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By H. Kellerwessel

This paper refers to the new crushing and grinding process, which was invented by Professor Schönert (Ref.1), Clausthal, Germy (author of one of the papers presented at this meeting). The process is known as high pressure particle bed comminution or interparticle crushing. Several papers by Professor Schonert and his coworkers and by specialists of the companies producing the necessary equipment under license agreements already described fundamentals of the process, the equipment used, results of lab size and large scale tests and finally the first results of truly commercial operations (Ref .2 to 11). Therefore it should be sufficient to summarize the main facts here: - To a bed of bulk material a pressure of more than 50 MPa is applied. Comminution is achieved mainly by the pressure which one particle transfers to the other and not by squeezing single particles between the working surfaces of some crusher or grinding media.

Jan 1, 1987

By Monica Campos, Jose Mujica, Maria Campos

The extraction and processing of metals and other minerals have played an important role in economic, political, and social development worldwide, from the early stages of prehistory to the present day (Gosner, 2020). In other words, mining has been a fundamental part of human civilization, providing the raw materials necessary for technological, infrastructure, and industrial advances. As society progresses, the importance of mining continues to grow, supporting the development of everything from the smallest electronic devices to the tallest skyscrapers (The Importance Of Mining In Modern Society, 2024). The mining industry is closely linked to a country’s economy and activities related to natural resources. The economy of a nation is connected to its extractive industries (Moreira & McMahon, 2014), which have seen dramatic growth in recent years (Pietrobelli et al., 2018). In a context of increasing demand for natural resources, driven by the development of emerging technologies, the expansion of infrastructure, and the foundation of engineering achievements for the coming decades (Importance Of Mining - Minerals Education Coalition, 2024), mining should focus efforts on global development, requiring a comprehensive approach to sustainability that addresses the planet’s needs and protects the well-being, primarily, of the communities and environments where mining operations take place (Figari, 2024). In these areas, diversity and inclusion should be promoted, thus fostering equitable and sustainable development. Speaking of sustainable development, diversity, and inclusion brings us to an interesting topic: the Sustainable Development Goals (SDGs), also known as the Global Goals, which could serve as a key framework for fostering a strong social management culture in mining. The SDGs were adopted by the United Nations in 2015 as a universal call to end poverty, protect the planet, and ensure that all people enjoy peace and prosperity by 2030 (Sustainable Development Goals, n.d.). Companies have compelling reasons to align their actions with the SDGs, as their long-term success depends on healthy communities. This is a major challenge and requires collaborative efforts (Singh & Rahman, 2021). As Fraser (2021) mentions, achieving more sustainable outcomes may involve mining companies and communities working together collaboratively. This research proposes an innovative approach: Inclusive Mining for Sustainable Development, which aims not only to maximize economic profitability but also to promote social and environmental well-being by integrating the United Nations’ Sustainable Development Goals (SDGs), primarily focused on diversity and inclusion. This can be achieved through the implementation of a key value-added initiative for mining companies: the Creation and operation of a corporate volunteering program aimed at developing and executing inclusive practices to promote gender equality, the inclusion of local communities and indigenous peoples, and accessibility for people with disabilities. This proposal will educate employees and stakeholders about sustainability and promote concrete actions through corporate volunteering to strengthen the mining company’s commitment to community development, improve social relations, and advance toward achieving the United Nations’ Sustainable Development Goals, establishing the company as a global change agent.

Feb 1, 2025

Previous models describing the aggregation of polymer coated particles fail to take into account the fact that there are a limited number of sites onto which a polymer segment can adsorb, called ?active? sites. Thus, the collision efficiency is a factor not only of the fractional surface coverage, but also of the number of active sites. In this study, a physical model of the flocculation system was devised in which the number of these sites could be varied, in order to study the effect on particle aggregation.

Jan 1, 1987

By L. A. Roe

Calcium carbonate and talc fillers both find use in a multitude of Industries. Each filler has many commendable properties, and often compete for the same market. Quality controls for various grades are exacting and complicated. A detailed comparison of the physical and chemical properties of these two fillers is tabulated and the mining and processing of the ores is described.

Jan 1, 1980

By R. D. Williams

Several hydrometallurgical leach processes have been recently proposed for the recovery of copper from copper concentrates. These include the Cymet Process of Cypress Metallurgical Processes Corporation, the Arbiter Process of the Anaconda Company, and the Treadwell Process of Treadwell Engineering company(1). These processes and similar processes for recovery of other minerals, have several phenomenological similarities which make their quantitative description difficult at best. These include (a) the presence of more than one phase, (b) non-uniform mineralization of the feed concentrate, (c) surface and diffusional effects, and (d) a particle size distribution which varies with time. Semi-theoretical, rather than purely empirical, treatment of such processes in their developmental stages will result in a better understanding of the physico-chemical mechanisms in effect. This, in turn, will allow reliable process designs to be made on reasonable time scales for reasonable development costs. Once a production unit is built, such an approach will provide straightforward methods for process control and optimization. A research and development effort to determine criteria and procedures for semi- theoretically characterizing such mineral leach recovery processes has been initiated in a joint venture by the Arizona Bureau of Mines and the College of Mines at the University of Arizona. This group has as its task the mathematical characterization of hydrometallurgical leach recovery processes using semi- theoretical mechanisms for the underlying phenomena. The resulting models are experimentally verified and parameterized on the laboratory scale in such a way that they can be utilized with similarity criteria to provide reliable scaleup to production designs. This discussion will be centered around the elements of such an approach and how they fit together.

Jan 1, 1975

By YONGQIONG YANG, Ning Wang, CHONGGUANG LUO, LI ZHU, Hanjie Wen, SHENGJIANG DU, Hannian Gu

Niobium in kaolin clay from the Late Permian sequences was reported in the range of several hundreds of micrograms per gram and was considered as a potential resource for its high concentrations and large areal distribution. Ti-bearing minerals associated with kaolin clay were identified as the main host phase for niobium in some case studies. However, the correlation between the concentration of niobium and titanium is poor, and the types of Ti-bearing minerals and modes of occurrence of niobium are not clear. Typical kaolin clay samples from the Late Permian sequences from southwest China were characterized, and the final products derived from kaolin clay sample were investigated using XRF, ICP-MS, XRD, SEM, and TEM (EDS). The results reveal that there were three types of TiO2 mineral phases in the clay samples: (a) massive TiO2 minerals and (b) aggregates of nano TiO2 minerals did not contain niobium while (c) granular TiO2 minerals were the source of niobium from the EDS analysis. The granular TiO2 minerals included anatase and rutile, both of which were the sources of niobium in kaolin clay in the current study. The findings are of great theoretical implication for source and origin study of Ti-bearing minerals and guidance for separation and recovery of niobium from kaolin clay.

Nov 30, 2020

By A. Nieto

This article is a review of previous discussions about underground mining method selection and classification with the purpose to clearly define and classify the two groups of variables (indicators) involved in the mining selection process: key deposit indicators (KDIs) and key mining method indicators (KMIs). This paper provides a simple and clear approach for the classification and selection of a feasible underground mining method based on a predetermined set of favorable deposit characteristics, which are defined as key deposit indictors (KDIs). This article also gives a summary of the key advantages and disadvantages associated with every underground mining method based on their key mining indicators (KMIs). The selection method given in this paper is based on defining field KDIs and comparing them to the KDIs that are favorable to every considered mining method. By cross validating a matrix of favorable KDIs, the paper presents a simple approach to rank several underground mining methods using a scale from favorable to less favorable accordingly to the ore deposit characteristics (KDIs). KMIs are used to further complement KDI rankings by analyzing every method’s KMI performance based on the expected productivity of the mining operation being considered. To further assist the reader through the selection process, this paper gives basic sketches representing each of the primary underground mining methods discussed in this paper. Each method is given using the same 3D isometric view as spatial reference to assist the reader with visual interpretation and comparison between methods.

Jan 1, 2010

By N. Damiano, C. Zhou, B. Whisner, M. Reyes

"The industrial Internet of Things (IIoT)—a concept that combines sensor networks and control systems—has been employed in several industries to improve productivity and safety. NIOSH researchers are investigating IIoT applications to identify challenges of and potential solutions for transferability of IIoT from other industries to the mining industry. Specifically, NIOSH has reviewed existing sensors and communications network systems used in U.S. underground coal mines to determine whether they are capable of supporting IIoT systems. The results show that about 40% of the installed post-accident communication systems as of 2014 require minimal or no modification to support IIoT applications. NIOSH researchers also developed an IIoT monitoring and control prototype system based on low-cost microcontroller Wi-Fi boards, to detect a door opening on a refuge alternative, activate fans located inside the Pittsburgh Experimental Mine, and actuate an alarm beacon on the surface. The results of this feasibility study can be used to explore IIoT applications in underground coal mines based on existing communications and tracking infrastructure. INTRODUCTION The nation’s approach to health and safety in mining has historically been reactive in the sense that health and safety regulations and mandates have traditionally been passed as a result of tragic mining accidents. An example of this is the Mine Improvement and New Emergency Response Act (MINER Act) of 2006, which was passed as a result of several mining accidents where tracking of and communications with underground personnel were severely limited. While this reactive approach has led to the development and implementation of highly impactful safety interventions and safety practices, there currently exists a technological revolution that can shift the paradigm toward a proactive approach based on preventative methods: Internet of Things (IoT). IoT is the network of physical objects or ""things"" embedded with electronics, software, sensors, and connectivity to enable that network to achieve greater value and service by exchanging data with the manufacturer, operator, and/or other connected devices [1, 2]. It should be noted that IoT has been defined from various perspectives, and hence numerous definitions exist in the literature. The apparent ambiguity of the IoT definition might be due to the fact that IoT is syntactically composed of two terms: internet and things. The first one pushes towards a network-oriented vision, while the second tends to put the focus on generic objects. The traditional internet can be viewed as an internet of computers —i.e., “things” connected to the internet are computers only. IoT “extends” the internet by allowing other generic things that are commonly found in our daily life, such as refrigerators and cars, to be interconnected via the internet, and thus creates a bridge between the virtual word and the physical world."

Jan 1, 2017

By W. Z. Choi

In our previous work, a population balance model describing the simultaneous processes of size reduction and mineral liberation has been developed. The experimental verification of this model, however, has been limited to a binary mineral system containing only one composite particle class. When considering multiple classes of composite particles, the estimation of model parameters becomes much more difficult. In the present work, a procedure for estimating model parameters for a multiple composite class model has been developed. Emphasis is placed on the direct experimental determination of these parameters. The physical significance of the breakage rate function and the liberation function in characterizing the liberation process is also discussed.

Jan 1, 1987

By Erik Westman, BEN WESTON, SETAREH GHAYCHI AFROUZ, KATHRYN DEHN

This study investigates the changes in seismic velocity of rockmass before and after three major seismic events to determine any potential identifiable precursory velocity changes associated with these events. Induced stress measurement is one of the challenging tasks in deep underground mining, with extreme impacts on the safety and stability of the mine. This study used p-wave passive seismic tomography to image the velocity redistribution within a rockmass, which can indicate induced stress level changes in the rockmass and detect the velocity changes that might precede a major seismic event or a rockburst. The ultimate goal of this research focus is to develop another tool for the deep-mining community that will help to increase safety and efficiency. For this purpose, the hypothesis of conventional mechanics, which implies induced stress at the hypocenter (as inferred by the p-wave velocity) increases until the seismic event occurs, is evaluated. It is found that the p-wave velocity did not increase at any of the three hypocenters prior to the seismic event occurring; however, the p-wave velocity did increase in the closest “zone center” for two of the three events. 

By John Barber

The Deep Ore Zone (DOZ) Mine is PT Freeport Indonesia's (PTFI) newest operation. Production at the mine began in September 2000. The DOZ Mine produces 25 kt/d (27,500 stpd) using mechanized block cave mining methods. The DOZ Mine has several major improvements when compared with previous block cave mines in the district. It has an independent and improved ventilation system, a flexible and efficient truck haulage system, and a more reliable crushing and conveying system. PTFI's copper and gold mining complex is located in the Ertsberg mining district in Irian Jaya, Indonesia (Fig. 1). The Ertsberg district is located in the Sudirman Mountains at elevations from 3,000 to 4,500 m (9,800 to 14,700 ft) above sea level. The topography is extremely rugged and rainfall in the mine area averages 3,000 mm/a (118 in./year). Freeport began production in the district in 1972 when the mill began processing ore from the Ertsberg openpit. Underground mining began in 1980 when the Gunung Bijih Timur-Ertsberg East (GBT) Mine was brought online using block caving methods. In 1991, the GBT Mine reached a maximum production rate of 28 kt/d (31,000 stpd). Ore from the mine was exhausted in 1994. The Intermediate Ore Zone (IOZ) was brought into production in 1994. It, too, used block caving methods and had a design rate of 10 kt/d (11,000 stpd). The IOZ is currently producing at a rate of 21 kt/ d (23,000 stpd). The DOZ was discovered in the mid-1980s by deep drilling from the GBT. The GBT, IOZ and DOZ deposits are all situated in the Ertsberg East Skarn System (EESS). In 1993, the first of several studies was completed that indicated that portions of the DOZ Mine could be economically mined using block caving methods. Limited development was started in 1995. Full-scale development and construction began in late 1997. The crusher and conveying system began operating during the first quarter 2000. The first of two main exhaust shafts has been com¬missioned, along with three of the four new main fans. The second exhaust shaft and fourth main fan will be in service by the end of 2001. Undercutting and production began in September 2000. The DOZ Mine will reach its design production rate of 25 kt/d (27,500 stpd) in 2003. A study is under way to determine if an ultimate production rate of 35 kt/d (38,500 stpd) is feasible.

Jan 1, 2001

By Ali Jaberi Zamharir, Abolfazl Shoghian‐Alanaghi, Hossein Aghajani, Arvin Taghizadeh Tabrizi

In this study, the leaching rate of molybdenite concentrate was evaluated in sulfuric medium, and the influence of the diverse oxidants including hydrogen peroxide, manganese oxide, copper sulfate on the leaching rate was studied. Also, the effect of the addition of the ethylene glycol to the hydrogen peroxide was studied and results showed that with the addition of ethylene glycol, the leaching rate is increased 55% from 41% up to 80.3%. The optimum condition is achieved as 0.7 M of H2SO4, 4.4 M of H2O2, and 3.5 M of EG at 30 °C within 4 h of leaching time and 500 rpm. Also, inserting the oxygen with the pressure of 6 bar to the leaching autoclave, the leaching rate is increased more up to 86.4%. Finally, the leaching process was studied kinetically and the determined mode of controlling factor was specified based on the activation energy which equals 46.252 kJ/mole indicating the chemical reaction mode.

Jun 5, 2022

By M. R. Shahan, C. E. Seaman, S. E. Mischler, T. W. Beck

"Float coal dust is produced by various mining methods, carried by ventilating air and deposited on the floor, roof, and ribs of mine airways. If deposited float dust is re-entrained during a methane explosion, without sufficient inert rock dust quantities, this float coal dust can propagate an explosion throughout mining entries. Consequently, controlling float coal dust is of critical interest to mining operations. Rock dusting—adding inert material to airway surfaces—is the main control technique currently utilized by the coal mining industry to reduce the float coal dust explosion hazard. To assist the industry in reducing this hazard, NIOSH’s Pittsburgh Mining Research Division (PMRD) initiated a project to investigate methods and technologies to reduce float coal dust in underground coal mines through prevention, capture, and suppression prior to deposition. Field characterization studies were performed to determine quantitatively the sources, types, and amounts of dust produced during various coal mining processes. The operations chosen for study were a continuous miner section, a longwall section, and a coal handling facility. For each of these operations, the primary dust sources were confirmed to be the continuous mining machine, longwall shearer, and conveyor belt transfer points, respectively. Respirable and total airborne float dust samples were collected and analyzed for each operation and the ratio of total airborne float coal dust to respirable dust was calculated. During the continuous mining process, the ratio of total airborne float coal dust to respirable dust ranged from 10.3 to 13.8. The ratios measured on the longwall face were between 18.5 and 21.5. The total airborne float coal dust to respirable dust ratio observed during belt transport ranged between 7.5 and 21.8. INTRODUCTION During the extraction of coal, various dusts are produced that can be classified into two categories of interest: respirable and float coal dust. Respirable dust (diameter 10.0 = µm) has the capability to penetrate beyond the terminal bronchioles and become deeply embedded into the human lungs, leading towards respiratory disease complications (Potts et al., 1990). Float coal dust is defined as coal dust having a diameter less than 74 µm (Harris et al., 2009). During the mining process, float coal dust can be deposited on the floor, roof, and ribs of mine airways. With the proper mixture of methane gas (between 5% and 15%) and an ignition source, a methane gas explosion can occur (Barker and Humphreys, 1996). The resulting explosion can develop a pressure wave which lifts the deposited float coal dust material into the air, propagating a disastrous coal mine explosion (Harris et al., 2010). The current technique to safeguard against the propagation of a coal mine explosion is to treat the mine airways with incombustible rock dust (typically limestone), maintaining an 80% total incombustible content of the deposited material. NIOSH initiated a project to investigate control technologies that could be aimed at reducing the amount of float coal dust allowed to deposit in the mine airways using three approaches: prevention, capture, and suppression prior to deposition. Reducing the float coal dust being generated during the mining processes and capturing or suppressing airborne float coal dust prior to deposition would in turn increase the efficiency of the applied rock dust used to prevent mine explosions."

Jan 1, 2017

By Brian Y. Lattimer, Kray D. Luxbacher, Jonathan L. Hodges, Manuel J. Barros-Daza

The abstract discusses the importance of predicting fire response time (the time before conditions become untenable for firefighters) in underground coal mines. It introduces a data-driven approach using artificial neural networks (ANNs) to predict response time and fire size based on measurable parameters like CO concentration, mine geometry, air velocity, and time since fire detection. The approach was tested using simulations from fire models (FDS and FSSIM), showing promising results for real-time predictions during mine fires.

Mar 6, 2022

By Michael J. Friedel

The permeability and flow capacity in unsaturated media is investigated by the Bureau of Mines for application to in situ copper leach mining at the Cyprus Casa Grande mine site. Moisture retention properties are derived and combined with scanning electron microprobe data to characterize the mineralogy, texture, pore size, distribution, and permeability of the host rock. Finite element modeling is used to derive a saturated permeability, ambient degree of saturation, and assess various injection-recovery schemes. Recommended design modifications for optimization of solution distribution and maximum recovery from the rock matrix requires either (1) the injection pressures on the order of 1500 psi and recovery wells operating in a suction mode, or (2) performing permeability enhancement, through rubblization. By producing a maximum block diameter of 4 m, injection pressures can be reduced to 500 psi with improved recovery and containment of solutions.

Jan 1, 1991

By Sahin Furkan Sahiner, Onur Golbasi

Effective maintenance planning is vital for coal mining operations, where haul truck fleets directly determine production continuity. This study presents a discrete event simulation (DES) model for evaluating maintenance strategies under multiple failure modes and their interdependencies. The model integrates corrective, periodic preventive, and opportunistic maintenance, dynamically updating equipment lifetimes through probabilistic time-betweenfailure and time-to-repair distributions. Applied to a fivetruck coal haulage fleet over a one-year horizon, results show that periodic preventive maintenance delivers the highest availability (76%) under unconstrained conditions, slightly outperforming corrective-only maintenance (75%). Opportunistic and integrated approaches performed worse (68% and 69%), reflecting redundancy from overlapping interventions. These findings suggest that structured preventive programs provide the most reliable outcomes when costs and resources are not limiting. The DES framework serves as a baseline for future models incorporating cost, spare parts logistics, and workforce availability, supporting robust maintenance planning in coal mining operations.

Feb 22, 2026

By Felicia F. Peng

The manganese removal from aqueous solution containing high Mn2+ concentration by adsorption and oxidation was studied using manganese oxide particles as the adsorbent. The operating parameters including pH, flow rate, initial manganese concentrations, and oxidant dosage affect the performance of Mn2+ removal were evaluated in a laboratory packed column. In the multi-column adsorption tests, each additional column doubled the time for complete manganese removal. No further decrease of pH was also observed once it was lowered to pH 4.5 to 5. This finding implied the possibility of complete high manganese removal without further pH adjustment during adsorption. Oxidation of Mn2+ by dissolved oxygen was found to be insignificant for manganese removal for high Mn2+ concentration. Adsorption was the predominated mechanism involved with manganese removal. Extremely low H+/Mn2+ stoichiometry compared to the reported values was measured. These low values suggested that different adsorption mechanisms such as chemisorption other than H+/Mn2+ ion exchange might play an important role at low pH. This paper presents the quantity and explanation of the results obtained for the mechanism of adsorption and oxidation of high concentration manganese on the manganese ore particles.

Jan 1, 1997

By R. E. Nelson

The Alton Coal project, located in south-central Utah, lies at one point just over six miles from Bryce Canyon National Park. This region of the southwestern United States has been called the "Golden Circle" of national parks and monuments. Can a mine be inserted into this region so that it does not intrude on this spectacular landscape? The Alton Coal Project is a proposed surface coal mine designed to serve as the fuel source for the Harry Allen Power Plant, a 1,000 megawatt generating station planned for a site 25 miles northeast of Las Vegas, Nevada. The mine and the power plant will be connected by an underground pipeline through which coal will be transported in slurry form.

Jan 1, 1988

By Yashar Pourrahimian, Magreth S. Dotto

Fragmentation by blasting is a critical process in hard rock mining. The blasting process and outcomes are highly influenced by rock mass properties and their response to higher stresses and loading rates. Each rock mass is unique, but some features affect the blast energy similarly, leading to similar outcomes. Having analyzed these features and their influence on blast results, they can be incorporated into the blast design to achieve better outcomes. This paper presents a numerical model validated by a case study from the actual mine blasts that studied the effect of rock mass properties on explosive energy production, attenuations, and overall blast outcomes. The results show that when the model parameters are calibrated based on real data, they can be used to simulate the fragmentation process and therefore be used to aid blast design.

Jun 25, 2023

Automation and robotics are the keys to new intelligent autonomous mining systems which can remove operators from the hazardous and stressful mining environment and provide the tools for greater productivity. This pa-per presents the components necessary for a mining Intelligent Task Control System (ITCS) in dynamic unstructured mining environments. The proposed concept is applied to develop the ITCS for an autonomous excavator. The design and implementation of a fuzzy logic controller for an excavator that uses force/torque sensor feedback to complete excavation tasks is presented. Initial experimental results are also given.

Jan 1, 1994