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By Xu Ronglie

This paper looks back on the developments and achievements of deep foundations, on the basis of the complex geological conditions and environments in China. It sums up advances in theoretical and applied researches, engineering constructions, practical experiences, case histories, and problems and developing prospects of piles and deep foundations in recent years in China.

Jan 1, 1991

By C. Dinis da Cama

In order to reduce the complexity of mechanisms influencing rock- fragmentation by blasting a simulation approach is proposed, using the capabilities of micro-computer interactive graphics. Situations involving cratering and bench blasting are simulated, and both jointed and intact rocks can be subjected to explosive action, taking into consideration its breakage mechanisms. Size analysis curves relating rock distribution before and after the blasts are determined and compared with field data.

Jan 1, 1984

By S Hu, P Ni, H Xu, P Chen

Indosinian (T) orogeny amalgamated the Mongolia-Xingan fold zone, the North China continent, the Yangtzi platform and the SE China fold zone into a unified continent. The early to middle Yanshanian (J-K1) orogeny created a Cordilleran type active continental margin in East Asia, reactivated the consolidated East China continent, and generated a large amount of granitoids, calc-alkaline volcanics and W, Sn, Mo, Cu, Au, and U ore deposits. The late Yanshanian (K2) orogeny began a transition to the western Pacific type continental margin. A tensional environment led to the development of peralkaline magmatism and tne formation of continental basins with red beds. The Himalayan (Tr-Q) orogeny was characterised by a backarc spreading and rifting regime. The dominant magmatism was continental basaltic.

Jan 1, 1995

By M. S. Prithvi

Over the decades, mine and mineral processing plant operations for the most part, have been found to have had adverse impacts on the environment. At the same time, mineral processing and mining operations produce mineral products that are indispensable to modern society. Thus, the sector has desirable and undesirable attributes simultaneously. The situation presents itself as a contradiction (i.e.) the mineral processing and mining operations are wanted by society, and at the same time unwanted by society. The existing methods of addressing the issues raised above have evidently not been very successful in reducing the opposition to new projects and to the related activities such as land acquisition. This paper attempts to show the relevance and applicability of TRIZ for addressing the issue. TRIZ, or Teoriya Rezheniya Isobretatelski Zadach, is a Russian acronym meaning Theory of Inventive Problem Solving. TRIZ is a powerful tool that can be usefully applied to resolve such contradictions, using resources usually available within the system of interest. Accordingly, this paper introduces the issue background, followed by an introduction to some key concepts of TRIZ such as the 40 principles, separation principles and directed evolution. The paper goes on to apply the 40 principles to two case studies. The results show that TRIZ could be a useful tool to generate potentially innovative and sustainable approaches. Its most appropriate position would be as a supplement to current decision-making procedures, and as a validation tool to review existing solutions for possible improvements. Keywords: minerals, environment, TRIZ, contradiction, resources

Sep 1, 2012

By R. V. Ramani

This report is volume 3 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation,' and ventilation. This volume of the final report describes the Methane Generator subsystem of the Master Design Simulator. This subsystem is used to determine methane emission rates into the mine environment. These flow rates are then used by the simulator in planning primary and secondary ventilation systems, planning a methane drainage system, and analyzing complex ventilation networks. Both steady state and unsteady state gas flows are included, and have been modeled as second order nonlinear partial differential equations. Finite difference equations are used to obtain numerical solutions to the models using a central differencing scheme. An application of the model is presented. The appendices include derivation of the gas flow equations used in the model as well as a users manual for the computer program.

Jan 1, 1974

By D. E. Calisaya, É. Poulin, A. Desbiens, R. del Villar, A. Riquelme

"A 15 cm diameter by 732 cm height, fully automated pilot column was installed in the Agnico-Eagle’s Laronde concentrator (Québec), for evaluating the performance of newly developed sensors and advanced process control algorithms. For eventual comparison purposes, the pilot column is continuously fed with the same slurry feeding the copper-circuit third cleaner column. It is equipped with electrical conductivity-based sensors for estimating the three variables used in the multi-variable control algorithm under evaluation: froth depth, fraction of wash water underneath the interface and gas hold-up. Froth depth is regulated using a PI controller while a predictive controller is formulated as the minimization of the tracking errors of gas hold-up and bias rate, keeping several operating constraints between their practical upper and lower limits. In particular, an unreachable high set point of gas hold-up can be selected in order to maximize the bubble surface area available for particle collection, while maintaining bias rate above a minimum value required for froth cleaning. The proposed strategy may indirectly help optimizing flotation column operation by using these secondary variables, without the implementation of a real-time optimization layer.INTRODUCTION Flotation columns have already been used for more than 30 years, mainly in cleaning stages, as a result of their froth washing capabilities. Despite their widespread usage, the measurement of some pertaining variables and their use for automatic control is rather scarce. Among the most important variables directly related to the process metallurgy (concentrate grade and recovery), froth depth (hf) is the only one normally monitored and controlled. Even though commercial sensors are available, gas hold-up (eg), a variable directly related to concentrate recovery, is seldom measured and never controlled. Another important variable, bias rate (Jb) responsible for concentrate cleaning, is simply not measured at all, as there is no commercial sensor available. Therefore, besides froth depth, continuous monitoring of process variables is limited to flow rates (gas, feed, tailings, wash water), i.e. to manipulated variables. Some new available sensors have been industrially tested, e.g. the Sonar-TracTM for eg (O'Keefe, Viega & Fernald, 2007) and the McGill hold-up sensor (Tavera & Escudero, 2002). Others, for bias rate and frother concentration, have been successfully validated at laboratory scale by Laval’s LOOP researchers (Maldonado, Desbiens, del Villar & Chirinos, 2008b; Maldonado, Desbiens, del Villar & Aguilera, 2010a). Some devices have been extensively used for monitoring bubble size and space distri-bution, e.g. McGill bubble viewer (Gomez & Finch, 2007) and others."

Jan 1, 2012

By Jesus P. Manzano

The report of which this paper is a summary was made in 1890 for the Compania Investigadora Mexicana y Americana. Since the region examined covers 900 sq. kilom., chiefly of wooded arid rocky hills, almost without roads, and for the most part uninhabited, While the examination had to be made in two months, of which period more than 15 days were continuously rainy, I need not say that this account is not complete and thorough. I. Geography and Topography. The center of this zone, 19 kilom. SW. of San Luis Potosi, is situated in lat. 21° 24' N., and long. 2° 3' W. of Mexico City. The altitude ranges from 1866 m. (that of San Luis) to . 2816 m. (that of the Realito mountain), in the Sierra de Sail Luis. The topography is hilly—partly wooded, partly bare. The principal more level areas are the Bledos valley on the south, and portions of the haciendas of Tepetates, San Fran cisco and Santiago, on the west. The water-supply is scanty. The two streams that cross the Zone, the Santiago and Bledos rivers, carry water nearly the year through, though much reduced in the dry season. Other streams are torrents of less importance. All the waters of the valley and Sierra of Sail Luis arc absorbed or sink, not passing beyond Soledad de los Ranchos. The Continental di vide is within the Zone, some waters going west to the Pacific, others east to the Gulf of Mexico. II. Geology. Concerning the geology of this district I condense the fol lowing from the memoir, Las Minas de Guanajuato, prepared for the Minister of Fomento by Senor Pedro Lopez Monroy, mining engineer, with which I am entirely in accord. He says, ill substance:

Jan 1, 1902

By Dale Bartholomae, David Harrison, Edward J. Walter

Methods that involve the use of signature blast holes in order to identify the particular frequency characteristics of a geographical area are widely available. Information acquired can be used to determine optimum blast hole timings to produce the desired constructive and destructive inference. However, these types of analyses can be both complicated and expensive. This study will investigate the use and practicality of signature hole and/or shift and sum analysis software and their application to small diameter construction utility blasting operations in Pennsylvania and faster moving projects in general. A determination will then be made as to whether this technology can be utilized by today’s blaster, from both a functional and a cost effective basis. Single hole blasts will be detonated on various smaller construction projects and will be monitored with an array of seismographs. The collected data will be analyzed in order to determine the optimum timing between holes to produce the preferred frequency content while keeping in mind the explosives user’s current inventory of blasting supplies.

Jan 1, 2005

By Corate L. Brierley

Low-grade porphyry copper ores containing chalcopyrite as the primary mineral was leached by two strains of acidophilic, thermophilic microbes belonging to the genus Sulfolobus. Leach tests were conducted in glass columns heated to 60-70° C. Pinto Valley and San Manuel ores sized to -1/2 inch + 50 mesh were effectively leached by the thermophilic organisms, but pinto Valley and Cyprus Bagdad ores sized to -2 inch + 1/2 inch resisted leaching. Aeration did not contribute measurably to bacterial copper extraction, since two columns, one inoculated and one sterilized, having a rest/ leach cycle without recurrent aeration exhibited copper extraction patterns similar to those of the aerated columns. Distilled water can be substituted for 9K medium without diminishing copper extraction. Decreasing the pH of the leachate to about 1.8 enhanced the extraction of copper from pinto Valley ore with the thermophilic microbes. Thiobacillus ferrooxidans was found to be relatively ineffective at copper extraction from pinto Valley ore. Of eleven solvent extraction reagents tested, Adogen 364 and Warsol at concentrations of 0.1% and 0.012 were inhibitory to oxygen uptake by the two Sulfolobus strains. Di-2-ethyhexyl phosphoric acid at concentrations of 0.1%, 0.01% and 0.001% were totally inhibitory to the respiration of both organisms.

Jan 1, 1979

By James C. Fowler

As report covers the installation and testing of a permanent seismic monitor system at the Loveridge Mine in West Virginia. The testing of the system showed several things: 1. Getting the seismic data hack to the central computer in a usable form is possible 2. It is possible to detect small explosions. 3. The use of this system as a auxiliary system to detect hammer blows from miners trapped in the area of one of the geophones is possible.

Jan 1, 1974

By N. Hanief

This research involves the investigation of phase transformations in the platinum-chromium coated system. Single-layer 0.1 µm platinum coatings were deposited via electron beam deposition on 99.98 percent pure chromium substrates. Specimens were subjected to systematic heat treatment in a vacuum furnace at 900°C for up to 20 hours. Phase formation and the changes in surface morphology were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM).Both CrPt and Cr3Pt phases are formed during heat treatment for different times at 900°C. Significant changes in the morphology of this coated system were detected after heat treatment at 900°C for 20 hours.

Jan 1, 2012

By C. J. Hall

I would like to congratulate Professor Gershon on an idea that is obviously valuable and is certainly new to me. It has, however, to be further developed, in that one can get fallacious results by limiting oneself to positional weights. In the example problem, the positional weight of one block was 8.6 (the 8.0 value in the paper was incorrect) for 36 units in the cone, for a mean block value of 0.239. The positional weight of the second block was 4.4 for 15 units, for a mean block value of 0.293. Surely one would expect the second block to be rated higher. Additionally, the time value of money adjustment cannot be determined by depth, because the time that a block is mined is determined by the mining sequence, not depth. Figure 1 shows a slightly altered version of Professor Gershon's pit. The overall value of the pit is the same, as are the total values under each of his blocks. The values in the right-hand cone have been reversed top to bottom, and the values in the rest of the pit adjusted to keep the central cone total unchanged. All values have been multiplied by 10. Figure 2 shows the sequence of mining, at three blocks per year, for Professor Gershon's pit, and Fig. 3, the sequence for a pit under the other block. Table 1 shows the value and discounted value (15%) of Professor Gershon's pit, and Table 2 shows similar values for the second pit. It is apparent that the second pit schedule is more valuable than the first.

Jan 1, 1988

The Physiographical Features of the Region The Middleback; Range proper, from the Iron Duke in the south to the Iron Prince in the north, extends in a meridional direction for 21 miles, but may well be taken to embrace also the Iron Knob and Iron Monarch prominences so that the total length of the Range is 37 miles.Although no great altitudes are reached, the slopes of the high country are steep and the Range stands out prominently above the peneplaned surface of upper Eyre Peninsula. The Range is built up of sub-parallel ridges at some places, and its continuity is interrupted by transverse breaks or gaps resulting from normal stream erosion and corrosion during earlier periods when precipitation was heavier and streams were more active. Traces of high-level gravels remain on the flanks of Kimba Gap. A former mature stream on the western side of the Range has had its lower reaches blocked by sand and the old stream channel has been converted into an eiongated basin of internal drainage. The sand dunes in this area appear to be practically stationary at present, being fixed by mallee vegetation. Their trend is west-northwest.The relief of the Range is regarded as having been determined primarily by meridional strike faulting and selective silification of some of the beds. Dip faulting on the Iron Duchess leases has produced subsidiary features only.The Rocks of the Region: In order that some of the points made in the discussion of the genesis of the ore bodies may be appreciated it is necessary to consider the stratigraphical succession and the igneous types represented. This classification may be...

Jan 1, 1949

By D Craw

Oceana Gold as part of their environmental strategy are looking at various methods for cost-effective revegetation of their tailings dams. Under the concept of revegetating the tailings this study looked at several issues. These issues were; testing different methods of revegetation, arsenic (As) uptake in vegetation with respect to capping thickness, and background As levels in farmland areas above mineralised rocks. A number of plots were set up in a temporarily disused tailings dam to trial the direct sowing of ryecorn into the tailings.   Ryecorn was sown in sandy tailings (ca 1000 mg/kg As) and then covered with oxidised schist to anchor the seeds. This proved successful and ryecorn was established. Once the plots covered with oxidised schist were growing, 1 m and 2 m strips were sown on the sheltered side of the existing plots without the covering of oxidised schist. The uncovered plots also established successfully. From this set of trials a sowing plan can be developed that uses a minimum of resources to successfully establish vegetation. The maximum As content of the ryecorn was 80 mg/kg. Clover, Yorkshire fog and ryegrass plant matter was sampled from a pot trial that used different thicknesses of topsoil covering tailings material. As the thickness of topsoil increased, the amount of As taken up decreased. Soil samples were taken from farmland areas which were known to have elevated levels of As (up to 1000 mg/kg) in the top 10 cm. Vegetation samples were also taken from the same locations, and show the As levels in plants is <50 mg/kg.

Jan 1, 2006

Multilevel-multiseam hardcoal mines on the European continent usually consist of a huge network of underground openings, sometimes more than 200 km long in total, with some longwalls operating down to a depth of 1,500 m. While operating several longwalls simultaneously, these mines are making use of a number of stationary and mobile measurement- and analysis units in their main ventilation passes combined with atmospheric measurements on the surface. This paper provides an overview over the systems and technology used and describes the typical set-up of a measuring net. To detect and monitor underground fires through fire gases measurement and -analysis, a mobile underground testing laboratory collects data locally in the area of the fire. These laboratories have proven to be extremely useful not only during the actual fire fighting but also for the long-term gas measurements in critical mine areas. They have repeatedly detected starting fires and have thus given the mine the opportunity to react early and to avoid larger damage. Therefore several mobile laboratory units have now been installed for long-term testing in a number of German mines and similar units are being used in the Czech Republic and Poland.

Jan 1, 2012

By Dunlop GA

Pilot Plant confirmatory testing of the treatment route developed in the Metallurgical Laboratory is an essential factor in the development of complex ore bodies. Objectives should be well defined to permit the efficient planning and cost effective operation of the pilot plant project. The primary objective for the pilot plant should be to confirm the viability of the developed flowsheet on a continuous basis, examining only major variables such as ore types, quantum changes in grind, comparison between bulk and sequential flotation circuits, use of flotation columns, evaluation of autogenous grinding and production of samples of concentrates for market evaluation. Secondary objectives may include the collection of engineering design data and the production of a comprehensive report to Bankable Document standards to provide technical support for capital financing. The complexity of the ore body and the scale of the final operating project together with the pilot plant objectives will determine the extent of the pilot plant operations. The level of expenditure associated with a pilot plant can vary, in total cost and as a percentage of the total development capital investment required to take the prospect from exploration to a producing mine. Factors contributing to expenditure are discussed. Associated with cost considerations is the level of confidence mining company investors can have that their capital investment will return dividends.

Jan 1, 1990

By G. L. Fitzpatrick

Preliminary results of an experiment in seismic holography indicate that the techniques of acoustical holography may be successfully used with seismic waves to determine the size and general shape of underground objects. This experiment was carried out under field conditions on a moderately large scale compared with the typical laboratory experiments in acoustical holography. The object to be mapped was a 100-foot-diameter, spherical, low-velocity zone of explosively fractured rock in oil shale at an average depth of 80 feet. The seismic wavelength of the Fourier component wave used in making the seismic holograms was 50 feet at a frequency of 140 cps. The hologram sampling aperture was 226 feet square and was sampled by 441 geophones in a 21 by 21 rectangular array. One novel aspect of the experiment was the use of a wide-band polychromatic explosive source of seismic waves rather than a narrow-band quasi-monochromatic vibrator source. A successful laser reconstruction of the object image from a lensless Fourier-transform hologram in the form of a 5/l6-inch-square photographic transparency is illustrated. The size of the underground object measured from the laser reconstruction of the object and the size inferred from a knowledge of the amount of explosives used to fracture the site and the tensile strength of the oil shale are found to agree.

Jan 1, 1972

By Dennis Van Heerden

Southern Africa has a long history of underground hard rock mining dating back to the late 1800?s. The rock support of underground excavations has significantly changed during this period, due to improved technology, experience gained and rock support requirements by mining and geotechnical engineers. This paper examines the available underground rock support methods in Southern Africa with emphasis on the types and characteristics of: - Rock bolt types. - Rock bolt and long anchor grouts. - Thin-sprayed liners. - Sprayed Concrete. - Ground consolidations through injection methods. - Cavity and void filling with aerated cement products. [ ]

Jan 1, 2007

By F. B. Kuhnow

When performing blasting operations in open pit settings, energy is released and transmitted through the geology. Some negative effects can have significant impacts on mining operations and adversely affect mine production. This technical paper presents recommendations for blast design to prevent damage due to ground motion from blasting on adjacent concrete structures of underground operations. The paper includes a case study describing a problem regarding an open pit mine expansion and asks whether production blasting will damage concrete shaft structures due to blast stress waves and blastinduced ground motion. Based on the results, a set of criteria is provided to implement in current and future mining operations that involve blasting near underground concrete structures. A set of techniques on how to improve vibration levels for safe operations is also presented. Knowledge of particle velocity and wave propagation for site-specific circumstances to determine a safe level of vibration is recommended. Emphasis is placed on making use of electronic detonators and early delay detonators to achieve successful levels of vibration. A dynamic analysis is necessary to determine if vibration from blasting can damage the concrete shaft structure. When reinforced concrete structures are subject to blast loading, both concrete and steel are subject to very high strain rates. As opposed to static loads, when subject to high strain rate loads these materials increase their strength significantly. In fact, they increase by more than 50% for reinforcing steel, by more than 100% for concrete in compression, and by more than 600% for concrete in tension. This finding is of significant importance in mining operations because it allows an increase in flexural capacity of individual members as a result of high strain rates. Therefore, an elevated ground vibration (PPV) or particle velocity is permissible when blasting takes place near concrete structures.

Jan 1, 2014

By Brendan Henry

The Canada Line is a 19km long automated light rapid transit system with 16 stations in Vancouver, BC, Canada. The Concession was awarded to InTransitBC to design, build, partially finance, operate, and maintain the system for 35 years. The project must be complete by November 2009 to be ready for the 2010 Winter Olympics to be held in Vancouver and Whistler, BC. The bored tunnel section consists of 2.45 km of twin bored tunnel and 3 stations. The station work is limited to the excavations and temporary support necessary to facilitate the bored tunnel works. A joint venture between SNC-Lavalin Constructors Pacific and SELI (SSJV) has recently completed the design and construction of this section. Work for the bored tunnel commenced in November 2005 with shoring and excavation works for the tunnelling operations pit that will become Olympic Village Station and will be completed in the spring of 2008. The tunnels were driven with a 6m diameter Earth Pressure Balance Tunnel Boring Machine (EPBM) and lined with 250mm thick, 5.3m diameter precast concrete segments. Seven hundred and fifty meters of each tunnel were driven through glacial and interglacial deposits of sand, silt, and clay with granitic boulders. The paper discusses the challenges faced in negotiating these soils which contained unforeseen geological conditions. These conditions were overcome by developing a systematic approach to Risk Management that included thorough risk assessments, regular risk management meetings with the participation of two of the world?s leading EPBM experts, Professor Eisenstein and Professor Kovári, and by the ability of the construction team to effectively analyze and mitigate problems.

Jan 1, 2008