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By Patricia Negrini Siqueira

Abstract. Polymers are susceptible to changes in their chemical structures that affect their mechanical properties under weather condition. Exposure of plastics to UV radiation causes a loss in their mechanical properties and/or change in appearance, including reduced ductility, color changes, yellowing and cracking. Today, there are several additive systems (light stabilizers) developed to work according to resin, final application, type of cultivation, and other characteristics. This study evaluates the different additive systems (Hindered Amine Light Stabilizer - HALS, nano calcium carbonate - NPCC, nZnO and nTiO2), applied 0.75% (in weight) in linear low density polyethylene (LLDPE). The samples were mixed by high rotation homogenizer and extrusion. Later, the samples were molded by injection and aged in QUV-B simulating 6 months of exposure to weather. Tests of FT-IR and tensile strength comparing to the non-aged samples were carried out in order to evaluate the performance of several additive systems.

Jan 1, 2015

By Enrique Francisco Somolinos Garcia-Morales

In this paper we will discuss the benefits of a very innovative way of introducing MgO in the blast furnace operation through the sinter, using mini lumps of dunite. By changing the traditional way of using an MgO bearing material in fines form (particle smaller than 5 mm), most of the MgO inserted material behaves as inert during the sintering process, with the effect of having the following parameters (among others) improved: productivity at the sintering bed, permeability inside the blast furnace, energy consumption, stability of the operation.

Aug 1, 2018

By William J. Robinson

What is the cumulative rate of recovery of copper from a sulfide leach dump? The technical answers to this frequently asked question may vary from "I don't know" to "quite good" from people of the same company. Management also poses this question because it plays a vital role in planning future production. The answer is difficult because of the many variables between different operations such as physical construction of the dump, topography of the original site, characteristics of dump material, mineralization, and water application. Each of these factors and others have a bearing on the rate of recovery. Anaconda's method of water distribution at Butte is unique in that each dump is drilled to allow physical injection of water into the dump. The injection holes are drilled vertically on 25-ft centers from the surface of the dump [(Figs. 1 and 2)]. Normally, the holes are drilled 40 ft deep and cased with 4-in. PVC perforated pipe. The pipe is perforated at 1-ft intervals with four 1 -in.-diam holes at 90° spacing on the pipe circumference. Formerly, shallow holes (20-40 ft) were alternated with deep holes (80-180 ft) in an effort to cover the entire dump and hasten oxidation. The shallow hole depth varied according to the compaction thickness. The deep hole depth varied according to the height of the dump and the original ground profile. It is preferable to have the deep holes end 20-30 ft above the original ground level. This generally allows penetration of the coarse material at the bottom of the dump. Deep holes had to be discontinued in order to cover more

Jan 1, 1974

JAN. 17-In what appears to be a general spirit of post-Christmas emotional malaise, most adult Americans have bidden farewell to the Forties and turned with no perceptible enthusiasm toward the Fifties. The dying decade had started amid a phoney war which verged on the romantic, stirred the pulse with excitement and seemed far away. A phoney peace dominates the new decade. The romance is no longer there. Nor is the excitement. Nor is the distance. While most of the world preferred to be chronologically correct and hold off for another year before celebrating the demise of the first half of the twentieth century, the United States with true competitive enterprise and a great whirl of words scurried into the second half a year early. This undue haste might perhaps have been dictated unconsciously by a yearning for the pattern of history to be repeated. For many centuries, ever since Roman times, the second half of most centuries tended to be far more tranquil than the first half. In Washington, Mr. Truman got on both sides of the mid-century line with all the aplomb of a good politician. He told Congress early in January that "the state of the Union continues to be good," as it nears "the midpoint of the twentieth century." Later he spoke of moving forward into the second half of the century. He promised an infinitely better life for everyone, whichever side of the mid-century line, and reaffirmed his prescription toward that end: assistance for small businesses; more houses for the middle-income groups; tougher anti-monopoly laws, retention of rent controls; development of natural resources; better insurance against the hazards of old age, idleness and unemployment; better medical care and education, civil rights legislation; new labor relations law and production payments to support farm incomes. All this was to be coupled with suggestions on how to balance the budget. The bloody and confusing 1940's had brought to most men's minds a fear of the future such as they had not known for centuries, and Mr. Truman's objective is to temper that fear. Only time will tell whether the terminal point of such a philosophy would or would not belie the old English proverb citing inability to both eat and have a cake. Brave words to the contrary, the national budget persisted in sliding off into the red. The smell of further inflation was equally persistent. And just to impart a little more zip to the trend, the American Federation of Labor announced its intention of seeking "substantial" and "large" wage increases this year. The AFL forewarns of a business slump after June and a 10¢ an hr wage in¬crease for each worker "will be enough to reverse the prospective downward trend and start a rise." Thus it goes-"the way to halt a drop in demand for labor is to raise the price of labor." Elsewhere in the harassed world, beleagured individualists in New York achieved a local triumph of sorts for one of the freedoms denied by the Soviet and Nazi systems-the right of escape, some escape at least, from the servitude to decibels. Grand Central Station weakened perceptibly at Christmas on its 5-min commercials and bore down heavily on "Hark, The Herald Angels Sing," and on New Year's Day capitulated entirely by abandoning the broadcasting of canned music and slugs of advertising slogans. In Europe, M. Bidault's Assembly majority fell away and newspaper accounts of the incredible monstrosities of political trials beyond the iron curtain were supplanted by headlines marking the birth of Princess Yasmin. The latter was surrounded by Byzantine splendor but otherwise showed no apparent deviation from the accepted norm. In Western Germany, Dr. Adenauer began to speak up more boldly, and the whole fabric of Allied policy towards the defeated enemy further dossolved under the impact of rivalry with the Russians. In the Far East both the Americans and British seem somewhat embarrassed by Chiang Kai-shek's refusal to lie down. Dual thinking regarding the "squalid and useless struggle in the China seas" is such that newspapers give sympathetic accounts to an American ship running supplies to the Communists at Shanghai while calling for help for the recognized Chinese government in Formosa. And with Britain recognizing Communist China they may well have to team up with Russia against the United States to kick the Chinese representative off the UNO Security Council, the Far Eastern Commission and the Allied Council in Tokyo. Far Eastern policy has never been a bipartisan matter and as General Chiang retreated to his final redoubts in Formosa and Hainan, a number of Republicans pecked away at Administration lassitude. Senator Smith advocated the occupation of Formosa and Messrs. Hoover and Taft asked for use of the Navy. Mr. Acheson has stood firm, however, against military aid. None the less, a study will be made of the Generalissimo's chances. Mr. Truman has a private purse of $75 million for the Far East and some $94 million in frozen ECA funds. Mr. Truman will likely trade some of this money for support of new Marshall plan appropriations, always mindful, of course, of Mr. Acheson's plan to drive a wedge between the Chinese and Moscow, and his wish to avoid any revival of imperialist nightmares throughout the Orient. Mr. Acheson is very convinced that the victories of Communism in China will be short-lived and South Asia will not fall

Jan 2, 1950

By R. W. Sims

"He?s an SOB, but he's my SOB." Many of us have heard this line in reference to attorneys, and can appreciate the humor. However, the thought reflects a deeper attitude that lawyers should be used for attack purposes in the legal system or the regulatory process. Often, more permitting progress can be made with tact and flexibility than with inflexible, overly aggressive strategies. Usually, administrative hearings or other litigation work to the disadvantage of the applicant. Thus, I have concerns about approaching any permitting system with a hard-line attitude. On the other hand, the project team must always be prepared to defend permit applications and present a legally adequate case at public meetings, administrative hearings, or judicial proceedings. This paper discusses a number of strategies intended to increase the probabilities for successful permitting, whether opposition is informal or highly organized.

Jan 1, 1990

By Bjoern R. Petterson, Lars Haakon Siem

The world's longest highway-tunnel -- the Aurland Tunnel in western Norway -- is scheduled to be opened in the year 2000. A project to build a main highway between Oslo and Bergen with no ferry connections was approved by the Norwegian Parliament in January 1995. Construction of the five-year blasting project was started by the Norwegian Highway Authority in mid-March 1995, with an expected completion date of November-December 1999.

Jan 1, 1996

The annual meeting of the Woman's Auxiliary was held on February 19, at 10 a. m. The president, Mrs. Sidney Jennings, said in her greeting "it is a matter of congratulation that during the past year when the demands upon women for work of all kinds has been so large our membership has grown from the 50 enrolled at the first meeting a year ago to over 300 today. Some women, when. asked to join the organization, say that they are doing so much work in other ways that they have no time for work in a new organization, but the director for Canada struck the right note in her report when she told us of the splendid work the wives of mining engineers are doing in Canada, as individuals and as leaders and members of various organizations doing patriotic work. We do not want to divert such women from the work they are now doing, but we do want them to enroll as members of the Woman's Auxiliary and let us know what they are doing, that they play give inspiration to others." Reports were made by the directors of the following sections: Canada, Chicago, Colorado, Columbia, New York, Puget Sound and St. Louis, in some of which sections excellent progress has been made in food conservation, foreign war relief, including the adoption of fatherless French children, and in work for our own engineering regiments. These reports were read, accepted, and placed on file. The reports of the corresponding secretary, of the recording secretary, and of the treasurer, were read, accepted, and placed on file. Various amendments to the Constitution were proposed and accepted, and copies of the Constitution, as amended, will be mailed to all the members of the Woman's Auxiliary.

Jan 4, 1918

H. H. Stoek, Scranton, Pa. (communication to the Secretary): Mr. Rothwell's condemnation of my paper on the International Correspondence Schools as not giving an impartial view of the whole field of such enterprises, because it was confined to the description of a single one, might be legitimate if I had undertaken or professed to do anything else than that which I was requested by the Secretary of the Institute to do—namely, to give an account of this particular institution. This is a sufficient answer to all his direct or implied criticisms upon my omission to mention either persons or organizations outside of the special limits set for me. Recognizing fully that personalities have no place whatever in the Transactions, I regret the necessity of making the following statement in answer to Mr. Rothwell's charge that I omitted to give due credit to Mr. Ewald, a former principal of the International Correspondence Schools. The Colliery Engineer School of Mines was started in 1891, and its first student was enrolled October 16, 1891. During the fall of the same year the mine-mechanical course was laid out along the same general line that had already been followed in the mining course. This mine-mechanical course was the foundation from which sprung the later developments of the several mechanical courses. The latest circulars of information of the International Correspondence Schools give the following as their distinctive features: (1) courses of instruction for particular occupations,

Jan 1, 1900

By J. W. Parkinson

With most of the coal currently mined in the eastern U.S. already requiring cleaning to meet electric utility coal specifications, the question remains how medium- and high-sulfur coal producers will provide the even better quality coal expected to be demanded if pending acid rain legislation is enacted. One emerging approach is to crush the coal to liberate additional ash and sulfur so that better quality coal can be produced at equal yields. This paper discusses how to measure liberation. the premiums the utility market is willing to pay for lower sulfur coal, and a staged middlings crushing scheme that promises the benefits of total raw coal crushing but at lower costs. For some coals, cautious application of liberation concepts may be the only way to produce a product that can be quality and cost competitive in the future utility coal market.

Jan 1, 1988

By C. M. Brinckerhoff

Safety work in mining at the Andes Copper Mining Company, Potrerillos, Chile, is divided into three parts: (1) accident prevention, (2) fire prevention and protection, and (3) silicosis prevention and control. In the company's operations a steady campaign has been waged to reduce accidents and silicosis, and to prevent fires. In the following pages the safety record for the past twelve years will be examined and the methods explained by which the accident rate was reduced. Table 1 contains yearly data pertaining to the scale of the mining operations and the accident record. Block caving is used for all ore production and the tonnage mined has averaged 30,000 short tons per day for the past seven years. Table 2 classifies 44 fatal accidents which have occurred since 1935. The leading causes of accidental death are transportation of ore and use of explosives, followed in order by persons falling, falls of ground, and by asphyxiation. In the case of serious accidents, however, the greatest cause is falls of ground, followed, in turn, by ore transportation, persons falling, explosives, and asphyxiation. Accident Prevention The improvement of the safety record was obtained by a combination of many factors. In surveying the results at Andes for the past twelve years, it is possible to select some features of the present operation which have contributed to the accident record. The most important of these are: (1) good staff planning, (2) good equipment, (3) an alert safety organization, and (4) education and selection of the workmen. GOOD STAFF PLANNING As a result of good staff planning, the mine has good working conditions, namely, good ventilation, moderate temperatures and humidity, and good lighting. These factors not only reduce accidents but also improve efficiency. In haulage work, accidents have been reduced by having traffic move in a forward direction only. The latter makes possible a one-man train crew. Trains are centrally dispatched from loading drifts which are interconnected by signal lights, so that when a train in a lateral drift is given permission to move into a main line drift, a red light signals in all other lateral drifts in that area. Good track is maintained, and safety niches are required at all switch throws. Since safety niches were provided there have been no fatal or serious accidents at such points. All main line haulage drifts are illuminated by electric lights. Haulage drifts are kept clean. Adequate clearance has been provided between cars and between cars and the sides of the haulage drifts. The 4 1/2 ton Cranby type cars are equipped with roller bearings, and the 10 ton loconlotives with trolley shoes instead of wheels. These two features are responsible for improved ore haulage conditions and contribute to greater efficiency and safety.

Jan 1, 1950

The theme of the conference this year is diversification. One way to diversify is through acquisition. The principle underlying the winner's curse is that in competitive bidding situations where the value of the asset bid for is uncertain the winning bid will overstate the true value of the asset. The successful bidder is blessed with the winner's curse. What this paper will explore is to what extent this is true; how acquirers can avoid being blessed with the winners curse; and show how joint venture deal structures are used within the mining industry to avoid the winners curse.

Jan 1, 1996

By V. R. Bovino

You have afforded me the challenge of saying something profound in 20 minutes that will stay with you for 20 years. My hope is that from this presentation you will extract ideas that will move you? out of your offices, into the mine to seize upon the concepts that we will discuss. Your challenge is to transform those concepts into action and give life to the ideas discussed here. The notion of achieving limitless productivity produces peak levels of enthusiasm in today's mining leaders. Highly-productive mines do not happen by chance --they are created by progressive leaders. The quest for productivity improvement, exclusively through capital investment and technological advances, is an incomplete process. Improvement, through capital and technology, is often not achieved because we fail to energize the true potential and commitment in our employees.

Jan 1, 1991

By Terrence Chatwin, Michael Sweeney, Steve Accardo

Sutter Gold Venture excavated an exploration decline into a mineralized zone in the Sutter Creek gold mining district. Delays in obtaining the conditional-use permit resulted in 7 to 10 million gallons of water accumulation in the decline containing elevated dissolved arsenic. Sutter received a permit to land apply the water after reducing the arsenic concentration to 0.05 mg/L. Initially the water was treated by co- precipitation arsenic with ferric hydroxide. Operational difficulties of this treatment system resulted in Sutter pursuing alternative treatment methods. The activated alumina adsorpting was selected due to its flexibility and ease of operation. Operating and maintenance data and costs will be presented.

Jan 1, 1995

By S Amor, A Beasley

This paper provides an example of how industry can respond to the implementation of new regulatory approaches to mining risk, health and safety by adopting a robust, practical, software-based approach to the management of risk accountabilities in terms of competence, experience and suitability for obligations and responsibilities, as required in Queensland Coal Mining operations due to the introduction of Recognised Standard 22 (‘RS22’; Resources Safety and Health Queensland, 2021). Based on the authors’ experience from working with several Qld mine operations, it offers a snapshot of the experiences, approaches and reservations faced collectively by industry as a result of the introduction of RS22. Several challenges exist within the detail of RS22, leading to varied interpretations, implementation strategies and overall compliance between mine sites. Arguably the single biggest challenge identified has been how to find a balance between compliance and practicality – considering cost, operational interruption, available pathways for delivery of competence, ongoing compliance and value adding to the business operations and people. Software-based solutions are increasingly being relied upon to address the introduction of new regulatory approaches and the significant administrative load placed on mining operation Site Senior Executives (‘SSE’) due to RS22 means this case is no different. This is further complicated given the continuous, ongoing changes with the site management structure witnessed by the authors across each of the mining operations as a result of continuous changes to personnel, the site risk profile and an overall mining industry uncertainty of how to respond to RS22. The stringent reporting/notification requirements under legislation compounds this further. The approach put forward by the authors is a well-considered rationale and approach to the application of training and skilling; and equally how to ‘future proof’ the coordination of site training needs around changes to the Management Structure, the Risk Register, skilling processes and succession planning. A brief investigation of other legislative frameworks concluded this approach would likely meet or exceed expectations of jurisdictions across Australia and overseas, making this a highly flexible approach for establishing a competent Management Structure to provide safe systems of work.

Apr 16, 2024

By P. K. Ray, Sudip Kumar Koley, Sainath M. Reddy, Devulapalli L. S Rasagna

Bangalore Metro Rail Project- phase II is one of the technological challenging project, particularly construction of underground metro rail system. The Bengaluru city is very congested area and connecting metro rail system with existing transportation networks is equally challenging. In this phase-II, the Underground metro is being constructed by blasting hard rock formation and supporting the shear zone. Most of the subsurface rock formations comprise of granitic Gneissic formations are of Precambrian age and shear zones that includes friable a thin weathered rock formation. With such subsurface geological conditions, , the anticipated construction challenges include : A) deep excavation of hard rock mass under old and sensitive structures and buildings, by controlled blasting; B) variation in the rock grade from grade I to grade V; C) weak rock mass at shear zone resulted in planar failure beneath the retaining wall; D) water seepage along shear planes; E) selection of a suitable method to conducted blasting near high voltage electrical machinery or power cables. This paper describes the methods adopted to mitigate these technological challenges and to meet stringent environmental compliances. These includes study and application of various geological, geotechnical parameters to develop a proper line drilling and controlled blasting techniques to minimize the ground vibrations and controlling the rock fragmentation and to optimize the equipment performance in terms of productivity and time schedules. The “Phase 2” software of “Rocscience” has been used and Regression analysis has been carried out by using MCD (Maximum Charge per Delay) and PPV (Peak Particle Velocity) to estimate with FOS (Factor of safety) for sensitive places such as nearby high rise buildings and electrical transformers.re.

Sep 1, 2022

By Paul Riches

LR Process Expert is a cost-efficient process automation system for all types of long rolling mills, including, rod, bar, section, rail, reversing mills, and flat blocks. The system performs a wide range of tasks for optimized operation – from suggesting pass schedules to calculating and downloading optimized mill settings according to the availability of rolls. LR Process Expert also monitors and collects data from the raw material stage through to the finished product. It delivers valuable mill reports to the operator staff and management so they can easily assess a plant’s performance and optimize production. Defined Key Performance Indicators (KPIs) help to assess a plant’s performance; this system is not limited to one plant but can enable plant-toplant performance at corporate level.

Aug 16, 2017

By T. N. McVay

The Bureau of Mines has developed a field test for detecting the presence of columbium in a variety of minerals containing the clement. The test consists of fusing the mineral or rock powder with potassium pyrosulfate in a porcelain crucible, digesting the melt with hot dilute hydrochloric acid to release the columbium oxide (Cb205), and subsequently reducing the columbium oxide to a lower oxide by adding tin, which gives a blue color to the contents of the crucible. The method will detect 1 percent of contained columbium oxide (Cb205) in a mineral sample provided no tungsten is present. If a mineral containing appreciable titanium is test,-!d in the same manner, the solution in the crucible becomes violet. In the presence of columbium, titanium at first causes a violet coloration of the solution, which after a few minutes is masked by the stronger blue of the reduced columbium oxide. Although tantalum oxide (Ta205) does not interfere with the columbium test, tungsten gives a blue color that is indistinguishable from the color obtained with columbium. A simple method is available to detect the presence of columbium in the absence of tungsten, but when the presence of tungsten is suspected, the sample must be subjected to somewhat more elaborate chemical tests to determine the presence or absence of columbium. Although these latter tests can be made in the field, several steps are involved that arc best performed in the laboratory with simple equipment.

Jan 1, 1962

By C. S. Parsons

Introductory The steady advance in the price of lead and zinc in the metal markets of the world during the past few years has resulted in an active search for new deposits of these metals, and to the re-examination of known properties that are now idle. There are a number of deposits of these metals in eastern Canada, the best known of which are the Tetreault mine at Notre Dame des Anges, Que.; the Reader mine on Calumet island, Que.; the Stirling property in Cape Breton, and the Federal mine in Gaspe district, Que. . The author has run concentration tests on the ores from the first three mentioned properties. The ores from Notre Dame des Anges and Calumet island presented problems in concentration which were not successfully solved until the past year. Although considerable experimental work has been done by the Ore Testing Laboratories on the ore from the Stirling mine we have not been successful in developing a satisfactory method of treatment. Character and Types of Ores Metallurgically the lead-zinc ores of eastern Canada may be classified into three distinct types as follows: First: - Ore in which the sulphide minerals are fairly coarsely crystalline and can be freed by crushing to 40 or 60 mesh. The zinc blend has a high iron content (not marmatite) and gives a dark brown colour on grinding. The ores of Notre Dame des Anges and Calumet island, Que., may be cited as examples.

Jan 1, 1925

By Steven Keim, Steven Stansfield, Kevin Andrews

Geotechnical, geological, and hydrogeological fieldwork and data collection for the mining industry is often conducted by younger, less-experienced staff members. In many cases, fieldwork personnel are recent college graduates or are otherwise relatively new to the mining industry. Due to busy schedules, staffing shortages, project budgets, and in some cases, poor management, new fieldwork hires often do not receive thorough training. In the past and the present, many workers in the mining industry learn(ed) by “doing.” While this is still considered to be the most practical approach and the easiest way for a company to determine the skill set of an employee, there is always some risk involved in the “feet to the fire” method. The reality is that field personnel are often collecting data on which major operational decisions will be made or on which regulators will base enforcement decisions. Inadequately trained or inexperienced field personnel may collect inaccurate data or fail to recognize key conditions that may influence decisions made by regulators, design engineers, mine managers, and corporate leaders. Even the best engineers may come to incorrect conclusions if they are starting with poor input data. Decisions based on inaccurate data often result in delays, budget issues, unsafe conditions, or even worse consequences. This paper provides numerous mining industry examples of incidences where inaccurately collected field information did, or could have, resulted in major adverse consequences. The paper also offers some simple approaches to minimizing the potential for such problems.

Jul 1, 2023

By Sean Hillacre, Arthur Lieu

NexGen’s approach to uranium processing design including the crushing/grinding and leaching of raw ore through to yellowcake precipitation and tailings management focuses on minimizing surface footprint, freshwater consumption, and human radiation exposure. Applying the concept of best available technologies economically achievable (“BATEA”), NexGen continues to research, evaluate, test and validate various advanced technologies that can be incorporated into the Project design, including distinctive tailings storage techniques. Additionally, NexGen is proposing that tailings generated from the mill processes be used as cemented paste backfill of stopes, as well as stored in a purpose-built, Underground Tailings Management Facility (“UGTMF”) comprised of several dedicated chambers. The paste backfill method of tailings storage is used globally, however, constructing purpose-built tailings chambers in waste rock is a new concept in uranium mining, which would typically be cost prohibitive for most projects given the expense to develop non-economic material for the sole purpose of storing tailings. The Rook I Project is uniquely positioned to implement the UGTMF due to robust Project economics and favourable technical setting which provides NexGen with the opportunity to set an elite standard for tailings management. When compared to conventional surface tailings management facilities, storing tailings underground as cemented paste reduces geotechnical, geochemical, environmental, and human health risks associated with tailings management. Additionally, the UGTMF vastly reduces the area of surface disturbance and allows for progressive decommissioning during the life of mine operations.

Jan 1, 2020