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By Murad Y. Abu-Farsakh

This paper presents the analyses of load-transfer (t-z) behavior of twelve prestressed concrete (PSC) instrumented test piles that were driven in different locations of Louisiana. The load transfer method is an efficient and practical tool for the analysis of single driven pile to predict the ultimate load. The test piles were instrumented with vibrating wire strain gauges in order to calculate the shear transfer for different soil layers during the static load test. The static load test was performed on all the test piles after 10 to 14 days of end of driving. Empirical load-transfer models were proposed previously by different researchers (Fleming 1992, Hirayama 1990, Krasinski 2012, Bohn et al. 2017) after analyzing the instrumented test pile results. For this study, load transfer of each soil layer was measured and compared with the previously developed existing model. The stiffness parameter (M) for the hyperbolic equation was calibrated in order to best match the measurements. The good agreement of the proposed curves was then confirmed by applying them to assess the overall load-settlement curve of other pile load test results available in the literature. INTRODUCTION The load transfer mechanism (stress-strain relationship) for an axially loaded pile usually comprises of three loading mechanisms: axial deformation in the pile (z), soil skin friction along the shaft (qs), and soil end-bearing (qb). The development of soil skin friction with axial deformation is referred as the t-z curve, and the development of soil end-bearing with axial deformation is referred as the q-z curve. Figure 1 presents the load transfer mechanisms in an axially loaded pile and the corresponding spring mass models for t-z and q-z curves (API, 2002). In order to construct the load transfer curve in clay under vertical load, the axial load transfer (t-z) curve and end-bearing load transfer (q-z) for that particular soil should be assessed separately. The axial load transfer (t-z) method is probably the most widely used technique to study the problem of single axially loaded piles. Therefore, the load transfer through the shaft of the pile and are getting more and more important compared to the only the pile capacity analyses. The load transferred from shaft to the surrounding clay soil is a function of the width of the pile and the surface roughness of the pile and clay properties. The development of a representative procedure allows the assessment of the t-z curve in soil (sand and/or clay) that leads to the prediction of a nonlinear vertical load-settlement response at the pile head.

Jan 1, 2018

By O. Ogunsola, M. Downing

This paper gives a brief overview of impacts of coal blending on coal-fired power plants performance and discuses the preliminary results of an on-going study aimed at evaluating the effect of coal properties on the effectiveness, compatibility and thermal reactivity of coal blends. Plant survey studies reported no significant impacts on an existing plant designed for a high rank coal when switched to a blend of low- and high- rank coal. However, slight modification of some aspects (handling, fuel storage/stockpile, transportation, preparation, and general housekeeping) of plant design and operation may be necessary. The preliminary results of an on-going study at the Mineral Industry Research Laboratory shows that more compatible and better blends could be made from coals where ranks are closer than from those where ranks are far apart.

Feb 24, 1997

Exerting the Advantages of National Key Discipline, Outstanding the Training of Engineering Capability, Cultivating Talent to be with Innovation Ability

Sep 13, 2010

By Pierre Lacoste-Bouchet, Ian Orford, Mike Cooper

"The Brunswick Mine ore requires fine grinding to achieve liberation of minerals. With 25mm slugs as the grinding media in the ball mill, there was a limitation of a P80 of 25 microns on the CuPb regrind circuit. Results from pilot plant testing showed that the separation efficiency could be increased through fine grinding with a P80 of 15 microns.Options considered were the capital expenditure for new fine grinding equipment such as a vertimill or the use of the present ball mill equipment with smaller media. The Wheelabrator Allevard Enterprise (WAE) millpebs product was chosen because it was a smaller media with a distribution of steel pellets between 5 to 12 mm.With millpebs the grinding product was reduced in size from a P80 of 25 microns to a P80 of less than 19 microns. The power draw to achieve the finer grind was 13% lower while the media consumption was 57% higher.The millpebs grinding media was also tested on the zinc regrind mill. The purpose of the trial was to understand what the media consumption and power draw would be with the charge lowered to achieve an equivalent grind as obtained with the slugs. The media consumption was approximately the same and the power draw was reduced by 30%.INTRODUCTIONThe Brunswick Mine ore is a complex Pb-Zn-Cu-Ag sulphide ore with the grain size of the minerals varying from submicron blebs to particles up to several mm in size. The ore is ground progressively finer in stages. The first step of grinding occurs in the SAG mill circuit. The product sizing 80% passing 95 microns is fed to the CuPb prefloat stage (Cormier et al 2002). The tails from the prefloat is then further ground to a P80 of 35 microns for the CuPb rougher flotation. The final liberation for the CuPb circuit takes place in the CuPb regrind circuit. The regrinding mill further liberates the cleaner scavenger concentrate, second cleaner tails and third cleaner tails. The reasoning for the progressive grinding is to achieve fine grinding without having galena over ground due to its high specific gravity that preferentially sends it to the cyclone underflow."

Jan 1, 2006

The Geological Resource Map of New Zealand (GERM) is a computerised inventory of aggregate, mineral, coal, petroleum and thermal water occurrences, containing summary information on location, production, geology, and geochemistry. The types of occurrences include quarries, mines, gold dredges, wells, outcrops, seeps, springs, and fields. The file contains entries for about 10,300 sites and is used to produce tables of data and maps at any scale, for single or multiple commodities. The published format is the New Zealand 'Geological Survey map series Geological Resource Map of New Zealand 1:250 000'. Seventeen of the 27 map sheets covering New Zealand were published by August 1991, with three more close to publication.

Jan 1, 1991

By E. H. Burroughs

This bulletin is the fifth in the series of petroleum bibliographies publis:\:l.ed by the Bure.au of Mines, Bulletins 149, 165, 180, and 189 being compilations for the years 1915, 1916, 1917, and 1918, respectively. In this bulletin the same general plan has been followed in arranging the references, but a few changes and additions have been made in the classification.

Jan 1, 1923

CAPTAIN JOHN H. BALLAMY John H. Ballamy, Captain on the Regimental Staff of the 103d Engineers, was killed near Fismes, on August 9, 1918. Captain Ballamy was born at Plymouth, Pa., in 1886 and graduated from the High School of that town in 1903. In the following year he began work as a coal miner, and at the same time began the study of mining engineering in the evening and any other spare time. He continued this diligent and energetic practice for many years. For sixteen years he continued in the employment of the Delaware, Lackawanna & Western Railroad Company's coal mining department, first as a practical miner, next as rodman on the survey corps, of which he soon became chief, then draftsman and mining engineer in the company's office. In January, 1916, he was promoted to the position of district engineer in charge of mining engineering work. He became a member of this Institute in September, 1917. CAPTAIN JOHN H BALLAMY. Captain Ballamy's military experience began at the same time as his engineering practice. He was a charter member of Company A, Engineers, N. G. P., which was organized ten years ago. He saw service on the Mexican border as First Lieutenant of this Company, and remained in that position until November, 1916. In July, 1917, he was again called into service and was sent to Camp Hancock, Ga., with the 103d Regiment of Engineers. Before joining this regiment he attended a school for officers at Fort Sill, Okla., where he received special training in field fortifications. In December, 1917, he was commissioned Topographical Captain on the Regimental Staff, and in April, 1918, preceded his regiment by about six weeks to France, where he again attended an officers' training school. He rejoined his regiment on July 15, near Chateau Thierry and was killed near Fismes on August 9, 1918.

Jan 11, 1918

By P. A. Mingione

"AEROPHINE@ 3418A is a unique sulfide mineral promoter produced by Cyanamid, based on phosphine (PH3) chemistry. It has proven effective as a collector for the sulfide minerals of copper and particularly lead (galena), as well as for secondary gold and silver values. AEROPHINE 3418A has widest application as a Cu and/or Pb collector for complex ores of Cu-Zn and Pb-Zn, which frequently have significant quantities of associated precious metal values. Advantages shown in the use of AEROPHINE 3418A are improved selectivities against Zn- and Fe-sulfides, increased precious metals recoveries, reduced total collector consumptions for Cu and/or Pb flotation, and increased flotation kinetics leading to higher recoveries of these values. Operating plant, pilot plant and laboratory test data from treating different ores are presented, demonstrating the advantages in use and preferred application of AEROPHINE 3418A.INTRODUCTIONCyanamid operates the only phosphine and phosphine derivatives plant in North America, located in Niagara Falls, Ontario. Specialty chemicals manufactured at this facility are used in many diverse applications, including solvent extraction reagents and textile flame retardants. A unique phosphine-based sulfide mineral promoter, AEROPHINE 3418A, is also produced. The origins of AEROPHINE 3418A promoter date back to the 1960's, when it was established that sulfide mineral collectors based on phosphine chemistry demonstrated efficacy. This new collector chemistry was found to provide flotation performance differing significantly from those of more traditional thiol collector chemistries such as xanthates, dithiophosphates, mercaptobenzothiazoles, thionocarbamates and those with xanthogen groups. Some of the advantages ultimately demonstrated by AEROPHINE 3418A promoter compared to these traditional collectors include:"

Jan 1, 1990

By T. Celik, B. Genc, C. Musingwini

"This paper discusses a new methodology for defining and measuring mine planning software utilization in the South African gold mining sector within an evolving data-set framework. An initial data-set showing the mine planning software providers, their corresponding software solutions, as well as the software capabilities and information on the number of licences was collected and compiled in 2012 in an online database for software utilized in the South African mining industry. Details of the database development and implementation were published in the Journal of the Southern African Institute of Mining and Metallurgyin 2013. In 2014 the data-set was updated with additional and new information. Using the 2012 and 2014 timestamps, a methodology for estimating the software utilization was developed. In this methodology, the three variables of commodity, functionality, and time factor were used to define and measure the software utilization in order to ultimately inform decision-making strategies for optimal software utilization. Using six different functionalities, namely Geological Data Management, Geological Modelling and Resource Estimation, Design and Layout, Scheduling, Financial Valuation, and Optimization, utilization in the gold sector was measured. This paper presents the methodology employed for measuring the mine planning software utilization. The methodology is useful for stakeholders reviewing existing software combinations or intending to purchase new software in the near future and who want to estimate the comparative attractiveness of a certain software package. These stakeholders include mining companies, consulting companies, educational institutions, and software providers. The work presented in this paper is part of a PhD research study in the School of Mining Engineering at the University of the Witwatersrand."

Jan 1, 2015

Recent improvements are described in several techniques for ground control in underground mining. Promising methods for analysis and mitigation of rockbursts are discussed. Methods of assessing damage to underground excavations from repetitive seismic loading are reviewed. Analysis of mining-induced surface subsidence is discussed.

Jan 1, 1989

By Carlos F. Perucca

"Potassium is one of the three basic plant nutrients along with nitrogen and phosphorus. There is no substitute for potassium compounds in agriculture; they are essential to maintain and expand food production.Potash is extracted from buried ancient evaporites by underground or solution mining. This accounts for most of the potassium produced. Another important source is brine from landlocked water bodies, such as the Dead Sea, Salar de Atacama or Great Salt Lake.About 95% of potash produced worldwide is used in agriculture. The rest is found in several other industrial uses, including glass manufacturing, soaps, plastics and pharmaceuticals.Currently, three producers: IMC, PCS and Agrium operate 8 conventional and two solution mines in Saskatchewan, five of which run froth flotation circuits, two heavy media-flotation, two run forced crystallization and one natural crystallization.Potash in SaskatchewanPotash was discovered in Saskatchewan in the early 1940’s while drilling for oil. The deposits lie diagonally across the southern plains of Saskatchewan sloping southerly from a 1,000m depth at Saskatoon to more than 1,600 m depth at Belle Plaine and up to 3,000 m in depth in North Dakota. The known deposits are massive, accounting for more than 40% of the world’s known reserves."

Jan 1, 2003

By A B. Phillips

This paper details the approach adopted to upgrade the current metallurgical facilities at both the Driefontein and Kloof Gold Mines in the Republic of South Africa. Goldfields Ltd operates eight metallurgical plants within South Africa of which three have recently been upgraded to replace the older technology previously installed, with modern equipment. This upgrade was undertaken with a view to improving extraction efficiencies and to reduce operating costs. The upgrade was undertaken in a phased approach with the first phase focused on the replacement of the filtration/zinc precipitation processes with modern pumpcell carbon-in-pulp technology. Included in this upgrade phase was the installation of an automated hands-free electrowinning cell, which represents the first commercial application of its kind in the industry. The second phase of the upgrade entailed replacement of the multiple comminution stages previously installed with large SAG and SAG/Ball mill combinations. Due to the rapid return on these projects, a fast-track approach was adopted which necessitated the purchase of available good conditioned second-hand mills from both within South Africa as well as in Australia. Goldfields Ltd is a large mining house with gold mining operations in South Africa, Australia and Ghana. A well advanced PGM exploration project is underway in Finland- Arctic Platinum.

Jan 1, 2003

The tenth annual Mine Resale Evaluation was held in conjunction with the RMCMI 2001 convention at the Steamboat Springs Sheraton Resort, Steamboat Springs, Colorado June 23 through 26. The purpose of the mine rescue evaluation program is to provide an opportunity for mine rescue teams to learn new skills and improve their existing ones in a non-competitive environment. Several staged ?disaster? scenarios were held where the teams are called upon to exhibit their life saving abilities. The evaluators meanwhile are offering suggestions, both verbal and written, to help the teams better understand the situations presented them. This non-competitive environment allows the teams to work together and share their knowledge with fellow mine rescue teams providing everyone with a positive learning experience. Mine Rescue Chairman Bill Balaz, Balaz & Associates, was in charge of coordinating the events. Six teams consisting of seven to twelve members each (totaling 60 members) participated in the three-day event. Each ream was required to respond to direr different real-life scenarios plus a written general knowledge test daily. Cindy Burnham has assisted Bali, for a few years. Her responsibilities include grading all of the written tests. This year's tour professional evaluators included Art Seanz (Hazardous Ma¬terials) of Western Environmental Associates ; Guy Norton (Ropes), Guy Horton Rope Rescue; Mary Bailey (Medical), MBA Training and Morley Hense (Confined Space). Carolyn Durga, BHP Coal, also assisted in hazardous materials and medical scenarios. They each provided three different challenging mock situations per day per team. The teams had no prior knowledge of what the scenarios would be as details were provided only as they arrived. Ten volunteer victims added much drama and excitement to the event. Their realistic enactment, complete with false blood makeup and severed limbs, made for some very tense scenarios. The Mine Rescue Teams participating this year were BHP LaPlata, BHP Navjo, BHP San Juan, all from Farmington, New Mexico; Bridger Coal Co., Rock Springs, Wyoming; Sabine Mining, Longview, Texas; Solway Minerals, Green River, Wyoming and Western Energy Co., Colstrip, Montana. Many new friendships were made and much knowledge shared. A swap meet was held Saturday afternoon for the teams to exchange miscellaneous equipment, hats, shirts, etc. The trams were asked to evaluate the program and the evaluators. They responded with many positive suggestions that will help improve the upcoming events in the years to come. Culmination of the Mine Rescue program was a Tuesday morning awards breakfast where the teams were presented with trophies. Each member was also given a gold pin with the words Continuing Challenge - Ropes.' The pin was the first in a series that will be given over the next few years. The participating victims and evaluators were also commended for their outstanding efforts. Special signed "Victim" shirts were given to select volunteers. Sponsors for the Mine Rescue program were Flanders Electric Motors, Magnum Metals, Rocky Mountain Electric Motors, Sedona Consulting and Balaz & Associates. Many hours of volunteer tine and effort from various family members of participants helped make the 2001 event a huge success.

Jan 1, 2001

By Ali Porbaha

Rapid growth in the urban development requires continuous search for innovative technologies to construct complex infrastructure systems. Deep mixing is one promising construction technology that has a wide spectrum of applications for development and expansion of complex urban facilities. Large number of reported case history of the projects in Europe, Japan, and the US demonstrate the versatility of the technology compared to conventional methods of ground modification. A large number of factors influence the quality of the soil cement columns; some of these are rooted in the installation process and the effective use of machinery during construction. This paper attempts to present some issues related to installation of deep mixing that affect quality of the treated columns. Presented here are various installation patterns, installation machinery, installation sequence, effect of penetration/withdrawal injection methods, penetration/withdrawal speed, effect of number of shafts, rotation of the blade, shape and orientation of mixing tools, and rotational speed of the shaft on quality of the treated ground.

Jan 1, 2001

Since the 1989 Loma Prieta Earthquake in the San Francisco Bay Area, the California Department of Transportation (CALTRANS) has accelerated seismic upgrading of their bridges. Many structures can be improved with the simple addition of hinge seat restrainers. Others require modification of column bents and superstructure to column connections. Often, footing retrofits are necessary, which require the addition of tension/compression elements (compression piling and tiedowns anchors) to resist overturning moments substantially larger than those originally used for footing design. These footing retrofits may include doweled reinforced concrete footing extensions or new pile caps which transmit forces to either driven steel or drilled concrete piles. In some cases, installation of these traditional piling elements is expensive, impractical or impossible due to: low overhead clearance, ground obstructions, high water table, noise or vibration sensitivity, or the inability to laterally expand the existing plan dimensions of the footing. In the latter case, one practical option is to attach small diameter drilled and grouted tension/compression piling elements (Pin Piles) to the existing footing. The footing may be strengthened with dowels and added concrete thickness or there may be a reduced shear span due to the installation of larger or jacketed columns. A reduction of elements is available with a Pin Pile alternative, particularly when the selection of traditional standard piles is governed by the reduced tension/uplift capacity available from the traditional elements, since Pin Piles exhibit superior uplift performance.

Jan 1, 1993

By J. Gordon Parr, D. H. Polonis

IN a previous study of hypereutectoid Ti-Ni alloys' a substructure was observed in quenched powder specimens when the constitution was 100 pet retained ß body-centered-cubic phase. The alloy powders were quenched from 1000°C by a blast of helium gas and precautions already described were observed throughout the work, to minimize contamination. Ogden et al.2 have previously observed subboundaries in the ß phase of a Ti-Mn-N alloy; but this structure was attributed to nitrogen-rich a precipitation. The nitrogen content of the Ti-Ni alloys does not exceed 0.02 pet and the quenching rate was sufficiently rapid to suppress precipitation reactions. Since X-ray diffraction results have confirmed the absence of any second phase which might account for this phenomenon, it seems unlikely that this substructure is explicable in terms of nitrogen content. Fig. 1 shows the substructure in adjacent grains of 100 pet ß phase in a quenched 6 atomic pet Ni alloy. Fig. 2 shows adjacent ß grains in a similarly treated alloy; one grain contains marked intracrys-talline boundaries and the other is completely free from any substructure. The suberystals appear to have fairly regular shapes, suggesting a regular orientation relationship among them. Tempering the retained ß structure at temperatures below the eutectoid eliminates the substructure at an early stage of ß decomposition. At the present time it is possible only to guess at an explanation for this subboundary phenomenon, since very little work has been reported on substructures resulting from phase changes. It is believed that the present phenomenon is due to poly-gonization resulting from unrelieved stresses set up

Jan 1, 1957

Following a short review of selected literature, a back analysis of stress measurements of stress regeneration in a closed mini-longwall is shown. The agreement is good, lending confidence to the parameters used in the proposed numerical model. Foundation yielding was modelled in the absence of total stope closure. A ?Prandtl? wedge was formed, coinciding with the yield point of the pillar/foundation system. Some theoretical work is used as a starting point for the formulation of a new design methodology for strike or dip stabilizing pillar/foundation systems in deep level goldmines. The existing guideline for the stability of foundations (APS< 2.5UCS) is critically examined. Finally, the advantages of the new approach, and the work required to substantiate the proposed new design methodology, are outlined.

Jan 1, 1998

By A. Holeyman

The displacement compaction piles described in the paper are installed using a heavy casing or tube and an internal drop hammer. The casing which initially is closed at the bottom by a sand plug displaces the surrounding soil during the driving. Additional sand is rammed down through the casing during the extraction of the casing. The applications and limitations of the method are reviewed in the paper. The importance of checking the sand compaction piles during and after the installation is stressed. Indications of the compaction of the surrounding soil during the driving can be obtained by comparing the initial and the redriving logs of the casing as well as from the volume of sand added. A method to estimate the increase of the mean cone resistance as measured by CPT tests in sandy and silty soils is presented. The governing parameters are the volume of the added sand, the granulometric index and the initial cone resistance.

Jan 1, 2010

By Kyle Selga, Christopher J. Greet

"The Pulp Chemistry Monitor (PCM) has been installed and operated in a number of concentrators in Australasia, and has produced some very interesting results. PCM measures the pH, Eh, dissolved oxygen, temperature and oxygen demand of process streams within a concentrator continuously and in real time.In the example presented in the paper the cleaner feed pulp chemistry is measured, and related back to changes in the mineralogy as well as variations in metallurgical response. For example, a decrease in Eh and dissolved oxygen as well as an increase in the oxygen demand. These changes in the pulp chemistry appear to coincide with increases in the feed grades, probably higher pyrite grades. Further, these variations in pulp chemistry and feed mineralogy have a negative impact on the concentrate grade and recovery.The implication is that if the pulp chemistry is monitored it is possible to predict changes in the mineralogy of the system, and from this the metallurgical response. Further, the changes in pulp chemistry can be used in a control system to counter the changes in mineralogy and maintain the metallurgy.IntroductionIt has long been recognized at a fundamental level that the flotation behaviour of sulphide minerals is dependent on the pH and Eh of the system (for example: Tolun and Kitchener, 1964; Woods, 1976). However, measuring pulp chemical parameters within an operating concentrator has had limited attention. Woodcock and Jones (1970a and b) were among the first to actually collect data from operating plants. Jones and Woodcock (1984) identified some of the chemical complexities of flotation pulps, and noted that most concentrators already operate at high levels of metallurgical performance but there was still considerable scope for improvement. These gains would, in part come from more effective chemical control. In the same volume, Healy (1984) discussed metal ion hydrolysis and precipitation, redox chemistry and how the surface chemistry of sulphide minerals can be influence flotation behaviour. The impact of grinding environment on the pulp chemistry and flotation response of a complex polymetallic sulphide ore is discussed by Forssberg and Subrahmanyam (1993). Their work essentially contrasts the pulp chemical and flotation performance of pulps ground with conventional ferrous grinding media to a fully autogenous system. The data suggested that the reduction or removal of iron hydrolysis contamination from the system could have a positive influence on flotation behaviour, and perhaps the first stage of “controlling” the chemistry of the system should be in the grinding circuit. Grano et al (1995) demonstrated that the collection of pulp, solution and surface chemical data could identify weaknesses within a concentrator, and from these data develop, test and implement solutions that improved the process. Greet et al (2006) showed that the pulp chemical trends observed through primary grinding and rougher flotation circuits of most sulphide flotation concentrators are approximately the same. There are differences in the magnitude of various pulp chemical parameters (pH, Eh, dissolved oxygen, temperature and oxygen demand) as a result of variations in the feed mineralogy and processes employed. Further, it was noted the Eh shifted to more reducing values of the ten days measurements were collected, and this change could be traced to an increase in the iron sulphide content of the feed. Metallurgically, this resulted in an increase in nickel recovery through the recovery of nickeliferous iron sulphides, and a decrease in nickel concentrate grade."

Jan 1, 2016

By Bruno Gemmi

The objective of the ? 200 million ($280 million) project Parma Railways Station-Urban Transformation was the reconnection of the North and South parts of the town by constructing an 80 m (250 ft) wide sunken artery passing under the four double railway tracks of the station without any impact on train traffic. The site of the project, adjacent to the Parma River, presented water seepage problems at any excavation depth. The use of conventional large diameter bored pile machinery was not allowed by the Railway Authority because equipment dimension and construction phases do not comply with train traffic safety regulations. Foundations for the bypass were thus constructed by minipiles nested into jet-grouted soil using machinery operating within the existing head room and at a safe distance from the tracks. Jet-grouting treatment reached depths of 25 to 28 m (80 to 90 ft) from tracks? grade and embedded minipile-heads were terminated at 2 to 3 m (6.6 to 10 ft) below grade. Load tests on minipiles were pushed to failure. Failure occurred at a 240 t (265 t) load without breakage of the bond between the jet grouted soil and the minipiles. A 0.93 MPa (135 psi) shear resistance ??? between minipile steel casing and the jet grouted soil was measured prior to the failure of the steel casings. Overall measured foundation settlements were well within expected values and were considered insignificant.

Jan 1, 2011