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By JIACHENG XIE, XUEWEN WANG, QINGBAO BAO, ZEWEN YAN

The general application of memory cutting technology to shearers is improving the intelligence of the working face, but it has its limitations. It is only suitable for conditions where the environment of coal seam is changing slowly. It compensates for the cutting height by changing the fuselage attitude, and frequently adjusts the height to control the learning cutting trajectory, but due to the problems of shearer control and height adjustment accuracy, it cannot adapt to and compensate for the change of cutting height in a timely manner, resulting in poor cutting accuracy. This study puts forward a virtual memory cutting method based on prediction of the shape of the armored face conveyor (AFC). The integrated key technologies include generation of virtual teaching cutting curve, height adjustment strategy of front and rear drums, cutting

By C. L. Van Dover

Organisms living at hydrothermal vents are adapted to catastrophic disturbances in their environment caused by processes such as tectonic activity and mineralization that shift the locus of fluid flux and volcanic eruptions that pave over active systems and reset the hydrothermal cycle. The scientific community appreciates this risk of natural, local loss of species, genetic, and habitat diversity. The risks of more profound loss of diversity and ecosystem function and health as a consequence of additive commercial activities in hydrothermal systems are unknown, and are not the same across all deep-sea hydrothermal systems. Vent communities differ from one ocean basin to another, as do the geological settings and geochemical dynamics of vent systems. Communities on the East Pacific Rise represent one end-member in the catalog of hydrothermal vent communities. In these systems, the life cycle of a hydrothermal field is on approximately the same time scale as the lifespan of the species that live there. From studies of the 1991 and subsequent eruptions at 9N on the East Pacific Rise, we understand the rapidity with which new vents are colonized when nearby brood stocks are available to repopulate the system. Almost instantaneously, microbial biofilms and mats form, followed quickly by invasion of mobile opportunistic organisms (especially crabs, copepods). In a matter of a few months, a predictable succession of sessile organisms recruits, grows, and reproduces. Within two to three years, the system returns to levels of species diversity that begin to match those of the pre-eruption condition. Vents on the Mid-Atlantic Ridge (MAR) represent a different end-member, with catastrophic disturbance rare relative to the life span of the organisms that make up the bulk of the biomass. We have no experience with an eruptive event or other major transformation of venting activity on the MAR and thus have no knowledge or insight regarding the time it would take for the biological diversity to return to pre-cataclysmic levels.

Jan 1, 2008

By F. N. Siddiquie, Mohd Shaif, Rajiullah Khan, Juned Alam

Manganese ore bodies of Banswara Mn belt were classified into stratiform and stratabound types, based on their mode of occurrence, distribution, and their chemical characters. These ore bodies generally composed of braunite, pyrolusite, cryptomelane/ psilomelane, wad, etc. The stratiform-type Mn ore bodies are conformable with the associated host rocks (Mn phyllite, etc.) and occurred in the form of layers, bands, etc., which are variable in their shape and size. These ore bodies are also strongly folded with the enclosing host rocks. The others, which are stratabound-type Mn ore bodies, also showed an intimate association with the associated host rocks. These types of ore bodies occurred in thin layers, pockets, lenses, stringers, etc. The classified ore bodies are confined with Kalinjara formation of Aravalli Supergroup of Paleoproterozoic age. The ore bodies are structurally controlled and well associated with phyllite, schist, limestone, quartzite, etc. The stratiform-type ore bodies constitute a marginal to low Mn grade and are also characterized by lower Mn content (26.19–39.24%) along with the Mn/Fe ratio of 7.16–12.23, while the stratabound-type Mn ore bodies are rich in Mn (35.92–49.64%) along with the higher Mn/Fe ratio of 14.15–23.97. However, the poor Mn grade along with high siliceous impurities of Banswara Mn deposits is subjected to them for intermittent mining activities in the past and, consequently, did not attract the scientific and industrial community for the evaluation of these resources. Therefore, the authors attempted this study in a scientific and systematic manner (mode of occurrence/distribution and possible methods for evaluation/exploration) to evaluate the potential of existed and newer Mn deposit resources in the Banswara Mn belt. The whole findings would be very much helpful for exploration/ mining geologist along with other concerned, to completely evaluate these Mn deposits in the future.

Aug 16, 2021

By Staff

"In 2014, the estimated value of total mine production of nonfuel minerals in the United States increased. The quantity of production increased for most mineral commodities mined in the United States, as did prices. Notable exceptions were the declines in prices for most precious metals. Minerals remained fundamental to the U.S. economy, contributing to the real gross domestic product (GDP) at several levels, including mining, processing and manufacturing finished products. Following the reduction in construction activity associated with the 2008- 2009 recession that continued through 2011, the construction industry continued to expand in 2014, with increased production and consumption of cement, construction sand and gravel, crushed stone and gypsum, mineral commodities that are used almost exclusively in construction. Other segments of the nonfuel minerals industries increased as well. Trends in other sectors of the domestic economy were similar to those for industrial mineral production (Table 1).Discussion of mine production is frequently segmented according to the type of materials produced within the broad categories of metals and industrial minerals. Industrial minerals can be further subdivided as construction aggregates and other industrial minerals. The materials with the highest unit values, usually metals, tend to have very low production rates compared with those of many low-valued materials, such as crushed stone or construction sand and gravel. Therefore, for discussion and analysis of the performance of the minerals industry in general, the value of production is used rather than tonnage produced. Although the value of metals and industrial minerals mined in the United States are similar, if tonnages are compared, construction aggregates dominate, dwarfing the production of all other minerals combined.Mineral industry performanceThe estimated value of nonfuel mineral raw materials, including metals and industrial minerals, produced at mines in the United States in 2014 was $77.6 billion, a 3.5-percent increase from $75 billion in 2013 (Table 2). Net exports of mineral raw materials and old scrap were $15 billion (Fig. 2). Domestic raw materials, along with domestically recycled materials, were used to process mineral materials worth $697 billion. These mineral materials, including aluminum, brick, copper, fertilizers and steel, and net imports of processed materials (worth about $41 billion) were, in turn, consumed by downstream industries with a value added estimated to be $2,530 billion in 2014.In the United States in 2014, mine production of each of 14 mineral commodities was worth more than $1 billion. These were, in decreasing order of value, crushed stone, copper, gold, cement, construction sand and gravel, iron ore (shipped), industrial sand and gravel, molybdenum concentrates, phosphate rock, lime, salt, zinc, soda ash and clays (all types)."

Jan 1, 2014

By J. Best, K. Gallant

This paper explores the age-old concept of mine-mill reconciliation from a new perspective. Advances in reconciliation processes have been slow to materialize because in the quest for “rightness”, engineers, geologists and metallurgists have become entrenched in their viewpoints, dutifully performing to the metrics and expectations imposed upon them by the siloed organization. Moreover, reconciliation has not been viewed as a primary value creator, but an accounting non-value added task. In reality, the knowledge from reconciliation can significantly enhance yields. Critical review of the direct variables (tons, grade, etc.) and other less-obvious variables (incentives, communication, etc.) reveal a complex web of barriers to be cleared by management in order to realize benefits. Also, mineralogical reconciliation methods may offer renewed faith in the process.

Jan 1, 2004

By A. Anani

The goal of hot mix asphalt (HMA) design is optimal material blending to meet Superpave specifications. HMA cost minimization has being modeled as linear programing (LP) (Awuah-Offei et al 2011) and mixed integer LP problems (Brown et al, 2012) and solved with commercial software such as LINDO and CPLEX. Often these software, which are designed to solve general optimization problems, have licenses that cost thousands of dollars. The objective of this study is to develop a novel solution algorithm to the HMA optimization problem presented by Brown et al. (2012), which will negate the need for expensive commercial packages and is specific to this problem. This novel algorithm is based on the branch and bound algorithm for solving mixed integer problems. The algorithm is incorporated into a software package with an easy-to-use graphical user interface. The developed algorithm is validated using a real-life HMA problem. Using this solution algorithm will save companies thousands of dollars, otherwise used to purchase software licenses.

Feb 23, 2014

By Harvey W. Parker

Our industry has developed to the skilled, experienced and productive industry that we now enjoy as a result of the visions of great engineers throughout history, but, in particular for their visions in the last 1 centuries. Unfortunately for our forefathers, the technology lagged so far behind that these exceptional visions could not be realized for decades, sometimes for a century. All that has changed in recent time and many bold and visionary projects can now be constructed and operated because of dramatic advances in technology. Before, say, 1950, tunnel technology developed very slowly. However, technology is now developing at such a fast rate that planners and decision makers are challenged to stay ahead. Moreover, new technology will develop during the lifetime of any project that can dramatically improve under-ground space projects. One of the best examples of this technological advancement is that of closed-face TBMs which now make tunneling feasible in previously impossible ground conditions. Since it usually takes a decade or more to plan, overcome environmental and political issues, construct, and put into service major projects, planners and designers are challenged by the changes in technology that occurs during the long time span of planning and construction. This is particularly true of large infrastructure projects such as transportation, water and wastewater systems and other major underground schemes. Also, since the serviceable life of many of these tunnels is often over one century, planners must consider not only lessons learned from the past but also what new concepts and innovations may develop over an extremely long time. These and other issues create a great challenge to planners and illustrate the great importance of careful but creative vision and flexibility during planning of long-term tunnel and underground space projects.

Jan 1, 2008

By Jue Kou, Hongda Xu, Tichang Sun, Shichao Wu, Wenli Han

To investigate the effect of simultaneous change in particle size of raw materials (including ore, reductant, and dephosphorization agent) on the direct reduction process of high-phosphorus oolitic hematite, the experimental research of method with direct reduction and magnetic separation was conducted to investigate the effect of simultaneous change in particle size of raw materials on the final reduction products in the form of mineral composition, reduction speed, metallic iron particle morphology, phosphorus distribution, and powdery reduction iron. The results revealed that under the same conditions of reduction temperature, the raw material particle size affects the mineral composition of the final reduction product, the coarser the raw material particle size, the slower the reduction speed, the lower the metallization rate, and the larger the final metallic iron particle size formed. Under the same conditions of raw material particle size, the reduction temperature affects the mineral composition of the final reduction product, the higher the reduction temperature, the faster the reduction speed, the higher the metallization rate, and the larger the size of metallic iron particles within a certain reduction time. Neither the raw material particle size nor reduction temperature affects the form of phosphorus present in the reduction product. Both the raw material particle size and reduction temperature affect the grade of powdery reduction iron to a less extent, but affect the recovery rate and phosphorus content significantly. At the same reduction temperature, the recovery of powdery reduction iron and phosphorus content gradually decreases with the increase in raw material particle size. For the same raw material particle size, the recovery of powdery reduction iron gradually increases, and the phosphorus content gradually decreases with the increase in the reduction temperature. The results identified the effect of simultaneous changes in particle size of raw materials on the direct reduction process of high-phosphorus oolitic hematite and provide a basis for the selection of raw material particle size for the industrial application.

Dec 20, 2022

By F. J. Klingler, R. Hausmann, K. M. Swaffar, J. C. Neyer

This paper presents the results of a study of case histories of projects on which sinking caissons were used to construct shafts for tunnel construction and other underground works. Design methodologies are reviewed with respect to the impact of soil and groundwater conditions on the performance and constructability of sinking caissons. Factors which have led to success or failure are reviewed and evaluated, and recommendations for future investigation, design and construction activities are presented. Cost data for five recent projects are reviewed and compared to the cost of shaft installation by other means.

Jan 1, 1997

By Valerie (Wollet) Rebar

Successful execution of fast-track projects is an arduous task at best. Effective and organized management, a comprehensive technical design with an independent check-and-balance system, and optimal schedule components all play major roles in project success, regardless of the required timeline. However, a fast-track schedule intensifies the significance of each of these elements due to the heightened time constraints.

Jan 1, 2008

By Dean R. Gehring

Creating projects to reach a goal is not new to American industry. In fact, all major construction projects, from skyscrapers to bridges, are completed using similar project management techniques. However, modern project management is relatively new. It was not formalized until 1962, when NASA and the US Department of Defense recognized the need to develop uniform project management procedures throughout the aerospace industry (Moder, Phillips and Davis, 1983). This management method was not introduced to the mining industry until the early 1970s (Britton, 1983). Project management typically follows an organized, four-stage process —definition, planning, implementation and control.

Jan 1, 1996

By Y. Wang

Wet magnetic separation methods for recovering hematite and chromite fines and ultrafines are investigated in this paper. These methods include wet high intensity and high gradient magnetic separations, carrier or "piggy-back" magnetic method, magnetic field-induced aggregation and magnetic seeding. This investigation indicates that wet magnetic separation is more efficient for fines and ultrafines whereas other methods can be used to enhance the particle aggregation and/or the magnetic response. The magnetic behaviour of these minerals with respect to magnetizing field, particle size and temperature is also presented.

Jan 1, 1993

By H. M. Park

Risk is a major factor in all mining activities, arising from many internal and external variables. The authors? research has resulted in a systematic method for the quantification of risk in mining projects (Park, 2012). This is the second part of a three-part series. The first part was published in the October 2013 issue of Minining Engineering magazine and can be found here at www.me.smenet.org. This paper discusses methods of assessing the overall risk associated with those variables, and presents a statistical model based on a survey of 31 experts. The third paper, to be publised at www.me.smenet.org on Oct. 14, presents an evaluation of the statistical model, using data from previous mining investment decisions in which the authors have been involved.

Oct 1, 2013

By Earl Parker

The mining/mineral processing industry constantly faces the challenges of handling tons of material in a variety of processes such as crushing, milling, drying, belt transfer and loadout. These processes result in the production of high volumes of dust. A variety of dust detection and collection equipment is needed to properly manage these emissions to remain compliant with stringent air quality and safety requirements. Dust monitoring and bag leak detection can provide ways to reduce air pollutants, make work environments safer and remain compliant with requirements from the U.S. Environmental Protection Agency (EPA), U.S. Mine Safety and Health Administration (MSHA) and U.S. Occupational Safety and Health Administration (OSHA). There are several approaches to monitoring particulate emissions from dust collection equipment. These can include visual inspections, differential pressure gauges or bag leak detection systems. Bag leak detection and monitoring systems can be optical, light based or electrostatic/triboelectric. Recent developments have advanced the efficiency and reliability of electrostatic/triboelectric style monitors. New technological improvements have been developed that are based upon the principal of unifying dc (impaction) and ac (induction) signals and incorporating other proprietary circuit innovations. This higher signal resolution technology results in a more robust and stable measurement for detecting the presence of particulate in a dust collector emission duct or a flow process pipe.

By C. J. Greet

Grinding with an electrochemically inert grinding media (i.e., high chrome white iron) shifts the pulp potentials to more oxidising conditions, increases the dissolved oxygen content and reduces the EDTA extractable iron concentration when compared with milling with electrochemically active grinding media (forged steel). These changes in pulp chemistry produce cleaner particle surfaces, reduce reagent consumption, and increase concentrate grades and recoveries. This paper presents a robust laboratory test program that not only demonstrates the changes in the pulp chemistry, but also provide an indication of the magnitude of the metallurgical improvements that are possible. While laboratory studies are interesting, the proof is in the pudding! So, the paper provides an overview of plant trials conducted at several porphyry copper operations around the world: Newmont’s Cadia and Red Chris Operations, as well as Evolution Mining’s Northparkes Operation. These successful plant trials clearly demonstrate that selection of the right grinding media alloy will yield savings in grinding media consumption and reagent consumption as well as increases in revenue through improved copper and gold recoveries. However, many of the porphyry copper mines on the Eastern Pacific are copper-molybdenum deposits. The paper presents laboratory test results for typical copper-molybdenum operations and extrapolate these numbers to what might be expected should a plant trial occur.

Feb 1, 2025

By S. G. McDowell

This paper discusses the utilization of automation to increase productivity of continuous miners. Automation techniques are used during the design stage to decrease the time required and ensure the accuracy of the design. This is followed by automated manufacturing processes to reduce manufacturing time and improve the quality and consistency of parts. Combined, the result is a more reliable machine which can provide ongoing production capability. With the use of automation to enhance operator effectiveness and monitoring machine condition the productivity of machines is also improved.

Jan 1, 1991

By John E. Miller

Unit Rig & Equipment Co., manufacturer of Lectra Haul Trucks, is continually studying methods of reducing the operating costs of large haulage trucks. Reduction of haulage system operating costs is an important goal that equipment operators and equipment manufacturers constantly try to improve on. One of the most variable and important factors affecting operating costs is actual truck operating practices. An examination was centered on methods to optimize truck utilizaion. It was found that a very effective method of accomplishing this goal would be an Automatic Truck Control (ATC) system to automatically control a fleet of haulage trucks in a predetermined pattern. Economic studies were conducted which showed a very favorable reduction in mine operating costs by use of an ATC system. In 1970, Unit Rig & Equipment Company, in conjunction with SAAB-SCANIA began preliminary development of adapting for truck use a proven automated control system previously used for train systems, small trucks, and military target vehicles.

Jan 1, 1979

By E. Gutierrez, P. Gillies

Asset Maintenance Readiness (AMR) provides a tailored reliability and maintenance strategy specific to operational needs. AMR delivers reliability and maintenance foundations for the plant and equipment before start-up. Having a dependable reliability and maintenance strategy before start-up is critical, particularly in those first weeks and months during ramp up to stable production. The Asset Maintenance Readiness is the integration of Reliability and Maintenance Engineering analysis/studies at the earliest stages of the new Production System concept and design and during the Capital Project CapEx phases; adding this analysis to the Capital Project CAPEX cost, will have an impact of 2% to 3% of total project cost, but will deliver a good compendium of benefits far from the AMR costs, and those results will be shown upon commissioning and during the life cycle of the plant.

Mar 2, 2022

By W. Fletcher

Startup of a new plant is a very interesting time. It generally is also a very demanding and often frustrating period. Startup problems can become serious ii they impede the early achievement of full plant production. Raw materials are wasted, manpower is unproductive, field modifications can be extremely expensive and market commitments may not be met. This paper outlines a well proven and highly successful approach to eliminating many of the problems and frustrations often experienced in plant startup. The procedures and methods summarized in the following paragraphs have been developed over a period of 25 years during which some 90 plants were started up.

Jan 1, 1981

By Andrew Allan

[The Thompson Creek Coal and Coke Corporation, a. mall company engaged in producing coal in the Rocky Mountains of Colorado, is currently engaged in a struggle of destiny to increase their production from inclined seam operation to compete with highly mechanized horizontal bed mines. This paper introduces some of the problems encountered it pitch seam mining as they apply to the convention, room and pillar system employed at the present time. Further described is the test work now being conducted to overcome these obstacles with an. attendant increase in productivity. Included in this test work is a mining machine designed especially for pitching seams, an automated longwall, and hydraulic mining of the latter compared with those of conventional work presently employed.]

Jan 1, 1965