 years to the fall of 1971. Literally thousands of bills detrimental to the mineral industry were being introduced into Congress and State Legislatures. Unfortunately, many were being passed and signed into law. Clean air and water, zero pollution, preserve the environment, ecology, biodegradeable, wilderness were the words that the self- styled ecologists and environmentalists were preaching. The mineral industry either sat mute or in place of acting, reacted in a way certain to attract a maximum amount of bad publicity with a minimum amount of rhetoric. A mining company president, for example, commenting on the primary air standards in Arizona was reported by the press as having said, "we'll shut all the smelters down and put thousands of Arizonans out of work if we have to meet the Arizona standards." Or another defending a poorly planned highly visible open pit nonmetallics operation, "we'll take the whole mountain down if we want to, and nobody can stop us" and still another manager of Operations, "the bottom line is all that counts, to hell with all of this environmental nonsense."

Jan 1, 1975

By George Fumich

The Office of Coal Research has been supporting the development of processes for producing synthetic pipeline gas from coal since 1964. .Some of this work has also been jointly supported by the American Gas Association. The work has progressed through laboratory investigation, to bench scale, to pilot plant. It was far from a crash program, generally being fund-limited.. As of one year ago, we had reached the following position: 1. The Institute of Gas Technology HYGAS. process pilot plant in Chicago, Illinois, was in the process of being finally completed. This plant is designed to produce about 1,500,000 cubic feet of pipeline-quality gas per day from 75 tons of coal. 2. The Consolidation Coal Company, CO2 Acceptor Process pilot plant in Rapid City, South Dakota, was well._ on its way to completion. This plant, designed primarily for lignite and subbituminous coals, has about one-half the design capacity of the HYGAS plant. Additionally, the initial construction did not provide for cleanup and methanation; only the preliminary synthesis gas is produced. 3. The Bituminous Coal Research, Inca, BI-GAS pilot plant was in a preliminary design stage. A site had been selected near Homer City, Pennsylvania, to build this plant, planned to consume 120 tons of coal per day. Meanwhile, as you are all well aware, a natural gas shortage was developing in this country. Much has been published about it, so I will not. bother you with further details. Suffice it to say that the reserve-to-production ratio has been steadily declining, because we have been using.-as-faster than we have been find-

Jan 1, 1972

By Thomas P. Meloy

Comminution is an old art. Unfortunately the analysis of the unit operations has been handicapped by the lack of both theoretical and experimental information. Two types of infor¬mation are needed, one an understanding of what happens when a particle breaks in a brittle manner; and two, an understanding of what happens when the daughter fragments pass through the mill. This paper is concerned with the former, the catastrophic fracture of a brittle solid. Recently, successful theoretical attacks on the frac¬ture of brittle solids have yielded significant-results. New experimental techniques are yielding insight into the physical phenomenon occurring during brittle fracture. Many of the re¬doubtable shiboliths of the last century are either being laid to rest or verified.

Jan 1, 1965

By K. V. Raj, C. A. Berry, A. T. Weakley, A. L. Miller, P. R. Griffiths, D. A. Parks

Diesel particulate matter (DPM) has been classified as a carcinogen to humans by the International Agency for Research on Cancer. DPM exposure is therefore regulated by the U.S. Mine Safety and Health Administration (MSHA). The current monitoring process takes days or weeks for exposure levels to be known, and a real-time monitoring device is needed. It is believed that infrared spectroscopy has potential for use in a real-time, field-portable device. This paper presents a method for measuring organic carbon (OC) and elemental carbon (EC) in DPM for a broad range of OC/EC ratios. 

By Atta Ur Rehman, Kwame Awuah-Offei

This work evaluates the effectiveness of similitude theory in predicting the draft of a rubber tire loader’s bucket during initial penetration. The work uses 1:16 and 1:8 scale models of an 18-t capacity load haul dump, scaled with the Buckingham Pi theorem, to evaluate the prediction of draft and penetration under different operating and different dynamic conditions. We hypothesized that the observed relationships between draft and longitudinal penetration and the operating and dynamic conditions will hold true for an upscaled model. Similarly, we hypothesized that the results of experiments conducted with the smaller scale model should predict the draft on an upscaled model.

By M. B. Daza, B. Lattimer

"Even with modern detection and firefighting techniques, mine fires continue to be a safety concern. However, some underground mine fires can be addressed with the remote application of high expansion foam, reducing firefighter exposure to hazards. The flow of this foam can be numerically or computationally simulated in order to gain a better understanding of its behavior, but rheology parameters are needed as inputs to produce accurate simulations. For this reason, this work studies the rheology of firefighting high expansion foam using a foam generator and Poiseuille –Flow Rheometer. Rheological parameters for foams with expansion ratios between 250-1280 are represented by the consistency index (k) and the power law index (n) due to the results show a strong agreement with the Power Law model for non-Newtonian fluid viscosity. Furthermore, experimental results show that high expansion foam behaves as a shear thinning fluid with a power law index around 0.4 and viscosities in the range of s 0.1 Pa-s and 0.042 Pa-s under shear rates between 44 ??-1 and 187.3 ??-1. INTRODUCTION High expansion foams are called to foams with expansion ratio greater than 200. Expansion ratio (??) is defined as the ratio between the volume of foam produced (i.e. volume of foam solution and volume of gas) and the volume of foam solution used (NFPA 2014). Because of its high expansion ratio, one of the most important application of high expansion foams is to fill or flood large spaces such as hangars, storage facilities and underground mines for fire suppression. The foam can fill large structures using small quantities of foam solution within a short time (Sthamer 2012) (Martin 2012). Although the specific high expansion fire suppression mechanism has not been understood on a quantitative basis, a possible mechanism is fuel isolation when the foam act as a physical barrier between oxygen and the flame. Furthermore, as a consequence of this contact water is evaporated, causing cooling of fuel and surrounding air. Besides, water vapor as product of water evaporation causes a dilution of oxygen concentration available to the fire (Fleming and Sheinson 2012). High expansion foam can be applied remotely by means of conduit pipes or in situ close to the fire. In most of the underground mines scenarios, fires have to be addressed remotely to reduce miner and firefighter exposure to the hazards (Smith et al. 2005). Although high expansion foams should not be blasted and must be deposited directly on the area of application because of their low density (Harding et al. 2016) sometimes it is complicated to apply it directly to the fire due to complex access areas at underground mines. In these cases, foam has to be applied far away from the fire. Despite of this fact there is a lack of knowledge in terms of rheological behavior of high expansion foam under high shear rates (Gardiner, Dlugogorski, and Jameson 1998). Furthermore, there are a few attempts to simulate numerically the high expansion foam flow due to the ignorance of its rheological parameters and its complex behavior. (Weaire 2008)."

Jan 1, 2018

By J. K. Whyatt

In situ stress on the scale of a tunnel or mine may be distorted by geologic structures. The resulting variations of in situ stress have a direct bearing on the potential for mining-induced seismicity. New evidence from the Lucky Friday Mine collected by U.S. Bureau of Mines researchers, as well as a review of case studies, demonstrates that in situ stress variations affect the spatial distribution of mining-induced seismicity. Although overcore stress measurements have been useful in these studies, they are too expensive and, depending on conditions, may be too difficult, to use routinely in mapping stress variations. However, information from borehole and raisebore breakouts; deformation of mine openings; and patterns of seismicity, ground control problems, and rock burst damage can be used to build a stress database. This database can then be used in con-junction with maps of mine structure and geology and models of rock mass behavior to build a map of in situ stress variations. Such a map provides a means to anticipate patterns of mining-induced seismicity that are likely to be encountered and, hence, provide a means for planning appropriate measures to ameliorate rock-burst hazards.

Jan 1, 1995

By S. S. Sephton

Sintering as applied to agglomeration of ferrous fines has shown little growth in the United States in recent years. The general concensus was that most of the existing facilities would remain in production at a reduced tonnage to dispose of and recover solid waste from steel plants. Further growth for ferrous sintering technology was not in sight in the United States and in the early sixties expansion came to a virtual standstill, however, we witnessed a rapid emergence of a tremendous pelletizing industry. On other continents, due to different raw materials supply and capital structure, sintering technology continued to grow, with a more cautious development of pelletizing installations. In the U.S. the diminishing supply of good quality, high grade coarse ore resulted in eventual disappearance of high grade ore fines for sintering. The finely divided concentrates produced from lower grade ores were not amenable to this type of agglomeration, but were more suitable for pelletizing. Furthermore, pellets seemed to possess all the features of an ideal blast furnace feed; namely pellets are free flowing, uniform in size, strong, with extremely uniform chemical composition and good reducibility. Importance and demand for such well stabilized furnace feed further increased as size of newly installed blast furnaces continued to grow. The in- creasing demand for a uniform, stabilized burden coincided with the effort to produce a fully beneficiated burden for smelting, thus reverting the blast furnace to its primary function of smelting.

Jan 1, 1973

By L. John Minnick

Extraction of crude ores and minerals inevitably produces various by-products either as a result of nonusable residues or as waste by-products from process operations. Thus for each 100 tons of coal extracted in a strip mine operation, one can expect to produce 25 tons, or more, of mine refuse. In addition, the amount of ash produced from the burning of coal will represent 10 to 20 percent of the weight of coal burned. With the advent of lime/limestone scrubbers now being installed on many power plants, an additional by-product is produced that in most instances is equal in volume to the sluiced fly ash. Statistics developed by the National Ash Association have indicated that sluiced waste from power plants in the United States currently exceeds 25 million tons per year (dry basis). Overall mineral industry statistics (copper mines, etc.) indicate better than 200 million tons per year. In the past it was general practice to send most of these waste materials to holding ponds or lagoons simply as a means of disposal or "throwaway" of unwanted by-products. Unfortunately modern society has reached a stage where these large quantities of waste materials are creating monumental environmental and economic problems that need urgent attention. Among these problems are concern for loss of future usable land, pollution of ground water, loss of potential mineral reserves, and loss of opportunities to recycle or use these by-products for the benefit of future generations. An example of the latter is the serious shortages of construction quality aggregates that can be replaced with some of the by-products produced from waste materials from the extractive and chemical industries.

Jan 1, 1975

By Jan M. Mutmansky

Simulation is a general term which commonly appears in the technical literature and which can have different meanings to different people. One interesting definition (9)* applicable in an engineering context is the following: "Simulation is the use of a model to study a problem." In most cases, the model referred to in the above definition is a simulation model constructed in a computer language and implemented on a computer in order to solve the problem under consideration. The application of computer simulation models to the study of problems in materials handling and earthmoving has been successful in the past. Generally speaking, this method has been used where the system to be studied has many variables and where the ability to predict the outcome of the system under different sets of conditions is difficult. The prime reason for using such a model is to evaluate the numerous likely ways of operating any particular system without the necessity of actually conducting full-scale field tests. The simulation model presented here is such an application made to the process of tunneling and, in particular, to the process of tunneling with a boring-type tunneling device. At first glance, the process of tunneling may not appear to be particularly complex and susceptible to study by a computer model. However, a close analysis of the tunneling process will reveal that it is rather complicated as a result of limitations placed upon the system by restricted space in the tunnel, geologic variations along the tunnel

Jan 1, 1972

By Horst H. Gielen

Bong Mining Company/Liberia provides the rare opportunity to compare two generations of grate kiln pelletizing plants operating on the same magnetite/hematite ore basis. In this paper advantages and drawbacks are compared: mechanical aspects, energy-savings, pellet quality. Plant I with up- and down-draft drying gas flow. Plant II runs only on down draft drying and incorporates a heat-recoup system. Ferteco Mineracao/Brazil operates a Lurgi straight grate plant since 1977 on hematitic pelletfeed. Energy-political situation and char- coal as energy source in Brazil are reflected also in the search for alternative fuels for pelletizing. First measures and results are reported as well as intended further steps towards a 100 % oil replacement.

Jan 1, 1983

By Kent D. Gastreich

As the number of prime surface coal mining sites diminishes with time and with the potential for increased coal demand, areas that were previously not mined because of their difficult mining conditions, marginal economics, and controversial environmental nature, will have to be considered if surface coal mining is to continue in the future. Such sites include areas near major rivers, streams, and lakes. The name most commonly given to these areas by regulatory agencies is "wetlands". The exact definition(s) to the term "wetland" will be discussed later in this paper. Most coal operators are now more than familiar with permitting requirements under the Surface Mining Control and Reclamation Act of 1977 (SMCRA). The SMCRA permanent regulatory program recognizes the fact that coal mining operations will periodically encounter streams, wetlands, etc. Although discussed in various sections of the permanent program regulations, the relationship of coal mining operations to wetlands is particularly evident in the performance standards regarding hydrologic balance and protection of fish, wildlife and related environmental values.

Jan 1, 1980

By Yi-Hsuan Chen, Jürgen Brune, Candace S. J. Tsai, Alejandro Munoz, Connor Krause

This study highlights the significant presence of submicrometer- sized airborne particles in underground coal mines, especially around the belt conveyor drift areas. Using realtime instruments and gravimetric samplers, the assessment revealed that particle concentrations were notably higher in the belt entry compared to other locations, with a strong presence of submicrometer- and nanoparticle-sized dust. The study’s findings emphasize the importance of addressing small particle exposure, as these particles, composed of harmful substances like calcium, copper and iron, can pose serious health risks to miners. This research emphasizes the importance of improving air exposure estimation through more effective monitoring and characterization techniques to better understand and reduce workers’ exposure to hazardous airborne particles in the mining environments.

Apr 1, 2025