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By William H. Waggaman

The United States not only is the largest producer of phosphate rock but also manufactures and consumes greater quantities of phosphate products than any other country. New and expanding uses will increase even further the demand for this basic raw material. Only a small proportion of the total quantity of phosphate rock mined and marketed is consumed directly in a raw or unprocessed state; the vast bulk is chemically treated and converted into [ertilizer] and a wide variety of finished products that play a vital role in [r] national economy. Three fundamental methods are employed in decomposing phosphate rock. 1. Reduction by carbon at high temperatures. 2. Treatment with one or more acids. 3. Calcination or fusion with silica, sodium salts, magnesium minerals, or small quantities of phosphoric acid.

Jan 1, 1960

By J. A. Stampe

In connection with its investigations of strategic minerals in the United States, the Bureau of Mines ran magnetic surveys totaling more than 533,000 linear feet at 30 deposits of magnetite in northern New Jersey. These deposits occur in a belt of granitic gneiss and in limited areas of limestone. The ore consists of magnetite accompanied by score of the following minerals: Hornblende, augite, apatite, feldspar, biotite, calcite, garnet and pyrolusite. Results of these investigations are being presented in two reports of which this is the second. The first paper, Certain. Magnetite Deposits in New Jersey, by A. L. Neumann and McHenry Mosier, was issued in April 1948 as Report of Investigations 4225.

Jan 1, 1949

Traditional fine grinding mills in mineral processing relied on the use of steel medium for particle size reduction. The successful development of the Isa Mill(a horizontal stirred mill with 3000 litres of net chamber volume and 1120 kW rated motor power)adopted a novel product separator design that has led to a major revision of medium use in fine grinding. The Isa Mill separator has also successfully operated with a wide variety of medium types such as silica sands, river gravel, smelter slag, run-of-mine ore fractions and steel shots, with size ranges from 0.5 to 10 mm. A great flexibility of the Isa Mill operations has been achieved for processing a feed as coarse as 120 um to a product as fine as 5 µm. This paper discusses the performance of two inert grinding media used in the Isa Mills in Mount Isa Mines of Australia for processing galena and sphalerite bearing ores to below 10 microns. They are the copper reverberatory furnace slag (CRFS)and the heavy medium plant rejects (HMPR). A methodology was also demonstrated for comparing the medium performance and for scaling up the Isa Mills from a 1.5-litre laboratory batch mill to a full scale 3000-litre mill.

Jan 1, 2000

By Wilton Johnson

Native asphalt was produced in 1981 by five companies in three States, Alabama, Texas, and Utah. Texas was the leading State in production of native asphalt. Total production increased in 1981 to 1.26 million tons, while value increased 10.5% to $27.7 million. Bituminous limestone, used primarily for street and road repair, was produced by Whites Uvalde Mines and Uvalde Rock Asphalt Co., both in Uvalde County, Tex., and Southern Stone Co., Colbert County, Ala. Gilsonite was produced by American Gilsonite Co., Uinta County, Utah, and Ziegler Chemical and Mineral Corp., Weber County, Utah. This material was used for purposes other than road repair.

Jan 1, 1982

By R. Hart

In this paper, problems that have been experienced with the rockpass system at Kloof Mine No. 3 Shaft are described. Actions that have been taken to overcome the problems are also described. These include the use of slugshots to remove hang-ups, the abandonment and waste filling of passes, and design criteria adopted for an alternative pass system.

Jan 1, 2006

By R. W. Fedors, S. T. Green, F. T. Dodge, D. B. Walter

Spatial and temporal temperature variations in a high-level radioactive waste repository drift can give rise to moisture transport within the drift. Knowledge of this moisture transport may be important to assessing the potential for corrosion of all metallic components in the drift. The model presented here shows one approach to simulating evaporation, transport, and condensation of water in large underground openings using a framework based on computational fluid dynamics. Simulation results that explicitly model water and latent heat transport are presented.

Jan 1, 2004

By Martin Herrenknecht

The world?s growing population and rapidly proceeding urbanization are boosting an enormous demand for new and high-capacity infrastructures to secure the mobility of goods and people. Densely populated areas face the challenge to provide efficient traffic infrastructure, such as a modern public transportation system. At the same time, the maintenance and modernization of supply and disposal structures for water, sewage, energy and communication are also essential. Additionally, supra-regional transportation routes such as long distance water diversion schemes are the challenges for the future. All these projects are as demanding as they are characterized by a tight time schedule.

Jan 1, 2010

By Michael Hood

An overview is given of some of the major mining research activities in Australia. Automation of mining equipment is not an objective in its own right. The objective is to improve the safety and the economic performance of mining operations. Automation can be a useful method for achieving this objective. There is a strong focus on mining equipment automation and related issues and specific examples of ongoing and recently completed automation projects are described.

May 1, 2002

By E. R. Bauer

In response to the mandates in the MINER Act of 2006, NIOSH conducted refuge alternatives research that included characterizing the utility, practicality and survivability of refuge chambers and outby safe havens. NIOSH also prepared and delivered a report to Congress in late December 2007 that summarized the findings of the research, included recommendations concerning the design and performance specifications for refuge alternatives, and focused on specific information that could inform the regulatory process on refuge alternatives. This document highlights NIOSH's research and recommendations concerning refuge alternatives, survivability evaluations of refuge chambers, and presents a brief review of the current deployment of refuge chambers in underground coal mines in the U.S. The research has lead to the conclusion that refuge alternatives have the potential for saving the lives of mine workers if they are part of a comprehensive escape and rescue plan, and if appropriate training is provided. DISCLAIMER: ?The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.?

Jan 1, 2009

By Patrick E. Durnal

The Richmond-San Rafael Bridge was built in the early 50s' and was first opened to traffic on August 31, 1956. Among California's longest steel bridges, it spans more than 21,000 feet across the northern portion of San Francisco Bay. It is one of six toll bridges currently undergoing seismic retrofit in the Bay area. Current retrofit criteria require the structure not to collapse in a Magnitude 8.3 earthquake lasting 45 seconds on the San Andreas Fault. The earthquake epicenter is 10 miles to the west of the Bridge, near the mouth of San Francisco Bay. Another major fault is the Hayward Fault, with a potential of a 7.5 magnitude earthquake. It is only 4 miles east of the eastern end of the bridge. The retrofit criterion is that the structure survives these earthquakes without collapse or loss of life, and that they are capable of repair within a period of one year. Therefore an energy absorbing, ductility and nominal resistance based approach to the retrofit design have been adopted for the retrofit of this bridge. Foundation Retrofit The foundation retrofits were designed to satisfy of drift criteria of 6 inches at the base of the footings, and to keep the existing H-piles from experiencing unacceptable levels of permanent soil displacement and /or structural rupture. Full-scale structural lateral load testing of BP14x89 piling, to rupture, has helped to determine the drift criteria. However recent non-linear analytical results, have led to a redesign, which may allow for 12 inches of drift. The as-built analysis of the Micropile piers determined that those piers would not exceed the 6-inch drift criteria so lateral resisting shear piles were not needed at those piers.

Jan 1, 1998

Once every three years the eyes of the construction and mining industry?s turn to Munich, Germany for the bauma trade fair and exhibition. From April 19-25, Messe München International (MMI) will host the 29th edition of this massive show that, despite the recent recession and global financial struggles, has grown yet again. The show, which is completely booked, will take place on a record 555,000 m2 (5.9 million sq ft) of indoor and outdoor exhibition space at the New Munich Trade Fair Centre. More than 3,000 exhibitors are expected to make use of this event. To prepare for the show that highlights some of the largest and most impressive construction and mining equipment in the world, Messe München began working months in advance on getting the infrastructure on the open-air site ready, in time for the arrival of the gigantic machinery exhibits, which started to arrive in March. Part of the preparations include a new entrance at the northwest corner of the exhibition center that was built to regulate visitor flow better. This should help with bauma considering that in 2007 more than 500,000 visitors passed through the gates. ?Although in 2010 the construction machinery sector in many markets worldwide will be recovering only slowly from the recession, we are pleased to report that we are seeing strong demand for exhibition space. This shows that exhibitors regard participation in the world?s leading trade fair bauma as a must, although many are at present having to make cuts in their advertising and trade-fair budgets. We have been particularly surprised by the strong demand for space from exhibitors from markets like China, India and Turkey. The fair is fully booked and many more companies are on the waiting list,? said Eugen Egetenmeir, managing director of Messe München. More than 50 percent of the exhibitors at bauma 2010 come from countries outside of Germany. While the show?s primary focus is on the construction section, it is not as if the mining sector will be difficult to find. With some of the largest equipment in world on display in section C2 (Fig. 1), the mining industry is sure to be well-represented.

Jan 4, 2010

By M. Pernot

A 12 m-deep excavation has to be perfomed in the Shanghai soft clay to install an underground electric substation. This article was originally intended to study the behaviour of the wall, the excavation bottom and the surrounding ground during the excavation. Since the works are behind schedule, and the data referring to the excavations are not, therefore, available, the article is limited to a presentation of the analysis methods that we envisaged for the study of the behaviour of the excavation.

Jan 1, 2010

By R Adofo

Underpinning the mining process is a continuum of prediction, specifically of tonnes, grade and recovery from exploration to grade control, through short-term mine design, to mining and processing. The interdependence of one activity on the other is so strong that it can be difficult to partition the activities and determine where there are issues, if any. Reconciliation is the process that compares the predictions of the various estimates to the actual product produced at the end of the production chain. Quite often, an attempt to understand the variances from one measuring point to the other creates a ‘wicked problem’.This study outlines the benefits of incorporating the principles of ‘systems thinking’ into the mining reconciliation process, by constructing a framework within which reconciliation is effectively managed. The philosophical base for any variances between successive links in the reconciliation chain cannot be attributed purely to the statistical variance between the predicted and the actual grades achieved, but should include the interrelationships between the technical and managerial professionals involved. Systems thinking, as an interdisciplinary approach, draws its ideas and concepts from a variety of disciplines, and in so doing can exploit their different strengths.The study described in this paper offers methodologies to analyse the task, in advance of developing a technical solution. Two systems thinking methodologies, Grounded Theory (GT) and Soft Systems Methodology (SSM) were employed. These methodologies, are geared towards dealing with relationships and interactions between individual parts and the whole. The GT coding in the study specified that the key activity that would drive the reconciliation process is through an effective reconciliation meeting, and the competencies of a ‘reconciliation team member’ This team member should be a good communicator and enjoy challenges, be open-minded and transparent, and have a broad perspective of the mining process and relationships across the different activities.CITATION:Adofo, R, 2017. A systemic approach to managing the Mine to Mill reconciliation process, in Proceedings Tenth International Mining Geology Conference 2017, pp 95–102 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Robert B. Bittner

The Sutong Bridge across the lower Yangtze River in China will have, when completed, the longest span (1,088 m) and the highest towers (306 m) of any cable stayed span in the world. The foundations for this record setting span will also be record setting. They are located in water depths exceeding 30 m with maximum flows exceeding 3 m/sec. The soil at the site of the main pylons consists of layers of silty sands and silty clays extending to bed rock at 270 m below river elevation. This paper describes the innovative methods used by the team of foundation designers and constructors to support this record setting bridge at this very challenging site. This paper covers three specific topics related to the foundations of the Sutong Bridge: ? Design and construction of the 131 drilled shafts (2.8/2.5 m diameter and 114/117 m long) under each of the two main pylons, including the post-grouting of all drilled shaft tips. ? Design and construction of the scour protection for the two main pylons. ? Construction methods used to construct the waterline pile caps (113.8 m by 48.1 m by 13.3 m deep) under each pylon.

Jan 1, 2007

To form a true picture of the early history of Queensland, we must think of white settlement advancing like an incoming tide, wave by wave; each wave lapping ahead a little further than the last. The credit for opening up the country belongs to a large number of pioneers, each of whom pushed out just a little further than his predecessors.Contrary to what one might expect, Rockhampton district was settled by overlanders from the south and not from the ocean side. When the Archers, the pioneers of the Rockhampton district, reached Gracemere in 1853, settlement had already made its way down the valley of the Dawson River; for it was from Leith Hay's station at Rannes (a few miles below Mount Morgan) that the Archers advanced northward into the unknown, to find the river that the explorer, Ludwig Leichhardt, had told them must enter the sea somewhere near the Tropic of Capricorn.The Archers travelled northward from Rannes up the valley of the Dee, coming out on the edge of the Razorback Range not very far from the point at which the Dawson Valley Highway drops over into Poison Creek. (Their diary records the bearings from a lookout point to various peaks around Rockhampton, and to-day, by plotting back from these peaks, we can determine the exact spot at which they descended on to the Fitzroy Flats.) We can be certain, then, that they must have been the first white men to set eyes on Mount Morgan; though to them it would have seemed to be nothing more than an insignificant hill...

Jan 1, 1939

By L Semenyna, W Douglas

Gold is often present in solid solution with pyrite in the Carlin Trend. The presence of organic carbon along with gold hosted in sulfide, referred to as double refractory ore, requires that ore with high carbon-in-leach (CIL) preg-robbing potential and poor leach recovery is routed to a roaster. During roasting, the pyrite is oxidised to (ideally) form hematite (Fe2O3), and the gold that was present as solid solution in the pyrite forms colloids within the hematite. The ideal texture of the produced hematite is porous to allow for the penetration of cyanide for gold dissolution. Temperature and other conditions of roasting, as well as ore characteristics (pyrite mineral associations, arsenic) can affect the texture and the type of iron oxide formed. Many of these alternate iron oxide minerals result in incomplete leaching. Comprehensive gold deportment studies have proven that the majority of the gold losses in Barrick GoldstrikeÆs roaster leach tailings occur within the iron oxides created through the roasting process.The iron oxide phase that hosts the majority of the gold in tailings is in the form of by-product maghemite (?Fe2O3), which is highly magnetic. Barrick Goldstrike has designed a magnetic recovery circuit to capture these iron oxides, and with subsequent reprocessing, recover the lost gold. Pilot plant results and analysis using scanning electron microscope mineral liberation analyser (SEM MLA) shows that up to 30 per cent of the gold in tailings can be recovered with a three per cent overall mass pull to magnetic concentrate. This magnetic concentrate can be economically reprocessed, resulting in a three per cent improvement in roaster recovery.CITATION:Douglas, W and Semenyna, L, 2013. Magnetic recovery of gold-bearing iron oxides at Barrick GoldstrikeÆs roaster, in Proceedings World Gold 2013 , pp 79-86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By D. Pappas

Over the past decade the number of contractors working in underground coal mines has nearly doubled; however, the effect this has had on the industry?s injury rates has been the subject of much speculation. The confusion exists because the U.S. Mine Safety and Health Administration (MSHA) database does not assign contractor hours to the individual mining operations where they worked. To better understand the safety record of the contractor segment of the industry, the National Institute for Occupational Safety and Health (NIOSH) undertook a comprehensive analysis of the data contained in the MSHA database. The first part of the study compared overall contractor and operator trends from 1983 to 2009 related to employment, hours worked, injury rate, and days lost. One unexpected finding was that the larger contractors tended to have higher injury rates than the smaller ones. The second part of the study directly addressed the role of contractors on the safety record of 10 large underground coal mines. A detailed analysis provided both injuries and estimated contractor hours worked at these mines for the period 1992?2007. Comparison between the estimated contractor injury rates and the reported operator injury rates at these mines indicated that the contractor injury rates were significantly higher at most of the operations studied. However, the industry-wide data indicates that contractor and operator injury rates have converged since 2005 and are now equivalent.

Jan 1, 2011

By L Bartsch, M Kelahan, E Wingate, J-S David

The use of column flotation cells for recovery of phosphate is becoming more common practice in certain parts of the world (Brazil, Russia) where igneous phosphate ores are processed. Igneous phosphates are generally finer grained (< 200µm) than some of the traditional sedimentary phosphates (<400µm). Australian phosphate from the Georgina basin is sedimentary, but has a much finer grain size (typically < 106µm) than similar deposits in North Africa and the USA.In 2013, Arianne Phosphate completed a bankable feasibility study for the development of their igneous phosphate deposit at the Lac a Paul site in Quebec. Initially, lab test work and bench scale piloting indicated that using traditional mechanical flotation would be able to produce adequate concentrate grade and an economic level of recovery, but would necessitate the installation of a complex and operationally challenging flotation circuit. Later pilot plant testing using column cells resulted in a significant reduction in process complexity and facilitated the processing of the -20µm ore fraction which resulted in a 10% increase in P2O5 recovery and a 5% increase in concentrate grade %P2O5.Flotation column testing achieved a concentrate grade of 38.6% P2O5 at a P2O5 recovery of 90%. Using a mechanical flotation cell circuit, the concentrate grade was 36.4% P2O5 with a P2O5 recovery of only 78.8%. A noticeable feature of the testing was the simplicity of the column flotation circuit configuration (Rougher + 2 stages of cleaning + Cleaner Scavenger) compared to the mechanical flotation cell circuit (Rougher + Scavenger + 3 stages of cleaning).The financial benefit for this case study was estimated using a sales price of US$ 195/t FOB for a 38.6% P2O5 product, and an assumed cost of production of US$ 95/t, the netback price is calculated at US$100/t. For a daily milling rate of 55,000t/d, the improved flotation performance provides additional concentrate production of 1,203t/d. Using the netback price calculated above, this calculates to additional gross profit of US$ 120,260/d.Annualised, this equals US$ 40.7 million in additional revenue for a similar or reduced CAPEX.The use of column flotation on fine grained phosphate ore types often requires fine grinding and desliming to liberate the phosphate value, such as the Australian sedimentary phosphate ores. This may enable the development of deposits previously regarded as uneconomic.This paper discusses the potential benefits available to operators, and developers of new projects, for the use of column flotation cells in their metallurgical circuits as assessed by an engineering company.CITATION:Wingate, E, Kelahan, M, David, J-S and Bartsch, L, 2015. Does it make cent$ to use flotation columns for phosphate beneficiation?, in Proceedings MetPlant 2015, pp 353–365 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Thomas Gales

Longwall mining of thin shallow coal seams utilizing open pits is technically feasible. The thinnest coal seam which can be mined using available technology is 34 inches. The capital expenditure for a 1,000,000 ton per year operation is $15,494,000, and the projected rate of return is 5 percent. Similar statistics for a conventional area surface mine are S18,937,000 capital and 14 percent rate of return. The longwall surface mining method disturbs 63 acres of land per 1,000,000 tons, and the conventional area surface mine disturbs 198 acres A significant bibliography of the technology involved is included.

Jan 1, 1976

By R. L. Grayson

Using powerful database management software, nested-field analysis and microanalysis of narratives have been made of West Virginia accident data, resulting in a new approach for targeting and prioritizing safety interventions by county, mine size, specific mine, job title, type injury, etc. and combinations of these parameters. The analyses have been useful in focusing training and discussion sessions on specific work problems, trends, conditions, and situations for targeted groups of miners. Application of the technique will be presented in this paper, along with comparisons of various mine performance measures.

Jan 1, 1997