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Because of its small interburden thickness, concentrated stress distributions, high coal seam metamorphism, and complex geological conditions, mining the five coal seams (Nos. 5, 7, 8, 9 and 12) of Kaiping coalfield is difficult. Kaiping coalfield is located within 80 m in the Kailuan Group. The overburden caving caused by mining the five coals seams was measured using ZTR12 geological penetration radar (GPR) survey combined with borehole observations. The development characteristics of full-cover rock fractures after mining were obtained from the GPR scan, which provides a measurement basis for the control of rock strata in close multiple-seam coal mining. For the first time, it was found that the overburden caving pattern shows a periodic triangular caved characteristic. Furthermore, it is proposed that an upright triangular collapsed rock pile and an inverted triangular area with larger fragments piled up alternately appear in the lower gob. The research results show that the roof structure formed in the gob area can support the key overlying strata, which is beneficial to ensure the integrity and stability of the upper coal seams in multiple-seam mining of close-coal seams.

Jan 7, 2020

By Gary Almeraris, Vincent Jr Tirolo

Traditionally, “Means and Methods” were the sole responsibility of Contractors. However, because of a number of litigious projects in the 1970s, Owners and their Engineers began including Suggested Methods of Construction (SMC) in Contract Drawings. By the late 1990s these SMCs were becoming baseline “Means and Methods” with Contractor recommended changes often considered as Value Engineering proposals. By 2004, the word “Suggested” was sometimes changed to “Prescriptive.” Owners are also purchasing TBMs and other mining equipment for Contractors prior to bid. Is limiting the contracting community’s innovation in developing their own “Means and Methods” and selecting their own equipment in the best interests of the Owner? Does it reduce the Owner’s, Engineer’s or the Contractor’s risk? Are claims reduced and finally what is the impact on the bid? A questionnaire was sent to more than fifty senior engineering field and management personnel representing more than 30 heavy construction companies to ask their opinion on these questions.

Jan 1, 2005

By Tim O’Neil

Upbeat, surprisingly so, might describe the mood at the2002 SME Annual Meeting and Exhibit in Phoenix, AZ. More than 4,000 mineral professionals gathered for three days of education, networking and product perusal. The Annual Meeting featured the theme, “Minerals for the Future@ SME” at the Feb. 25-27 gathering. Meeting attendance reached 4,039along with 479 exhibit booths show-casing 325 companies. Exhibitors found a good mix of industry types:37% from mining, 19% from processing, 20% from manufacturing and 28% from environment, education and government.

Jan 1, 2002

By M. Weatherspoon, S. Gebo, K. Prisbrey

Our objective was to develop a transfer function model of phosphate heap leaching for design, optimization and control. The procedure included analysis of time-lapse photography of a laboratory heap. Our experimental results confirm the predicted system transfer function kinetics. Our conclusion was that the transfer function and z transform that we have developed will allow us to control flow rate and pH online.

Jan 1, 2001

By Christopher J. Bambridge, Lee Seng Hoor

The Stormwater Management and Road Tunnel (SMART) Tunnel is a world first in the use of tunnel space transmitting both road and water through the same spatial envelope. The unique aspect of the SMART project is that the highway decks are used periodically for the conveyance of water. This aspect of the project has posed its own technical challenges that have been overcome in the design stage of the work allowing the project to be taken forward to construction with confidence in the systems to be Installed in the tunnel.

Jan 1, 2005

By Eduardo Pimenta de Melo, Rambabu Pothina, Rajive Ganguli

Sensors are everywhere in the mining industry, with sensor information being used to monitor and operate processes. Therefore, when sensor information is wrong, economic losses can occur. Unfortunately, sensor errors are usually not detected till they become large. This is problematic as most calibrate their sensors no more than once a year (Beamex, n.d.). Using principles of data mining, where all relevant information is tapped to glean hidden information, Pothina [8] designed an algorithm to detect errors in temperature sensors in gold stripping circuit in Pogo mine, Alaska. This paper continued his work by analyzing the behavior of the algorithm on baseline data and testing the algorithm in new data and under more rigorous conditions. It also made a change to the algorithm. The modified algorithm performed very well in the new data. It also worked well under the new error conditions. Three types of errors were seeded, a fixed additive error (+ 2%), a fixed subtractive error (− 2%), and a noisy, normally distributed error, with a mean value of + 2%. Artificially seeded errors were detected within about 20 gold stripping cycles. Inherent bias in operation impacted algorithm performance by increasing the number of cycles needed to detect errors. This paper reinforced Pothina’s [8] conclusion that when data mining approach is used, sensor errors can be detected even when they are pretty low. Significant economic losses can thus be minimized.

By J. A. Flinn

Phelps Dodge’s Morenci copper mine has had six drills, six track-dozers, 16 shovels, two loaders, and 90 haul trucks equipped with either Caterpillar, Aquila, or Modular GPS systems for nearly three years. The Caterpillar Computer-Aided Earthmoving System is an open-architecture system, which allows for inputs to enhance orientation solutions and system functionality. This system has begun a new phase that leads to an intelligent mining system. Optimization techniques of the current system and inputs are reviewed. In addition, some practical issues of implementing new technology in a mining environment have been identified to aid in this new phase.

Jan 1, 2000

By J. Reed

The RockWorks EarthApps represent a free collection of 74 geology-related programs that read data from a built-in datasheet and create diagrams within Google Earth. EarthApps also includes programs that extract data from Google Earth. The programs that create diagrams include: point mapping (e.g. borehole locations), proportionally scaled icons (e.g. geochemistry), and strike & dip symbols. Line mapping utilities include; polylines, parabolas and pipelines. Polygon mapping programs include; thematic mapping (e.g. geology), mining claims, and public land survey sections. Image overlay capabilities include; draping (e.g. geologic maps) and time-based animations. Vertical image display capabilities are centered on either midpoints (e.g. drill-hole logs) or stretched between endpoints (e.g. cross-sections). The Flyover programs create virtual tours for site presentations. The cell-mapping includes a variety of algorithms (e.g. geochemical and geophysical contouring). Survey programs convert and export survey data to Google Earth as points and polygons. Programs that extract data from Google Earth include; points, lineations, polylines, and polygons. The RockWorks/EarthApps collection is developed by RockWare Incorporated based in Golden, Colorado.

Feb 27, 2013

By A. K. Mukherjee

The roles of pulsating mechanisms such as the amplitude and frequency of the jig cycle are well established in jigging. Also well established are the roles of the size ratio and the volume fraction of the feed. In iron ore beneficiation plants, these process parameters are optimized to achieve the highest efficiency. However, the role of one of the more important feed characteristics, the liberation characteristic of the feed, has not been studied in detail. Evaluation of the liberation characteristics is difficult because the required washability test is not viable for iron ore feed. In this paper, a new method is proposed in which the liberation characteristics are measured through a separation efficiency value. In the new evaluation method, jigging parameters such as amplitude and frequency of the jig cycle are optimized from the fundamental understanding of the process dynamics and feed characteristics such as size distribution. Then, feeds with different liberation characteristics are tested to evaluate the liberation characteristics of feed in jigging.

Jan 1, 2008

By S. Jennings

The Red Dog zinc-lead-silver deposit is located in the DeLong Mountains of the western Brooks Range in northwest Alaska. The region is located 145 km(90 miles) north of the village of Kotzebue (Fig. 1).Red Dog’s current resource base is 143 Mt (157 million st) averaging 16.1% zinc, 4.3% lead and 83g/t (2.4 oz/st) silver. It is contained in four structurally separate deposits— the Hilltop, Main Deposit, Aqqaluk and the newly discovered Paalaaq deposit. Recent exploration for the Aqqaluk and the Paalaaq deposits has contributed to Cominco American’s understanding of the detailed structural geology of the district and its role in the placement of individual ore bodies.

Jan 1, 1999

By J. P. Kennedy, O. A. Bascur

Large metallurgical complexes have more data than a small city and these data change as internal and external conditions evolve. Staffing turnover hinders experienced-based decisions especially with simple tools like spreadsheets. Lack of current information can contribute to decisions that result in significant deterioration in the quality of operation. Timely, unified information from sophisticated analyses presented to the broadest possible reach will improve operation. The major innovation is the addition of the web browser to the suite of software people will use with no training – the other two are spreadsheets and graphical presentations – and the consistent organization and transformation of the real time data to support broad access. This paper describes the data transformations and presentation methods necessary for a Web view, especially the special needs of real time data and analysis required for active operations decision-making. Many people inside and outside the complex, not just operators, need timely information that is abstracted, aggregated, organized and unified. Unification and aggregation of real time data presented via the Web opens a new paradigm for collaboration. The analysis tools are as important as the data. These rule-based tools add significantly to the operations database in the form of results stored for viewing with plant data. Mining and metallurgical plants already use many sophisticated analysis tools such as predictive maintenance policies based on statistical analysis vibration analysis, and oil and lube analysis for critical equipment. These add real time events, similar to an alarm package, and unified production information to the operational database. Simple models are used on line to create key indices that provide a real time indication of performance. Key indices include metrics for losses due to plant availability, performance efficiency, and overall process equipment effectiveness. These additional data in the operations database are used for early fault detection, increased production, better quality, higher availability of equipment and faster detection of process bottlenecks. An important feature is the ability for people to create their own key indices and store the results for use by anyone in the plant historian, but accessible by a browser. Keywords: plant information, principle components analysis, data reconciliation, gross error estimation, Internet, Word Wide Web

Jan 1, 2002

By M. L. Harris

In underground mines, coal dust explosions are prevented by the addition of rock dust sufficient to render the coal dust inert. The National Institute for Occupational Safety and Health (NIOSH) developed a hand-held instrument that uses optical reflectance to measure the explosibility of a rock dust and coal dust mixture. This instrument is called the Coal Dust Explosibility Meter (CDEM). In this study, NIOSH personnel accompanied Mine Safety and Health Administration (MSHA) inspectors on their routine band surveys in five underground coal mines in MSHA District 2 (Pennsylvania) and three underground coal mines in MSHA District 11 (Alabama). While underground, NIOSH personnel and MSHA inspectors used the CDEM to assess the explosibilities of the dust samples. The values of percent incombustible content (percent IC) determined by the CDEM agreed well with those obtained later by low-temperature ashing (LTA) in both MSHA and NIOSH laboratories. Further, the meter identified some samples as potentially explosible that LTA analysis had found to possess sufficient rock dust for inerting. The CDEM provides more information on the hazards in the mine. Rapid identification of areas with explosible dust mixtures using the CDEM allows for immediate intervention rather than a wait of several weeks for laboratory analysis.

Jan 1, 2008

By Ivan Weber

Asking the question, “What do the world’s leading corporations and cutting-edge practitioners of sustainability put forth to guide a given mine site for planning and action toward ‘sustainability’?”, this paper explores the spectrum of methodologies and mindsets in available literature, then constructs an example for the large near-closure facility at Kennecott Utah Copper. Values, opportunities and constraints spring from physical, unutilized byproducts, from critical ecosystems and wildlife populations, from location relative to those ecosystems and proximate communities, and from the political will to perform adequate feasibility investigations. Patience, determination and thoroughness are imperative. Identifying most productive and, simultaneously, most protective and restorative, practical methods to approach ‘sustainability’ has become a central mission of industry and business, worldwide. A survey of recent international initiatives finds no single approach that establishes either a readily adaptable methodology or an appropriate set of ‘attention’ points, or agenda, to guide individual mining operations at specific locations toward the elusive but essential goal of ‘sustainable’ mining. Untying this convoluted knot of contending factors requires willingness to recognize and work within ecological constraints for community long-term needs. Occasionally, the task requires the sword of Alexander the Great. Through integration that is unflinchingly honest ethically, culturally, economically, ecologically and scientifically, fully cognizant of place and community at whatever scales are of greatest significance, and integrative of both problem-response and opportunity, we may envision a mineral extraction and beneficiation future that achieves the best, most nearly sustainable, results possible. Industrial ecology (IE), with its clear emphasis on community, ecosystems, and sustainable economic stimulation, presents a sufficiently broad and adaptable discipline to facilitate planning and management toward sustainable mining. The creation of sustainable jobs encapsulates IE’s analogy to the niche survival strategies of organisms in nature. Open to common-sense recognition of faults and opportunities at appropriate scales, IE is less a discipline or prescribed methodology than a mindset, willing to be rigorously scientific when science is imperative, but also willing to exercise “art” when creativity or community engagement are needed. IE is also capable of future-looking compassion for peoples and nature. Looking beyond what has occurred to date, the case of Kennecott Utah Copper provides ample illustration of possibilities for community economic development, environmental management, and significant initiatives beneficial at regional and planetary scales, to become recognizable as deserving of the label, ‘sustainable.’ Through what this researcher terms “whole mine, whole region, whole planet” thinking, strategies become visible and subject to serious consideration, presenting a path to best possible accomplishment in mining. Constituting a maximal broadening of mining’s “traditional” scope, the integrative approach proposed here is the ‘paradigm shift’ being made by many other industries around the world. In aggregate, these steps are the only hope for avoidance of environmental, social and economic risks that threaten to curtail resource development and impair mining companies’ ‘social license to operate.’

Jan 1, 2005

By Greg Sheppard, Eduardo Nebot

Australian researchers have developed new technologies aimed at improving safety and productivity at openpit mines. A data acquisition and feedback system for electric rope shovels has been shown to substantially reduce cycle times and decrease excessive machine duty caused by stalls. This data acquisition system was developed by the Cooperative Research Center for Mining Technology and Equipment (CMTE). It has been tested on a P&H 4100A shovel at Coal & Allied’s Hunter Valley operations and a P&H 4100XPB at BHP Billiton Mitsubishi Alliance’s Goonyella Riverside Mine in Central Queensland. In addition, CMTE member P&H Mine Pro Services has used the technology to acquire field data from a P&H 4100XPBrope shovel at RAG’s Belle Ayr Mine in Wyoming’s Powder River Basin.

Jan 1, 2002

By J. D. Miller, C. L. Lin

In the processing industries, it is well known that particle shape is an important factor which determines the behavior of particulate systems. For example, system properties of technological significance including rheology, suspension stability, agglomeration, packing, permeability…etc, are affected by particle shape. In this regard, characterization and analysis of particle shape is essential for more detailed understanding and improved development of particulate processes. In general, it is clear that the behavior of these systems depends on the statistical characteristics of particle shape. Remarkably few techniques exist to predict the mechanical and hydrodynamic behavior of an irregularly shaped particle or a population of irregularly shaped particles for that matter. The lack of models and correlations can be attributed to the wide variety and complexity of particle shapes, the difficulty of defining shape descriptors suitable for modeling, the limitations of measuring shape, and the lack of classifying techniques to characterize particle shape. In this paper, we present information on how 3D particle shape can be measured, characterized, and analyzed using cone-beam X-ray microtomography (XMT).

Jan 1, 2005

By Paul D. Klipfel

Introduction Mineral exploration interest, principally for gold, in the south-western Pacific has surged to new proportions. This is primarily due to the application of epithermal exploration concepts in the Australian-Oceana region. Other factors that have contributed to the high level of exploration interest include governmental policies supportive of mineral exploration, along with relative ease of tenure access and a relatively short bureaucratic process. This paper highlights exploration and development activities in the North Island of New Zealand, Fiji, Vanuatu, the Solomon Islands, and Papua New Guinea (Fig. 1). It provides a framework to understand the overall recent enthusiasm that has been brought to the south Pacific by explorationists. Through these recent developments, it is clear that the south Pacific region will become a significant gold producing area and thereby worthy of attention and study. Papua New Guinea alone is the free world's seventh largest producer (Table 1). And, with the addition of production from deposits presently being developed, this status is likely to be raised. History Gold was first noted on various Pacific islands in the late 1500s by Spanish explorers. They thought they had reached the legendary King Solomon mines. Since then, the history of prospecting in the southwest Pacific has coincided with the colonization of the region. Settlers in New Zealand extensively mined alluvial and lode gold deposits starting in the 1850s. The spread of European colonization to the more remote Pacific islands from 1880-1940 was accompanied by varying degrees of prospecting activity by planters, traders, and settlers. Some were successful, others may have been successful, but never returned due to hostile indigenous peoples or disease. In general, records of such prospecting activity are meager and exploration leads are, in some cases, gained through local village folk memory. Most early discoveries were alluvial finds. These led to placer operations, particularly in New Zealand, the Solomon Islands, and Papua New Guinea. Continued prospecting located lode deposits such as the Morobe Gold-field of Papua New Guinea, the Coromandel Peninsula of New Zealand, and the Emperor of Fiji. Some areas were prospected thoroughly. Yet others, such as Vanuatu, remained relatively unexplored until the present exploration surge began. During World War II, interest in minerals was diverted. It was renewed significantly until the middle 1960s and early 1970s when regional porphyry copper exploration was conducted.

Jan 10, 1987

By J. W. Jamieson, J. Escartin, A. Steinführer

Evidence of hydrothermal activity on two Mid-Atlantic Ridge oceanic core complexes (OCCs), at 13º30’N (the Semyenov 1 through 5 fields) and 13º20’N (the Irinovskoe field) (Fig. 1) were studied using CTD casts, dredges, TV-grabs and SP surveys during previous research cruises to these sites (Cherkashev et al., 2013, McLeod et al., 2009). In late 2013, the Semyenov and Irinovskoe fields were revisited, this time with an autonomous underwater vehicle (AUV) and a remotely-operated vehicle (ROV) during the ODEMAR (Oceanic Detachments at the Mid-Atlantic Ridge) cruise on the French research vessel "Pourqoui Pas ?". Here we present the first visual surveys and direct sampling of these vent sites. High-resolution (~2 m) bathymetry of the 13º30’N and 13º20’N OCCs and their associated vent fields was collected during 4 and 5 AUV dives, respectively, using the GEOMAR AUV "ABYSS" (Fig. 1). These surveys were flown between 70 m and 100 m above the seafloor, typically at a constant height to reduce vehicle movement. The AUV was equipped with Eh, turbidity, and temperature sensors in order to detect active hydrothermal venting. Over twenty ROV dives with the ROV "VICTOR 6000" allowed for the visual exploration of the OCCs and collection of 59 hydrothermal rock samples from the vent fields. As a result of these exploration activities, the first robust estimates of the size of the deposits, and the geologic controls on sulfide accumulation at these sites can be determined.

Sep 1, 2014

By A. L. Williamson, G. Savci

Hydrologic assessments of existing and proposed waste rock stockpiles (WRS) are typically required for application of operating and closure permits at mine sites. The results of these assessments can be used to determine the applicability of the state groundwater permit program requirements to the operation and closure of these stockpiles. The objective of this hydrologic assessment was to ascertain whether or not the WRS at the Ajo Mine have a reasonable probability of discharging potential pollutants to the underlying aquifer under the operational mine conditions. The hydrologic assessment was performed based on an evaluation of climatic data, prediction of the net infiltration rate through the WRS and prediction of additional hydrologic factors such as the time required to deplete available moisture storage in WRS. The predicted net infiltration rates ranging from 0.13 inches/year (1.1x10-8 cm/s) to 0.24 inches/year (1.9x10-8 cm/s) are below the threshold value of less than 10-7 cm/s recommended by Hutchison and Ellison (1992) as being characteristic of conditions that produce no or negligible quantities of seepage. In addition, the total time required to deplete available moisture storage within the Ajo Mine WRS and for any potential seepage from the WRS to reach the underlying aquifer is estimated to range from 260 years to 1,950 years. Collectively, the climatological and geotechnical investigations and the hydrologic predictions demonstrate that the WRS at the Ajo Mine hydrologically do not have a reasonable probability of discharging pollutants to the underlying aquifer. As a result of this prediction, the stockpile will not be regulated under the state groundwater permit program and operational and reclamation requirements will be limited to managing surface water runoff.

Jan 1, 2002

Recent expansion programs have made the Yunkang underground coal mine the number one producer in Shenxi Province. The mine is the newest in the Datong Coal Administration, currently rated at around 3 Mt/a of coal. Located in the Wa Chushi mountain range about 23 km north of the city of Datong, the mine has undergone a series of expansion phases since startup in 1973. Initial design capacity was 1.5 Mt/a and ultimately, production will be brought to an estimated 7.0 Mt/a by 1985, according to mine superintendent Li Jia-zhi. How Coal Occurs The coal, Jurassic in age, occurs in three economically identifiable seams designated No. 2, 3, and 7. Seams are 100-250 m below the surface. Reserves from this economic zone were not quantified, but Superintendent Li indicated that there was enough mapped out to sustain the expanded production rate for over 20 years. Below the Jurassic coal is another possible economic zone, a Permocarboniferous coal lying 400-600 m below the surface. Little development drilling has been conducted to ascertain its potential. The Jurassic beds are relatively flat and coal quality is reportedly one of the best in China. Heat content of the coal runs around 33.5 MJ/kg and the ash content is less than 10%. In some areas, it is less than 7%. Coal preparation is simple and involves a washing and screening separation into four principal size fractions. Washed coal is stored in one of six storage silos, each with 4000-t capacity. Mining the No. 2 Seam Since startup, primary production has been derived from the No. 2 seam. The coal is relatively hard and is topped by a hard cement-like conglomerate. These factors, coupled with an average thickness between 4 to 6 m, precluded the use of conventional longwall techniques, according to mine engineers. The solution was development of a room-and-pillar tech-

Jan 3, 1980

By M. Radwan, S. Shimada, S. Z. El-Tawil, K. A. El-Barawy, Y. Miyamoto

This study presents the results of synthesizing monolithic siliconoxynitride, Si2N2O, ceramic from a mixture composed of reclaimed silicon and natural desert sand by using the nitriding combustion synthesis method. Single-phase Si2N2O powder was prepared by the combustion of a mixture composed of silicon and pulverized sand in 3 MPa nitrogen gas. The combustion reaction completed in 2 min and the combustion temperature reached 1577°C.The as-synthesized Si2N2O powder is agglomerate of fine particles with sizes < 5 µm and has various morphologies; rod-like and irregular crystals, irregular kinking, hollow crystals and grown pseudo-hexagonal prismatic crystals. Porous Si2N2O compacts (24.5–47.1% porosities) were fabricated from the synthesized Si2N2O powder at different calcia-alumina additives (5–20 wt%) by normal sintering at 1500°C for 1 hr in N2atmosphere.They showed superior oxidation-resistance at high temperatures up to 1500°C in an oxidizing atmosphere of Ar/O2/H2O(70/20/10 kPa).Near-full dense Si2N2O compacts were also successfully fabricated from the synthesized Si2N2O powder with 5 wt% oxide additives by using the spark plasma sintering at 1600°C.DenseSi2N2O had good mechanical properties (18.7 GPa Vickers hardness, 3.3 MPa.m1/2fracture toughness and 363 MPa strength) and excellent chemical and oxidation resistance.

Jan 1, 2004