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By J. A. Finch

The metallurgical performance of a flotation cell is strongly influenced by the features of the bubble population, characterized by the gas dispersion properties, a collective term including bubble size, superficial gas velocity and gas holdup. It is required that gas be well distributed throughout the cell. Gas distribution is estimated here by simultaneous measurement of gas velocity (Jg) at different distances from the center (radial Jg mapping). This communication describes a technique to perform radial Jg mapping together with fundamentals for the interpretation of the data.

Jan 1, 2009

By R. W. Guill

"The Apex Mine is currently scheduled to be brought back into production by Hecla in the first quarter of1990. Its projected productivity rate will be exceptionally high for a small underhand cut and fill mine.The ore mined at the Apex Mine occurs within a pipe-like structure as a series of iron oxides containing both gallium and germanium, plus significant amounts of silver, zinc, lead, and copper.Ground conditions in and around the ore zone have dictated that unique approaches be utilized. To date, these have included a prototype 0.5 cu. yd diesel LHD, and the use of fibrous shotcrete in 4ft by 7ft headings, and the first pneumatically-placed cemented backfill in North America. Above all else, it is the combination of new technologies with a small and dedicated workforce which has allowed for the successful development of this ore body.IntroductionThe Apex Mine is an example of the typical small underground project. It has high grade, but low tonnage and is deposited in poor ground. In such cases, conventional planning and thinking generally results in an uneconomical evaluation and negative production decision. Fortunately, some unconventional thinking was allowed to take place during the planning and evolution of the Apex Mine development. The result now serves as an example of how such unconventional thinking can lead to the type of innovations described below.The job necessitated the development and use of new equipment and materials to execute a highly flexible underhand cut and fill mine design/pneumatic backfill concept, that must be constantly modified as different than assumed conditions become evident in and around the ore zone."

Jan 1, 1990

By H. Thomasson

THE war, like all destructive agencies, has focused attention on salvage and conservation, and to such an extent that a decade of normal progress has been crowded into a few months. This is particularly true as regards the repair of cutting tools. As a consequence, there has arisen a wide demand for comparable data by those engaged in such work, and for basic information by others who wish to repair tools. These repairs may be grouped in three classes: (1) The repair of broken tools of relatively slender cross-section, such as broaches, reamers, drills, etc., of a type that could be returned to service if a means to join the broken surfaces were available, as fortunately it is in the low-temperature silver solder process; (2) the repair of tools that possess shanks, tangs, and other non-cutting portions that may be broken or damaged to the extent that only the addition of metal will permit their return to service; and (3) the repair of special rotating tools, such as end-mills and milling cutters, that may have portions broken from the cutting edges or have their edges so worn in service as to require building up.

Jan 1, 1943

By A. K. Verma

This paper provides a brief overview of evolution of deformations, stresses, and pore pressures due to different excavation stages during construction of an URL. Excavation of a rockmass develops a damage zone of finite width around the excavated zone which is associated with changes in permeability and which affects the fluid flow mechanism. In this study, a coupled hydromechanical (HM) analysis has been conducted for a water saturated porous rock mass which has been created by sequential excavation and backfill of vertical disposal pit of an URL. For this purpose, an Atomic Energy of Canada Limited?s in-floor concept for a deep geologic repository suitable for Indian conditions has been used. Changes in rock deformations, stresses, strains and mechanically induced pore pressure in an undrained condition, during excavation, as well as those caused by mechanically induced rock deformations after backfill of the disposal pit, have been modeled. A three-dimensional finite difference tool FLAC3D has been used for the analysis.

Jun 1, 2012

By A. Torkian

Process water from production of concentrates in Meydook copper sulfide mine is transferred to the 8.3 million m3 tailings dam and a water retention pond after initial thickening. Elevated concentrations of heavy metals, sulfate, and TDS and decrease in pH as well as seepage into the aquifers have been the concern of the regulatory agencies since the start of activities. In this paper the results of a 6-month monitoring program from 4 wells are presented. The wells were located approximately 1.5 km from downstream of tailing dam (0.4 km from water retention pond) as well as upstream background well (2.28 km from water retention pond and 1.27 km from tailings dam). The objective was to study possible effect of accumulated tailings on the groundwater resources. Water levels in sampled wells were on average between 20 and 40 m. Results showed high levels of lead (5 ppb), copper (0.17-0.46 ppm) and selenium (73.1- 29.1 ppb). High levels of selenium and lead were partly due to natural geological settings of the area with high levels present in unaffected soils in the vicinity including water wells of villages upstream of mining operations. High copper levels were attributed to both mining operations as well as deposition from particulate air deposition onto the soil and transport to ground water by rain.

Aug 1, 2013

By G. M. Behrend

"AbstractMeasurement and control systems in minerals processing plants are usually well thought out and designed. The criteria and design parameters have been interpreted correctly.However, these systems often fail to perform satisfactorily or break down altogether as a result of in-plant conditions which are unpredictable and over which the instrument systems designer has no direct control. The foresight necessary to anticipate the problems and allow for them in the systems design can only be generated by experience.This paper lists the most common of these problems and offers practical methods for their solution. It then follows with an analysis of instrument installation practices and comments on special points that need watching.Finally, instrument maintenance is discussed with a view to achieving good maintenance at the best possible economy.Good MeasurementGeneralTHE MINES and mineral processing plants of the nineteen seventies, after decades of sensible caution, have now committed themselves to extensive automatic control. X-ray analyzers are freely specified. Sample acquisition systems are efficient and automated, computers are reliable and relatively cheap, and computer control systems in conjunction with the new analyzers are operating in a good many plants and are proving to be profitable.The sight of shift foremen and floor operators assembled in front of a TV-tube and taking a computer data display as gospel truth is quite common now, and yet was quite unthinkable only ten years ago."

Jan 1, 1977

By O. F. Carter

"Coniaurum Mines, Limited, hold nineteen claims in Tisdale township, in the Porcupine district, adjoining the McIntyre mine on the east. They extend for over a mile along the strike of the Hollinger-McIntyre 'break'. The property has been explored extensively along the ore zone both laterally and vertically. Workings have been carried to a depth of 5,500 feet, and nearly 50 miles of lateral workings (drifting and cross-cutting) have been driven to date in development and in gaining access to the orebodies.Production started at the Coniaurum in June 1928 and has continued without interruption. To the end of 1946 the plant has treated 2,695,725 tons of ore, yielding gold having a value of $21,989,918.The Coniaurum is controlled by Ventures Limited of Toronto. Mr. John Redington, who has guided all operations since work began on the property in 1922, is Managing Director.GENERAL GEOLOGYAge and Types of RocksKeweenawan- Quartz diabase dykes.Algoman - Quartz porphyry intrusive; the veins are probably late Algoman.Keewatin - Lava flows.Brief Description of Rock Types.Diabase DykesTwo quartz diabase dykes traverse the property in a north-south direction, cutting all formations, including veins.Porphyry IntrusivePetrographically all porphyries in the Coniaurum are of the usual Porcupine type- quartz-feldspar with alteration advanced in most instances to the stage where the feldspars are completely dissolved, leaving a wellsheared carbonate and sericite matrix with embedded rounded quartz 'eyes'. Alteration is most extensive in the smaller bodies and in the narrow protuberances from the larger masses; the cores of the larger masses are generally much fresher, with more or less well defined feldspar phenocrysts."

Jan 1, 1954

By A. Ghahreman, M. Oliazadeh

"Heap leaching is an attractive process for low grade deposits where the metal content of ore does not justify the high cost of milling and agitated leaching. In general, the heap leaching capital cost is low, construction is rapid, and production costs are low. The primary disadvantage of heap leaching is low recoveries (typically 65% of agitated leach recovery); thus, recovery improvements could convert more lower-grade deposits into minable reserves. This will also allow to process primary sulfide ores and result in a dramatic expansion of the technology, as ~80% of total ore types are sulfidic in nature. The old gold operations tailings are another massive source of low-grade gold material that can be retreated by the heap leach process. The major parameters affecting the recovery rates are ore characteristics (mineralogy, particles size of metal and host minerals, ore permeability), and operational conditions (segregation of ore, compaction, leach cycle time, lift height, and solution application rates). The design of a percolation leach process is based on a limited number of coarse ore bottle roll and/or column tests under ideal conditions. The economics of the projects and engineering design of the process facilities are developed based on the bench scale test work results and the application of the conventional engineering scale up factors. This paper will deal with the parameters affecting the HL efficiencies and focus on the potential improvement of gold heap leach recoveries. This would include design of heap leach operation and evaluation of processes such as fine crushing and bioleaching.INTRODUCTION Gold heap leaching is a hydrometallurgical process designed to treat amenable low-grade gold ores that contain typically 0.5 to 1.5 g/t gold (Marsden and House, 2006; Wong Wai Leong and Mujumdar, 2010). Ore is stacked by various types of equipment on an impermeable barrier, and a sodium cyanide solution is applied to the surface of the stacked ore. Gold, silver, and other metals contained in the ore are dissolved to various degrees by the cyanide application, as it percolates downward through the stack of the ore. The pregnant leach solution (PLS) is then collected at the bottom of the heap. The PLS is then sent to the gold recovery plant where the metals are extracted. The barren leach solution (BLS) is then reapplied to the top of the pad. Ore is placed on a pad or previously leached lift by various means, including ramp conveyor belts, radial-arm and self-leveling stackers, and trucks. Once trucks are used to construct the pads, the pad can be compacted and hence the pad should be graded and ripped or scarified (roughened up) with wheeled or tracked equipment to produce shallow cuts to increase surface area exposure to the leachate."

Jan 1, 2019

By M. L. Jeremic, G. J. P Delaire

"The mechanical aspects of cable bolt failure are considered from the point of view of properties of grout and cable, as well as of the rock in which it is anchored. The results from recent investigations made in-situ as well as in the lab are combined and presented with reference to other work done in the area. An attempt is made to stimulate the thinking along these lines so as to initiate further research which may enhance the design of cable bolting as it applied to mining operations.IntroductionIn the past twelve year s systematic cable bolting has found application in many areas. In civil engineering rock anchors have been used to provide tension at the heel of a dam permitting the reduction of its cross section. They have been used in retaining walls to reduce construction time and costs by eliminating the need for struts and braces which complicate pouring the foundation walls. It is also possible to use rock anchors in providing reactions where tall buildings are subjected to uplift on one side due to wind forces. Cantilever bridges may be constructed by implementing rock anchors to provide anchorage requirements. Anchorage piles or dolphins or mooring ships have also been built using these. In the mining area rock anchors, commonly known as cable bolts because they are made of hoist cable may be implemented in the reinforcement of hanging walls or to retain rock slopes.In order to sustain de-pressurized ground where rock separation developed along the pressure arches, cable bolts were utilized at the Tsumeb Mine in South-West Africa and also at the Strathcona Mine in Sudbury, Ontario, In both places old degreased hoist ropes were installed in downholes from crosscuts above a given stope and then grouted without tensioning. Jeremic and Cassidy described the use of cable bolts to increase hanging wall stability and postpone fracturing, in addition to producing pre-support for improvement of stope back stability."

Jan 1, 1983

By Ata Akcil, Z. B. Karshigina, Ye. G. Bochevskaya, Z. S. Abisheva

"Phosphorus slag is the most heavy-tonnage waste of yellow phosphorus production, which is stored in the dump fields for many years creating ecological problems in the regions. Despite of the actions taken to utilize the slags, most of them remain in the slag disposal area. One of the relevant and priority directions is rare-earth metals production (REMs), presence of which in the phosphorus slags allows considering the latter as an acceptable raw material source. Phosphorus slags contain about 30–40 wt% of silicon dioxide, therefore they can serve as a source of production of precipitated silicon dioxide highly required in different industries.The purpose of this work is the most complete REMs recovery in the solution while leaching and subsequent processing of siliceous cake. The work shows results of researches on establishment of the chemical and phase compositions of phosphorus slags, determination of the forms of presence therein of REMs compounds, processes of phosphorus slag leaching by nitric acid and processing of produced siliceous cake by NaOH solution.Based on the data of the instrumental and chemical methods of phosphorus slag analysis, it was established that it consists of pseudowollastonite a-CaSiO3 for 90–92%. It was found out that REMs are present in it in the form of carbonate apatite Ca10(PO4)6CO3 or rare earth apatite, and La2S3 compound inclusions.Optimum parameters of phosphorus slag leaching process were selected: HNO3 concentration 7- 7.5 mol/L; L/S ratio = 2.6–3 mL/g; temperature – 50–80o?; duration – 1 h; pulp stirring – 500 rpm. Recovery of SREMs, CaO, Al2O3 and Fe2O3 into the solution were achieved at 98.0, 99.1, 99.0 and 18.8%, respectively. Presence of 10 elements of the rare earths group in the phosphorus slag was established. It was found out that recovery of almost all REMs is within ~92–99%, except for Sc and Lu – ~39% and ~28%, respectively.For the purpose of optimization of siliceous cake leaching by NaOH solution, influence of some physical and chemical parameters was studied: N?O? concentration, L/S ratio, temperature, and duration. Results of the experimental data will serve as a basis for development of the technology of complex processing of the technological waste of phosphorus industry with production of REMs concentrate and precipitated silicon dioxide."

Jan 1, 2016

By D. Satish Kumar, D. Mazumdar

"95% bulk mixing times in three different size water model ladles of a 140 T cylindrical shaped , dual plug ( located diametrically opposite at mid bath radius position) stirred, industrial ladle were determined experimentally with and without an upper buoyant phase. Based on dimensional analysis and a regression of the experimental data and, it was shown that in the inertial and gravitational force dominated flow regimes, 95% bulk mixing times for a slag-less situation can be described via:[equation]Parallel to this, a large number of experiments were also carried out in one of the water models (D=0.30m) to quantify the influence of an upper buoyant phase on mixing. These indicated that mixing time, operating variables and thermo-physical properties of the upper phase liquid can be correlated via a dimensionless relationship of the type:[equation]in which, Q is the ambient gas flow rate, L is the depth of liquid , (AL) is the slag layer thickness and 6 and t are respectively the surface tension and viscosity of the upper phase fluid The dimensional analysis, regression of experimental data as well as the adequacy of the proposed correlations are discussed in the text."

Jan 1, 2004

Introduction A Hypothetical Scenario: Suppose that your company's research department has developed a new device which represents a significant innovation. You would like to begin selling it as soon as possible. The new device has not been publicly disclosed. You're not sure about what type of intellectual property protection you should be seeking, or when you should be seeking it. As discussed below, assuming that the costs are worth it, a patent application probably should be filed before any public disclosure is made. In general, if you do not file a patent application prior to a public disclosure, you will lose rights. Major Types of Intellectual Property In this paper, intellectual property protection is broadly discussed. Practical steps which can be taken to minimize the possibility of losing intellectual property rights (and maximizing the possibility of benefiting from your company's intellectual property) are outlined at the end of this paper. The issues discussed in this paper are somewhat complex, because a number of outcomes are possible, depending on the facts. It is strongly recommended that you seek legal advice in your jurisdiction in connection with any particular circumstances relating to intellectual property rights. "Intellectual property" refers to a number of different types of rights. The major types of intellectual property are: (i) patents; (ii) trademarks; and (iii) copyright. Trade secrets are also usually considered to be a type of intellectual property, and they are also discussed in this paper because of their importance. In general, each of these types of intellectual property protects different subject matter, although there can be some overlap. Intellectual property rights are generally territorial in nature. The scope of protection of a type of intellectual property in a country (e.g., patent protection) depends on whether the specific national requirements for protection have been met.

Feb 1, 2008

By Elbasher M. E. Ahmed, Indresan Govender

"A mechanistic model of axial charge segregation in rotating drums is presented. We show that granular material composed of different frictional properties diffuse into axial bands as a consequence of concentration fluctuations in the free surface layer that is caused by friction-limited mobility. A Bagnoldian stress assumption ensures an asymmetric free surface profile thereby providing the essential ingredients for the evolution of axial bands and the subsequent band coarsening observed in the literature. The formulation is sensitive to the boundary conditions of tumbling mills, including particle size and density, mill speed, inter-particle bulk friction, end wall friction and drum geometry (length and diameter).INTRODUCTIONA mechanism to fully describe the axial segregation of charge in a rotating drum remains elusive to the mineral processing industry. With regard to low aspect ratio mills (like ball mills), current thinking favours the use of closed circuit mills with correspondingly low residence times to offset the completely random contact probabilities between particles and balls (Wills & Napier-Munn, 2006). Conical end caps are argued to exploit the centrifugal force to achieve a regular gradation of ball size along the mill with larger sizes at the feed end and smaller ones closer to the discharge. However; segregation along the length has been observed in the absence of conical end caps (Oyama, 1939; Levine, 1999): In these investigations, sufficient differences in the particle’s mechanical properties (particle size, density, shape, surface roughness) was enough to successfully achieve axial segregation. Figure 1 shows the segregation of a bimodal distribution (by size) into bands of larger (darker colour) and smaller (lighter colour) particles."

Jan 1, 2016

By K. Esmaieli

ABSTRACT We conducted a series of numerical experiments to investigate the influence of rock mass foliation on impact-induced damage on ore pass walls. The 2D Particle Flow Code was used to simulate three distinct rock masses surrounding an ore pass, characterized by foliation angles of 60°, 90°, and 120° (clockwise from horizontal). Subsequently, we projected a rock fragment against the ore pass walls at a constant impact angle and velocity. The resulting damage increase

Jan 1, 2014

By G. Reuben Yourt

THIS paper is chiefly a description of the improvements in dust control chat have been brought about in the assay office grinding room at Wright-Hargreaves. The fume exhaust systems are briefly included because they also are important to the health of the employees. There are three chief factors which determine the efficiency of a dust control system: First, the amount of time and thought spent in designing it. Second, how close! y it is kept up to date with the growth of the plant-a system that is adequate for the number of machines operating when it is installed may fall short of fulfilling its purpose as the plant expands. Third, unless someone is held directly responsible, a system is likely to get out of repair and gradually lose its efficiency-this can easily be detected by regular dust surveys. In designing the present system at Wright-Hargreaves, the object kept in mind was to reduce the dust concentration of all operations to a safe limit, chat is, well under 300 particles per cubic centimecer of air. By doing this, a condition would be attained chat would make it possible to discontinue the use of respirators, which at best are not very comfortable and do not remove all of the hazardous fine-dust particles.

Jan 1, 1941

By H. Paudyal, K. Ohto, H. Kawakita, S. Alam, B. Pangeni

The orange waste after lime water modification was converted into promising adsorbents for fluoride by metal loading reaction. The effectiveness and mechanism of fluoride adsorption on metal loaded orange waste gel from synthetic and real plating solution were investigated. Amount of zirconium(IV), aluminium(III), cerium(III), lanthanum(III), titanium(IV), vanadium(IV) and tin(IV) loaded on orange waste from aquearegia dissolution were evaluated to be 1.62, 1.16, 0.93, 0.95, 1.20, 1.12, 0.97 mmol/g respectively. The maximum adsorption capacity (qmax) of zirconium(IV), cerium(III), lanthanum(III), iron(III) and aluminium(III) loaded orange waste for fluoride ions were evaluated to be 1.74, 0.91, 1.07, 0.98 and 1.01 mmol/g from aqueous solution. The mechanism of fluoride adsorption by metal loaded orange waste was inferred to be ligand exchange reaction. Application of zirconium(IV) loaded saponified orange juice residue(SOJR) for real plating solution showed effective removal of trace concentration of fluoride down to the accepted standard. The negligible interference of co existing anions like nitrate, carbonate, sulphate and chloride makes zirconium(IV) loaded SOJR a promising sorbent for waste water treatment. The adsorbed fluoride from fluoride loaded zirconium(IV)-SOJR was effectively desorbed by using alkali solution for its regeneration. This work shed light on the potential application of metal loaded SOJR to remediate fluoride contaminated water for environmental relevance.

Jan 1, 2012

By V. Shumila, T. Butler

Microseismic monitoring systems listen to a rockmass and record ground vibrations associated with brittle rock fracture. Modern systems record continuously and can identify as many as one thousand small and possibly larger magnitude events occurring each day from induced stress change and redistribution. This paper presents examples of the real time use of microseismic information in mining applications. It shows how alerts can quickly identify large magnitude events or unexpected clusters of seismicity and how seismic re-entry protocol can help to improve safety decisions. Additionally, newly developed advanced analysis techniques applied to mine seismic data sets are shown including the use of clustering methods to see into a cloud of seismic data to identify significant activity and quantify possible planar features. The use of source parameter trend analysis is shown to be a beneficial method for interpreting changes in relative stress levels. Seismic moment magnitude distributions are analyzed using the TGR (Truncated Gutenberg Richter) and TMD (Tapered Moment Distribution) methods to estimate bvalue and expected maximum magnitude. Seismic hazard analysis is shown as a useful way to simplify a dataset and highlight seismic hot spots. The rockmass response to excavation is a complicated spatial and temporal process and microseismic monitoring is a method that can be used to help understand the location and mechanics of failure occurring in the rock ultimately helping to improve safety and productivity at a mine site.

Jan 1, 2015

By W. E. Cockfield

This paper is not intended as an original contribution to this subject, but rather as a review of the main theories which are held with regard to placer deposits, with, of course, particular reference to the placers of British Columbia. The present interest in gold mining has, however, brought the subject of placers to the fore, and possibly a brief outline of the geology of such deposits will serve as a basis for discussion on the subject. In Canada, the most valuable of our placers are deposits of gold, and consequently the discussion will centre largely on placer-gold deposits. The same principles apply, of course, to placer deposits of other metals. The Origin of Placer Deposits As a starting point, the idea which is prevailingly held is that placer or alluvial gold is detrital in origin, that is to say, the gold originally existed in veins, lodes, or disseminations in the country rock of the regions in which the placer deposits are now found, and that, through the various erosive forces of nature, it was liberated from those veins or lodes and concentrated in the form in which we now find it. 1 have not time to go thoroughly into the proof of this, but the lines of evidence are many. If we take the Cariboo district as a typical example, Johnston and Uglow(l) have shown, first of all, that the placer and vein gold are identical in character. Crystals occur both in the placers and in the lodes, but the crystals in the placers are nearly always slightly worn, indicating transportation.

Jan 1, 1932

By R. B. Casault, J. D. Boyd, D. R. Bell

"Full-scale sections of three different types of Grade 483 line pipe have been evaluated extensively. The variations in chemical composition, optical microstructure, tensile properties, hardness and Charpy impact toughness with specimen orientation and location were determined. Significant variations in several properties, notably Charpy shelf energy, impact transition temperature, inclusion content and ferrite grain size, were observed for different locations in the pipes. The results indicate that current specifications call for test samples for the most conservative locations, except for impact tests. Minimum Charpy impact values generally occur at the II2-width location, which may be a more appropriate specified test location than the present I/4-width location. The anisotropy of impact toughness, and the importance of low sulphur content and inclusion shape control for adequate toughness in the transverse/rolling-direction orientation were demonstrated. The orientation of impact specimens is critical for spiral-weld pipe, and the current specification test is non-conservative in that it can give results which are two to three times higher than the minimum value for the steel.IntroductionThis report presents the results of an extensive metallurgical evaluation of three different Grade 483 line-pipe steels. The sample material came from full-scale sections of line pipe, which represented current commercial practice at the time of manufacture (1975-1977). Since then, significant improvements have been made in the manufacturers' procedures for producing skelp and pipe, and the line-pipe specifications have been revised. Hence, the information in this report is dated in terms of current design, but it is unique and significant in several respects:"

Jan 1, 1982

By Zhiye Zhao, Jianping Sun, Zhipeng Xu

"The subsea rock cavern project is an underground storage facility. For cost-effective and safe excavation, the risk caused by the groundwater seepage into the rock cavern must be addressed. As one of the essential steps of the assessment work, the hydraulic conductivities of the fractured rock masses should be reliably determined based on the limited measured data and geological information from the few boreholes. On the basis of site investigation data and monitored water flow and water pressure data during excavation, this paper presents an estimation method for hydraulic conductivities of the rock masses containing water bearing zones.INTRODUCTIONIn the development of underground rock caverns/tunnels, the uncertainty of hydro-geological conditions plays a critical role in terms of construction cost and construction safety. Excessive groundwater seepage has been identified as one of the key safety factors which always lead to vast loss, such as the Seikan Tunnel in Japan which encountered sudden water inflow and then catastrophic face collapsing, tunnel flood during excavation (Xu et al., 2013). As a key factor in the risk management associated with the groundwater leakage into rock cavern, the hydraulic conductivity determination is very important for cost estimation, reliable water control and construction management.The case presented in this paper is an underground project consisted of a cluster of rock caverns/tunnels for storage of hydrocarbon products. These caverns are located in heterogeneous sedimentary bedrock, at a depth of 130 m beneath a basin, and the crowns of caverns are located at about 100 m below the sea bottom. The caverns/tunnels are designed at two levels, the water curtain tunnels are at the upper level, and oil storage caverns are at the lower level, as shown in Figure 1. A number of horizontal and vertical water injection holes drilled from the upper water curtain gallery tunnel will establish continuous horizontal and vertical water curtains for providing a stable pressure distribution around the caverns, to keep oil/gas inside the lower storage caverns. As the hydrostatic pressure of groundwater around the storage caverns is higher than the pressure of stored oil and gas, the stored oil and gas will not leak out of the cavern (Lu, 2010; Xu et al., 2015). Groundwater pressure gauges are installed in the water curtain gallery tunnels, and water from the operational and access tunnels is injected continuously into the curtains to maintain the pressure. Some monitoring data are recorded at different construction stages. This paper proposes suitable methods to predict the hydraulic conductivity in rock mass and to determine the hydraulic conductivity in the water bearing zones."

Jan 1, 2015