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By Clayton Williams, Dale M. Hata, Glenn M. Boyce

The Upper Llagas Creek Flood Protection Project in Northern California encompasses portions of the communities of Morgan Hill and Gilroy, and unincorporated areas of Santa Clara County. The project provides for flood protection improvements along Llagas Creek and two of its tributaries, West Little Llagas Creek and East Little Llagas Creek. Llagas Creek is one of the tributaries of the Pajaro River and drains a watershed of approximately 104 square miles. The river system has a history of flooding the watershed communities, and the project’s goal is to provide 100-year flood protection by creating a bypass infrastructure, including channels, cut-and-cover culverts, and a tunnel. The project has been divided into several phases. This paper describes Phase 2A, which consists of approximately 2,150 linear feet of lined horseshoe-shaped bypass tunnel measuring 14 feet wide by 12 feet high. The bypass tunnel was sequentially excavated using a combination of roadheader and controlled blasting through colluvium and weathered to fresh greenstone. The tunnel was mined near residences, requiring strict noise and vibration controls. Phase 2A also includes the construction of twin bypass concrete culverts, portal shoring, and dewatering systems. It features the use of a Design Review Board and partnering for project delivery. This case study discusses the bypass tunnel design, progress of tunnel construction, plans to complete the work, construction risks, and the software and procedural tools being used to manage the project, including ProjectWise construction management software.

Jun 13, 2023

By Campbell Brown GA

IN 1904-5 diamond drilling operations in the Mount Morgan mine proved the presence of some inillioils of tons of rich, copper-gold ore, averaging about 45% to 50% silica and 22%Fe as sulphide. To smelt this ore in blast furnaces, without previous concentration, large quantities of basic flux.were required. Unlimited quantities of cheap, limestone, were available at Marmor, on the GladstoneRockhampton railway, 50 miles from Mount Morgan, but the supply of iron flux was a more difficult problem. Smelting operations started, with one' furnace in January, 1906, using as flux low-grade sulphide ore fro:m. the mine, containing very little silica. When the second, furnace was blown in this was supplemented by ironstone from, small aeposits in the immediate district. It was recognized that these sources of supply would be insufficient to keep the full plant going after the third furnace had been blown in. Accordingly, the deposits at Eabra and Mount Etna were opened, neither of which proved capable of supplying the quantity required viz, 1000 tons per week. Negotiations were meanwhile being conducted with the Marble Island Iron and Limestone Co. to obtain the right to mine at Iron Island, where a sufficiently large deposit was known to exist. Shipments from this source commenced in January, 1907, and ceased at the end of July of this year, when the metallic flux from...

Jan 1, 1912

By T. R. Achenbach

1. This, the final report to the U. S. Bureau of Mines on the program with the subject title, presents the data obtained from June 29, 1973, to April 20, 1974. 2. Operating in the Illinois #6 coal seam, the effectiveness of foam opposed to water was compared in reducing respirable coal dust. A combination of 39 foam generators and 14 water sprays were used during the foam tests. Sixty one water sprays were operated during the water tests. Data from 24 shifts using foam and 21 shifts using water are presented. 3. Additional work on foam generator design should be undertaken to provide coverage to a wider area with foam. 4. The general attitude of those working on the foam program and with the miner at the face was positive. It is urged that the work be continued. 5. The minor respiratory irritations evidently caused by an aerosol effect of the surfactant should be investigated. 6. The statistical analysis of the tests will be made and reported by the U. S. Bureau of Mines.

Jan 1, 1974

By M. Hancer, J. D. Miller

It is known from soluble salt flotation practice that the K, Mg double salts of kainite (KClMgSO43H2O), and carnallite (KClMgCl26H2O) are difficult to float and must be converted to other salts such as schoenite (K2SO4MgSO46H2O) and sylvite (KCl) in order to recover potash values. The flotation characteristics of these double salts have now been confirmed in some detail by carefully controlled laboratory experiments with both cationic and anionic collectors. The experimental results are discussed in view of recent experimental findings regarding the flotation characteristics of simple salts, in which the flotation response was shown to be determined by the interfacial water structure and whether the salt could be considered to be a water structure maker or a water structure breaker. The same approach can be use to explain the flotation response of the potassium double salts ; schoenite, kainite, and carnallite. In addition, the sign of the surface charge of schoenite (K2SO4MgSO46H2O), was determined as a function of pH from nonequilibrium electrophoretic mobility measurements. Schoenite appears to exhibit three charge reversals (CR) which can be explained based on surface hydrolysis reactions. The flotation behavior of schoenite is further considered based on solution chemistry calculations, electrophoretic mobility measurements, and microflotation results.

Jan 1, 2001

Modem mineral exploration and development takes place within a data-rich context underpinned by a wide range of data acquisition, processing and interpretation technologies. This leads to requirements for consistent and explicit methods by which the relative risks - or success probabilities - of exploration programs can be assessed and communicated. Bayesian risk assessment methods are outlined which provide a starting point for this more rigorous approach to exploration investment.   Effective governance of information technologies becomes a core function of the modem competitive Board. As such it becomes a component of any business audit and any assessment of the quality and success potential of a company. Limited data however suggest that the average Board may be under-represented in this increasingly critical skill area.

Jan 1, 1997

By Holger Witthaus

Beside the traditional geomechanical evaluation methods the geotechnical parameters are recognized as important facts of the planning work for multiple seam mining. Standards for applied monitoring and investigation methods for geotechnical determination of drill cores, laboratory rock-tests and observation of roadheadings are the basics for rock mechanics classification and support design. The geomechanical classification is in this context an essential element. The planning procedure, as it is becoming more and more detailed, beginning with the panel layout up to the technical instructions of roadway development and design of roadheading machinery, nowadays uses a lot of geotechnical information that also are expanding to include quantitative determination of more parameters. The current monitoring system includes the description of separation planes using drill cores and roadheading observation as well as laboratory tests of rock-strength and geophysical borehole examinations. This information is analyzed within the geomechanical standard-classification. The re-engineering process of comparison the predicted support success to the actual monitoring results provides the opportunity for continuous optimization of the planning work und support design. This way of empirical analysis is used for basic planning work in Germany for decades. But using the technical standard of information technology and a centralized database now it is possible to reach quick-win effects in implementing research results on the one hand and actual experiences on the other hand.

Jan 1, 2006

By Robert Martin, Brian W. Stump, David P. Anderson, W Scott Philips

Since 1994, various mines in the US have cooperated with research scientists at the Los Alamos and Lawrence Livermore National Laboratories to address issues related to verification of the Comprehensive Test Ban Treaty (CTBT). The .CTBT requires that no country may conduct any nuclear explosion in the future. While the CTBT is a significant step toward reducing the global nuclear danger, verifying compliance with the treaty requires that the monitoring system be able to detect, locate and identify much larger numbers of smaller amplitude seismic events than had been required previously. Large mining blasts conducted world-wide will be of sufficient amplitude to trigger the monitoring system at the lower threshold. It is therefore imperative that research into the range various blasting practices employed, the relationship of yield to seismic magnitude, and identification of anomalous blasting results be performed. This paper will describe a suite of experiments funded by the Department of Energy and conducted by the Los Alamos and Lawrence Livermore National Laboratories in cooperation with the US mining industry. Observations of cast blasting, underground long wall generated coal bumps, stoping, and explosively induced collapse of room and pillar panels will be presented. Results of these dual use experiments which are of interest to the mining community will be discussed. These include 1) variation of amplitude of seismic energy at various azimuths from cast blasts, 2) identification of the extent of back failure following explosive removal of pillars, and 3) the use of single fired shots for calibration of the monitoring system. The wealth of information and discovery described in this paper is a direct result of mutual cooperation between the US Government and the US Mining Industry.

Jan 1, 1997

A study of literature on the epidiorite dykes which transgress the Broken Hill lode and its wall rocks reveals a considerable diversity of thought regarding the time of emplacement of such dykes. In this paper it is deduced that the epidiorite dykes were formed at a late stage and were probably post-ore. Detailed mapping, sampling, and correlation of data from over 100 exposures substantiates this deduction. Physical disruption of the epidiorite dykes is indicated and some interaction of the epidiorite and ore at the time of intrusion is inferred.Further petrological study may confirm this.

Jan 1, 1968

By F. Stober, D. Wanblad, J. Ndlovu, L. R. Nelson, L. P. S. de Villiers

The single six-in-line furnace of the Polokwane Smelter is the largest installed high-intensity furnace for platinum group metals (PGM) base metals sulphide smelting in the world. The furnace employs state-of-the art technology to deliver a planned throughput of 650 000 t/a dry concentrate at a design 68 MW power input. This furnace, at double the capacity of previously existing PGM furnaces, offers low unit operating and capital cost through the resulting economies of scale. Key features of the design include:

Jan 1, 2005

This Institute, by nature of its charter, draws on various persons in the mining and metallurgical world of Australasia for its President from year to year, and consequently when the presidential address is given by one of these people the topic. which they generally select is a topic to which they are accustomed and on which they are able to speak with authority.As most of you know, my prime object in life has been concerned with steelmaking, so tonight you can steel yourself to the thought that you are going to be spoken to about steelmaking.Even if that were not the case, and were I not particularly interested in steelmaking, I think it would be appropriate to look at steelmaking in a broad sense on a basis of pure metallurgical interest, because the steel industry is going through as big a revolution today as it went through something over one hundred years ago when Bessemer made a theory become a fact.Bessemer, and as the Americans prefer to think Kelly, separately conceived the idea of blowing cold air through molten pig iron, and, contrary to the then general belief, this did not result in cooling of the metal but succeeded rather in heating it, and in burning out of the rather crude pig iron the impurities which prevented it from becoming a ductile metal.For many years before this, steel had been made in a very small painstaking way by what was known as the crucible process. Benjamin Huntsman is credited with having developed the crucible steel making process to a stage where it could make a reliable and trustworthy product, but he...

Jan 1, 1961

By J. K. Afidenyo, J. Osei-Owusu

"The Obuasi Mine of AngloGold Ashanti Limited has been operating the world’s largest Biooxidation Plant at its Sulfide Treatment Plant (STP) in Ghana, using the Gencor Biox® technology since February 1994. The Biox® technology was preferred to other alternative methods of treating refractory sulfide ores such as roasting, pressure oxidation and nitric acid leaching due to among other reasons, its lower capital and operating costs, reduced technical risk, relatively benign environmental impact and its ease of operation and maintenance in a remote location.STP has since commissioning succeeded in operating this technology successfully but not without some operational problems. The Plant has seen a number of upgrades and modifications in its circuits which were motivated by cost, operational and throughput constraints.The objective of this paper is therefore to highlight the mine’s experience in the treatment of its complex carbonaceous refractory sulfide gold ores with emphasis on plant operations and improvements such as the Biox® reactors expansion, flotation concentrate upgrade project and neutralization circuit modifications. The Biox® Plant operating cost is also discussed.INTRODUCTIONThe Obuasi mine forms part of the AngloGold Ashanti Group of Gold Mines. It is located in the Adansi West District of the Republic of Ghana. The mine is primarily an underground operation, although some surface mining still takes place. Ore is processed by two main treatment plants: the Sulfide Treatment Plant (for underground ore) and the Tailings plant (for tailings reclamation operations). A third plant, the Oxide Plant, is used to batch-treat remnant opencast ore and stockpiles, of which there are adequate tonnages to keep the plant operational until 2008.Though reference is made in this paper to the Tailings and Oxide Treatment Plants, the main focus will be on the Sulfide Treatment Plant."

Jan 1, 2008

By A. M. Neale

Kriel Colliery has experienced some sub-standard blast results on the overburden. Blast results are considered poor when the fragmentation is too big, back break into the new highwall, capping is experienced and/or excess overburden material is thrown into the void. Poor blasting leads to lower productivity, equipment breakdowns, and poor drilling and blasting results on the adjacent blast, contamination of coal or loss of coal. A simulation was developed in Microsoft Excel to model blasting results while changing various parameters. From the simulation results, it could be seen that a change of blast design could be beneficial. As an example, smaller drilling patterns were simulated (10 m x10 m to 8 m x8 m, and 8 m x8 m to 7 m x7 m in Pit 5 and Pit 6 respectively) in combination with changes in explosives (P700 emulsion vs. ANFO) and drill bit diameter (311 mm vs. 251 mm). The results show that each of the options has a specific scenario that will be most beneficial to the mine. These results are quite specific and subject to variable inputs. The purpose of the example is to demonstrate how the simulation can be used as a tool to asses blast design variations.

Jan 1, 2010

By Robert R. Perron

The U.S. Bureau of Mines is engaged in many diverse programs fur improving mine safety. One area of interest to the Bureau is new and improved means for minimizing the hazards of accidental gas ignition or electrical shock should the frame of an off-track machine assume potential above ground. Various means presently used to prevent such occurences are the use of ground fault detectors for phase to ground faults in ac machines, and grounding conductors and diodes in dc machines. In a three phase ac power center, a phase to ground fault may be detected by monitoring the current in the grounding resistor which is required between the power center neutral on the load side of the power center transformer and ground. Another method for detecting a ground fault is to pass the three load conductors through a toroidal core transformer. The phase currents vectorially add up to zero if none of the phases are faulted, and hence the voltage of the transformer secondary is either zero or not zero if one of the phases is unbalanced or faulted.

Jan 1, 1976

By T J. Napier-Munn

This paper proceeds from the premise that process improvement is a key part of the mineral engineer’s role, and one in which he/she can make a significant contribution to shareholder value. It presents four tools to help with process improvement projects. Two are designed for process monitoring, to determine as soon as possible whether there has been a true change in performance: the cumulative sum (cusum) control chart plot with V-mask, and the control chart using a process model. The other two are used for process optimisation: simplex self-directing evolutionary operation (SSDEVOP), and a response surface model developed using a central composite rotatable experimental design (CCRD). These methods are robust, have a rigorous theoretical basis and are easy to implement. They also promote project continuity which increases the chances of success, particularly in fly-in/fly-out (FIFO) operations. Variants are used in other industries, but they are rarely if ever applied in mineral processing to-day for reasons which are unclear. The paper gives examples of the application of each method in concentrators which demonstrate that they have the potential to be useful additions to the mineral engineer’s professional toolbox.CITATION:Napier-Munn, T J, 2014. Cunning solutions to process improvement, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 5–10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By George Straghan, Ralph Thomas

OIL production in Kentucky in 1941 was 5,191,024 bbl., one barrel less than in the preceding year. The total completions for the state numbered 714, of which 256 were gas Manuscript received at the office of the Institute Feb. 26. 1942. * Geologist, .Kentucky Weal Virginia Gas Co., Ashland, Ky. † Geoloneist. Inland Gas Co.. Ashland. Kv. producers, 220 oil wells, and 227 dry holes. The total number was 95 more than in 1940. No new important oil or gas pools were discovered. The number of dry tests was large, although many of the dry holes could be considered wildcat tests. In western Kentucky, 365 wells were drilled, of which 145 were oil producers,

Jan 1, 1942

By Ralph Thomas, George Straghan

OIL production in Kentucky in 1941 was 5,191,024 bbl., one barrel less than in the preceding year. The total completions for the state numbered 714, of which 256 were gas Manuscript received at the office of the Institute Feb. 26. 1942. * Geologist, .Kentucky Weal Virginia Gas Co., Ashland, Ky. † Geoloneist. Inland Gas Co.. Ashland. Kv. producers, 220 oil wells, and 227 dry holes. The total number was 95 more than in 1940. No new important oil or gas pools were discovered. The number of dry tests was large, although many of the dry holes could be considered wildcat tests. In western Kentucky, 365 wells were drilled, of which 145 were oil producers,

Jan 1, 1942

By Charles Bohdanowicz

As in preceding years, the most intensive drilling activity during 1934 took place in the old fields of the western part of the Polish Carpathian petroleum province (district of Jaslo). The number of wells completed to the end of 1934, expressed in percentages, is as follows: Jaslo district, 57 per cent; oil fields outside Boryslaw-Tustanowice-Mraznica, 27; Stanislawow district 8 and Boryslaw fields only 7 per cent. The number of meters drilled (Table 2), expressed in percentages, for the same fields are as follows: Jaslo district, 51 per cent; oil fields outside Boryslaw-Tustanowice-Mraznica, 26; Stanislawow district, 12, and Boryslaw oil fields, 11 per cent. This comparison shows that most of the new

Jan 1, 1935

CLASSIFICATIONS: 1, Nonferrous metals. 2, Iron and Steel. 3, Petroleum and Gas. 4, Coal. 5, Industrial minerals. A, Geology, exploration. B, Mining and production engineering. C, Preparation and milling. D, Physical metallurgy. E, Administration and economics. F, Chemical metallurgy. G, General. ARIZONA HASTINGS. EARL F., P. 0. Box 10 Chloride 1-A,B,C, Denver Univ., Texas Call. Mines. Asst. chief metallurgist, Old Dominion Copper Co., '26-'29; mine examination and mill construction in Colo.. Ariz.. and New Mexico; mill supt., Arizona Molybdenum Corp.. 34; at present gen. mgr., Pioneer Gold Mng. Co. Specialty: mine examinations and flow sheets of gold and rare metal plants. Examinations limited in Mohave County, A.riz., for present.

Jan 1, 1936

By P. Kluge

Mining engineers frequently encounter complex design problems for which the critical components of the design are difficult to quantify or compare. Teams of people typically work on these designs and human perceptions and judgments play a strong role. To assist with this process, the analytical hierarchical process (AHP) as a decisionmaking tool is described in this paper. Although the technique is used in many other disciplines, it is currently not widely used in mining engineering in South Africa. To use the AHP process, the problem should be treated as a hierarchy that defines the goal, the alternatives to reach it, and the criteria for evaluation of these alternatives. Pair wise comparisons are conducted on the criteria of the hierarchy to establish priorities. The value of the technique is that it is simple to test for consistency amongst the pair wise comparisons to ensure that the answer obtained is better than that provided by a random selection. To illustrate the technique, the use of a backfill support system in a platinum mining project was investigated. Ten design parameters, which will be impacted by the use of backfill, were identified and weighted according to their relative importance. The result of the AHP evaluation was that the use of a backfill support system should be preferred to a conventional support system at the mine.

Jan 1, 2011

By J. -W. Kim, Y. -B. Kang, H. -G. Lee

The effect of SiO2addition on the decomposition of Li2CO3was investigated at temperatures up to 1000ºC. It was found that addition of SiO2greatly enhanced the decomposition of Li2CO3. The main decomposition reaction started at around 600ºC, and completed just above the melting point of Li2CO3. The major decomposition product was Li2O?SiO2irrespective of the Li2CO3to SiO2mixing ratio while both reactants were available. It was ascertained that a liquid layer betweenLi2CO3and SiO2particles formed and facilitated the decomposition reaction. The governing reaction of the decomposition was the one between the dissolved Li2CO3and SiO2in the liquid layer to form Li2O?SiO2. The decomposition rate was independent of the Li2CO3/SiO2mixingratio until either one had been completely exhausted. When excess Li2CO3existed, it further reacted with the initial product of Li2O?SiO2to form 2Li2O?SiO2. When SiO2was found in excess, on the other hand, no further reaction took place. This is attributed to the fact that uponLi2CO3exhaustion there is no liquid phase available to facilitate further reaction. The apparent activation energy of the decomposition of Li2CO3in existence with SiO2is 198 kJ mol-1.

Jan 1, 2004