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By Henning Schwarz, Ade Ogunsola, Anas Almousa

"The Riyadh Metro, commissioned by Arriyadh Development Authority “ADA” - the executive arm of The High Commission for the Development of Arriyadh -, forms part of a new public transport-system of Saudi Arabia’s fast growing capital city. The Design & Build project consists of 176 km of Metro Line with 57 km of tunnels. Beyond the Design and Construction, an additional aim of the ADA is to introduce up-to-date methodologies and improve safety in construction projects. A systematic dilapidation survey of buildings and infrastructures was a prerequisite for designing the required instrumentation and monitoring tools. Site investigations required of existing methodologies and the use of geophysical methods for achieving reliable results. Large diameter TBM tunneling is challenging in hot weather conditions and karstic ground. The present paper shows how modern technologies for underground construction are introduced into the local industry and gives an outlook on future projects in the Kingdom of Saudi Arabia. INTRODUCTION Riyadh, the capital city of the Kingdom of Saudi Arabia, is a fast growing city with more than 5.7 million inhabitants. The growth of the city is linked to the recent history of the Kingdom, where some initial milestones from the 1950’s can be highlighted: Revenue generation from the exportation of oil from the Kingdom; downstream investment of oil revenue in the reconstruction and development of the Kingdom; a general plan for the settlement of the Bedouins; the provision of a public electricity network for the city; the opening of the Riyadh - Dammam railway corridor providing a link from the capital to the Eastern Region; the commissioning of Riyadh airport (converted to Riyadh airbase, after the opening of King Khalid International Airport in 1983); and the relocation of ministries and other central government agencies in 1955. In 1974, The High Commission for the Development of Arriyadh was established as the organizational, planning, executive and coordinating body responsible for the development of Riyadh. Arriyadh Development Authority “ADA”, established in 1983 is the High Commission’s executive, technical and administrative arm. The ADA is responsible for implementing the High Commission's organizational, planning, executive and coordinating decisions and missions. The ADA’s president is a member of the High Commission (ADA 2015). One of the remits of the ADA is the preparation and execution of a transport plan for the city of Riyadh."

Jan 1, 2016

By R. B. Dunn

Whilst coalmining in the United Kingdom has been synonymous with longwall mining practice there have been changes in recent times which have enabled not only an extension in the length of the face to be worked but also in the ability to extract both thick and thinner seams. Additionally the industry has taken a positive view in the extension of retreat methods of extraction applied for different reasons both to particularly thick and specially thin seams. To permit development of a flexible programme to meet these diverse needs, it has been necessary to design machinery along with mining systems specially suited to these requirements. In reviewing current UK thinking special emphasis is made on the extraction of thinner seams generally of higher quality coal at moderate depths with a commentary on some recent results.

Jan 1, 1979

By Shakuntala Tudu, Indrajit Paul, Surajit Sinha, Pulibandla Basaveswara Rao, Shaik Mahaboob Basha, Srinivas Dwarapudi

The iron and steel manufacturing sector directly accounts for 7–9% of global CO2 emissions. Raw material preparation, such as iron ore sintering, pelletizing, and cock making, is the major CO2 emitter. As climate change becomes a bigger concern, steel manufacturers need to lower CO2 emissions without hindering efficiency or increasing costs. In recent years, the percentage of iron ore pellets in blast furnaces has increased due to its uniform size, good reducibility, and high tumbler index. Pelletizing is energy-intensive and emits considerable CO2. Around 20% of CO2 emissions during pellet making come from fluxes. In the present work, the authors established a novel CO2- free flux called wollastonite (CaO.SiO2) for sustainable palletization. Pellets with varying percentages of wollastonite (0–6%) are prepared and tested for chemical, physical, and metallurgical properties. Image analysis through an optical microscope is carried out to quantify the phases of fired pellets. SEM–EDS is performed to evaluate the chemical composition of the melt and slag phases. The results showed that the reducibility index (RI) and swelling index (SI) of pellets decreased with an increase in wollastonite dosage. Pellet strength increases with an increase in wollastonite addition up to 1.2% CaO (2.27% wollastonite), and a decrease in strength is observed thereafter. The increase in strength is attributed to the increase in slag bonds. The decrease in strength beyond 1.2% CaO is mainly because of an increase in low melting eutectics and more magnetite content. Pellets with 2.27% wollastonite to get 1.2% CaO showed good physical and metallurgical properties.

Mar 4, 2024

John C. Greenway was responsible for much of my success in the seven years from what I called the end of my apprenticeship in exploration until I entered the Army in World War I. I first met Green- way on my return from Promontorio and, as he was replacing Powell, he was to be my boss. Even at first glance you couldn't help liking and trusting him. He was tall, well built, and erect-an old Yale athlete. After college he became a captain in the Rough Riders and a friend of Theodore Roosevelt, distinguishing himself in the Cuban campaign. He made good friends in all ranks of the Rough Riders, some later becoming leaders of industry and others following Greenway where-ever he went. After the Spanish War Greenway worked for iron mining companies around the Great Lakes and when the directors decided that Calumet and Arizona needed a new manager the ones who were also prominent in Oliver Iron Mining Co. selected Greenway It was a lucky choice for Greenway and for me. He became the best manager among those who ran the big copper mines He was open-minded in encouraging discussion and even opposition-until he made up his mind. Then, in military fashion, everyone must follow his decision without question. I think this is an essential of good management. Unfortunately a few did not feel this way and they had to leave. It was characteristic of those times that respect for the boss was so great that in the 16 years in which he was one of my best friends I, like all under him, always called him "Mr. Greenway." Soon after he arrived Greenway asked the leading mine operators in the southwest, Dr. Louis D. Ricketts and James S. Douglas, son of the Dr. James Douglas who had made Phelps Dodge great, to do special work for Calumet and Arizona. I found later that the object of the study was to determine the terms on which the half-dozen Warren District properties of Calumet and Arizona were to be joined in one

Jan 1, 1976

By Z. Hyder, M. Karmis

Underground or In-situ Coal Gasification (UCG or UICG), though not a new concept, is now attracting considerable global attention as a viable process to provide a "clean" and economic fuel from coal. Applying improved UICG technology to gasify deep, thin, and low-grade coal seams could vastly increase the amount of exploitable reserves. However, it is imperative that further development of this technology is based on integrating UCG practices and potential environmental impacts with accepted sustainability frameworks and processes. This paper evaluates the potential of UCG to conform to frameworks such as MMSD (Mining, Minerals and Sustainable Development), Natural Step and Green Engineering, in order to define its "sustainable" potential. The paper also discusses the potential contributions of UCG to sustainability during its design, operation, closure, and post-closure phases.

Jan 1, 2011

By I. M. Ahmed, R. S. Hassan, M. I. Aly

Extraction and separation of La, Sm and Dy ions from acidic sulfate-phosphate solutions was investigated using a cation exchange extractant, bis(2,4,4-trimethylpentyl) phosphinic acid, CYANEX 272, in kerosene. The influence of shaking time, equilibrium pH, extractant, sulfate and phosphate ion concentrations, diluent type and temperature was studied. The extraction was found to be pH-dependent, and increasing the phosphate ion concentration inhibited the extraction which was found to be endothermic. The stoichiometry of the extracted metal species was found to be MOH.H2OHSO4H2A.A2. Aliphatic diluents were found to enhance the extraction compared to aromatic diluents. The results showed that there was a separation mode between the metal ions when varying the hydrogen ion and sulfate ion concentrations, under the used experimental conditions. The investigated process was used for the recovery of La, Sm and Dy from the acid solution resulting from the leaching of low-grade monazite.

By F. G. Miller

It is generally accepted that sulfur exists in coal in three forms: (1) pyritic, (2) organic, and (3) sulfate sulfur. Sulfate sulfur usually makes up less than 1% of the total sulfur content. Pyritic and organic sulfur, make up almost all of the total sulfur and occur in varying amounts in different coals and can vary greatly in coal of the same seam Pyritic sulfurs of 20% to 80% of the total sulfur have been reported Other authors have shown that it is not possible to remove the organic sulfur without chemically altering the coal. Chapman and Jones (1) state: "Organic sulfur, unlike pyritic sulfur does not exist as discrete particles, but is intimately associated with the coal structure, and as such it is not possible to remove it or reduce its concentration by physical means." Any success in removing sulfur has come about by removing pyritic sulfur by physical means; therefore, removal of sulfur in the pyritic form is the subject of this investigation. The extent to which any impurities can be removed from a particular coal can be determined by a washability study. Outside of crushing coal, to finer sizes or chemically altering the coal, there are no known methods of changing this inherent washability characteristic. The efficiency of various methods used to remove impurities can be determined by comparison of results produced at a yield to the results as shown by a washability study. In recent years heavy media processes have proven their ability to wash plus 28 mesh coal and nearly produce results shown to be theoretically possible by the washability study. Therefore, it is the objective of this paper to show various methods of treating the finer fractions of the coal, in the hope of developing a process, which can effectively produce in the fine fractions the efficiency of heavy media devices in the coarse.

Jan 1, 1963

By Lianhui Jia, Yali Han

"The key technologies of a large rectangular pipe jacking machine with dimensions of 10.12m × 7.27m (width x height) include selection of rectangular cross-section cutting modes, analysis on the strength and stiffness of the rectangular shield, integrated control of electro-hydraulic proportional thrust systems and ground conditioning for excavation are presented in detail in this paper. These key technologies have been successfully applied and verified on site during tunneling, providing a new concept for the building of large rectangular traffic and pedestrian tunnels in urban areas for the future.1 INTRODUCTIONIn the past, underground tunnels were mainly used for drainage, sewage, utilities, metro tunnel, etc. and most of them had circular cross-sections. Recently, as a result of economic development, gradually accelerating urbanization process and diminishing ground space, underground tunnels have already become a new trend for urban underground space utilization. Due to the heavy traffic flow, the demands for rectangular cross-section underground tunnels, such as pedestrian underpass and road tunnel, are increasing gradually.The Rectangular pipe jacking machine (hereinafter referred to as RPJM) was firstly developed in Japan for the construction of metro station, pedestrian underpass, underwater tunnel by-passes, etc. Kazunaki Kawai et al. introduced a RPJM developed and manufactured by KOMATSU in 2002 [1]. Tosikazu Kubota et al. confirmed the rectangular tunnels’ superiority to circular tunnels with regard to larger inner cross-section and lower construction cost in their RPJM construction reports [2]. Compared to circular pipe jacking machines, a RPJM also has the merits of a higher inner tunnel space utilization ratio and is able to excavate in shallow overburden areas. As shown in Figure 1, the effective area of a rectangular tunnel is more than 20% higher than that of an equivalent circular tunnel."

Jan 1, 2016

By K. Verghese

Neutron capture prompt gamma-ray analysis provides the best method for on-line analysis of the elemental composition of large volumes of bulk material. This paper summarizes the Monte Carlo models which simulate the radiation transport within two such analyzer systems; namely, the borehole configuration and the conveyor belt configuration. The models are useful in the design optimization of the analyzer systems, in minimizing the amount of experimental calibration data for calibrating these analyzers, and in investigating the detection sensitivity for different elements. The computational scheme in these models is made extremely efficient by the use of various powerful variance reduction methods and by efficient data management. Experimental verifications of the two models carried out in the laboratory indicate very good agreement with the Monte Carlo results.

Jan 1, 1984

By Robert D. Coale

This paper will describe the copper concentrate slurry pipeline and pumping system between the concentrator and the port at Bougainville Copper Ltd. The operations of Bougainville Copper Ltd. are located on the island of Bougainville in the South Pacific. Geographically, it is the northernmost island of the Solomon Group but, politically, it is part of Papua New Guinea. Papua New Guinea is a United Nations Trust territory administered by Australia, having recently been given self-government, with independence scheduled for December 1974. (Fig. 1). The island is approximately 130 miles long by 30 miles wide, with the Crown Prince mountain range forming a spine along its length. The mountains in place are over 8,000 feet high with the mine located on the western flank at an elevation of 2,200 feet. Exploration on Bougainville for copper by Conzinc Riotinto of Australia (CRA) began in 1963 and by 1968, through geophysical, geochemical and diamond drilling methods, an orebody containing nearly one billion tons of ore grading approximately 0.48% Cu. and sane gold had been outlined. Bougainville Copper Ltd., the company operating the mine, is 53.6% wined by CRA, 20% mined by the government of Papua New Guinea with the public Folding the remainder of the shares. The first copper concentrate was produced in early 1972, with production for the first full year, 1973 being:

Jan 1, 1974

By P. D?Elia

Following a study by NIOSH on the availability of teams in the U.S. as well as existing training sites and their capabilities, the Penn State University, leaders of the Pittsburgh Section of SME, providers of mine rescue equipment, and industry sponsors united to establish and make fully functional a student mine rescue team at Penn State University. With the growth of MERD and mine rescue competitive events at Missouri S&T, the Mine Training and Technology Center in PA, and at Colorado School of Mines Edgar Mine, a critical mass of effective training venues were made available to help student teams progress and develop mine rescue skills. The challenges to be met in creating and developing a student mine rescue team will be discussed. The rewards from this type of effort will be the quick capability of graduates from mining engineering programs to be involved in not only mining operations, but industry mine rescue teams and other leadership roles as well.

Jan 1, 2012

By S. K. Oraee

Most management decisions at all levels of the organization are as directly or indirectly depends on the circumstance of future. With regard to predict the future events in the process of decision-making plays a main role, therefore, forecasting is very important for every organizations and institutions. There is a variety of methods to predict time series. In general, these techniques can be divided as following: statistical, artificial intelligence and analytical techniques. Two of the most common methods for time series prediction is autoregressive integrated moving average (ARIMA) and artificial neural network (ANN) methods, these methods are the subset of statistical and artificial intelligence techniques respectively. In this paper, a hybrid model of ARIMA and ANN models are employed to predict the number of fatal injuries in the USA underground coal mines. This research showed the result of hybrid model is better than split model.

Jan 1, 2011

The design/optimization of the pump and cyclones to maximize grinding circuit efficiency first requires a concise understanding of, and clearly defined specifications for, desired grinding circuit performance. Subsequently, the pump and cyclone performances that provide the desired grinding circuit performance can be defined. Once the performance requirements of each process unit are determined, selection of physical equipment parameters that will deliver those performances can be carried out. The Functional Performance Equation shows that there are two distinct efficiencies in closed circuit ball milling. One of these, ?Circuit Classification System Efficiency? (CSE), is the fraction of ?coarse? material inside the ball mill upon which grinding energy is deliberately expended, versus the remaining fraction of ?fines? or finished size material inside the mill, upon which grinding energy is wasted (on over-grinding). The role of the pump and cyclones is to maximize CSE, which is the desired grinding circuit performance. The obtainable, target CSE for any given circuit can be estimated, for example by referring to a plant data base of CSE?s. Design/optimization guidelines then allow us to specify the pump and cyclone performances that will achieve the target CSE. This paper outlines the step-by-step, systematic method of pump and cyclone selection which maximizes CSE. Numerous examples of its successful application are provided.

Jan 1, 2011

By J. Haynes

Coal mines in the eastern US often use sloped shafts as production beltways for ore removal, as means of access for supplies, and for ventilation. These structures are usually completed with the help of a contractor. In late 2011, Frontier-Kemper Constructors was engaged to build a slope for a coal mine in southern Indiana. Although the site was located in familiar Illinois basin formations, the geology proved to be very difficult. This paper describes some of the challenges faced during excavation of this slope and the methods used to overcome them, including changing the method from conventional drill and blast to cutting with a continuous miner.

Feb 27, 2013

By K. E. Kolm, W. H. Langer

Developing natural aggregate resources (sand, gravel, and stone) creates environmental impacts. A systems analysis method has been designed to characterize the components of the environmental system, identify potential impacts to those systems, and evaluate the extent of those impacts. The step-wise method consists of problem definition, data collection, preliminary conceptualization and characterization, additional data collection, data analysis, and refinement. The method requires analyzes of various systems making up the environment, including land surface, geomorphic, subsurface, and groundwater systems. After system characterization is complete, the method focuses on identifying and evaluating potential environmental impacts to determine acceptable mining strategies.

Jan 1, 2001

By S. -Y. Hwang

An ongoing problem for industry in Korea is effective removal of heavy metals from and safe disposal of spent power plant fly ash. This research endeavor attempts to develop selective separation of Ni from leach liquor using a selective chemical precipitation method. The research was conducted by changing two variables, the pH and the concentration of ions in solution. The effect of other ions present in the system on the separation efficiency of Ni species was also investigated by adjusting OH and NH3 concentrations. In the pH range of 7-9, the chemical precipitation method produced a high yield of Ni by precipitation from the fly ash leach liquor.

Jan 1, 2010

By G. Rainville, I. Servi, F. Katrak

Despite the severe drought conditions that reduced farm requirements for industrial mineral products, most industrial minerals markets in 1988 continued their growth or, at worst, remained flat. Earlier projections of output declines did not materialize in most segments. Preliminary estimates of demand in Europe and Asia show strong growth for most industrial minerals. Profitability in industrial minerals in North America was best in those minerals that had a significant export market or were not strongly regional. Growth and price trends in the more regional industrial minerals markets in the US such as sand and gravel, crushed stone, and cement, more closely followed the broadly disparate regional economic conditions. For example, sand and gravel and crushed stone grew strongly in the Pacific Coast and northeastern markets but not as much as in the Southeast. Total growth for sand and gravel in 1988 is projected at about 3% above 1987 levels. Combined production is up about 27 Mt (30 million st) to 2 Gt (2.2 billion st). Following the relentless trend of foreign acquisition of US cement companies (currently about two-thirds are owned by foreign interests), several aggregate operations have been purchased by foreign companies. Notable among these in 1988 was the acquisition of Rinker Materials Corp. by CSR of Australia. The acquisition of this Florida-based aggregate and concrete operation will expand the current holdings of CSR in the southeastern US, with operations consolidated under the Rinker logo. In addition, Pike Industries of New England and J.L. Shiely Co. of Minnesota were significant aggregate producers that were acquired by foreign firms. New England's only cement manufacturer, Dragon Products, was acquired by a subsidiary of Cementes del Norte of Spain. Dravo continued to expand its influence in the lime and limestone markets. It became the major supplier of construction aggregates on the inland river system with its purchase of Cyprus Minerals' limestone aggregate operations in Kentucky, Louisiana, and Texas. Although lime production continued to grow from 14 to 15 Mt (15.7 to 16.7 million st) in 1988, lime imports decreased for the fifth consecutive year to 145 kt (160,000 st). In the more export-oriented industrial minerals markets, performance was generally very good for 1988. Soda ash enjoyed an excellent year, with its price up to $102.50/t ($93 per st). This reflected the tight market situation for soda ash, particularly in late 1988. Soda ash production in 1988 was 8.6 Mt (9.5 million st), reflecting the industry's improved efficiency. Particularly significant was the increase in caustic soda prices that led to increased substitution by soda ash. The export market remained at 2.1 Mt (2.3 million st). Phosphate production recovered to the 42 Mt (46 million st) level, a 12% increase despite a soft export market. The price, however, remained soft throughout the year. W.R. Grace sold its interest in its Florida phosphate mine and its phosphoric acid complex as part of its divestiture of the agrichemicals business. The strengthening of the major producers has continued as lower cost capacity has been idled. Future permitting of phosphoric acid facilities and development of reserves will be necessary to maintain current production levels beyond the mid- to late 1990s. Despite new developments worldwide in the titanium minerals market, strong demand has continued to apply pressure to price, with concentrate and slag prices going up. The demand for high quality slag as feedstock for pigment production has resulted in process improvements in South Africa (Richard's Bay) and in plans by Canada to import high quality ilmenite by 1991 to produce a 90% TiO2 slag. Although growth in industrial silica sand applications was small in 1988, concentration in the industry continued. Unimin continued to acquire silica operations. Unimin is now the nation's leading producer of granular silica. The end users of silica have consolidated further. Owens-Illinois purchased Brockway Inc., a leading container glass producer. Three companies now control 75% of the container glass industry. ECC continued to be an aggressive purchaser of industrial minerals operations throughout the world. It acquired Cyprus Minerals' calcium carbonate business as well as two operations in Italy. In addition, ECC continued its aggressive acquisition of kaolin (Australia) and aggregate producers. 1988 was a good year for industrial minerals markets worldwide. More importantly, though, it was a year that showed continuing consolidations of reserve ownership in the industry around the world. Barite AN. Castelli, Baroid Drilling Fluids Inc. US mine production of barite decreased 9.4% during 1988. Consumption (sold or used by grinding plants) increased by 37.9%. Imports are estimated to have increased by 21.2%. World mine production decreased by 9.8%, according to the US Bureau of Mines. The value of domestically produced barite, fob mine, decreased 4.6%, according to the Bureau. The declared value cif US port of all imported ground barite during the first 10 months of 1988 increased from $37.16/t ($33.71 per st) in 1987 to $37.92/t ($34.40 per st), according to Bureau figures. Nevada continued to be the leading producer of barite with 72% of the total, followed by Georgia and Missouri. The Bureau of Mines estimates 69% of US mine production was used as a weighting agent in drilling fluids. The other 31% was used in barium chemicals, glass, or as a filler. Most of the production from Missouri, Georgia, and Tennessee was used in the non-oilfield sector. Of the total consumption used by grinding plants and chemical manufac-

Jan 1, 1989

By Peter McKenna

Different reefs being extracted from a mine will, in all likelihood, have significantly different semi-variogram models - and these will probably vary from geozone to geozone. As errors of estimation are dependent on the semi- variogram parameters, it follows, if a mine samples all reefs in all sections using the same sampling grid pattern, that estimation errors (or limits of confidence) will not be the same throughout the mine. This may be an undesirable situation! A geostatistical study of the relative merits of alternative sampling arrangements has been carried out by considering different reefs in different sections of a South African gold mine.

Jan 1, 1989

By Konstantinos Komnitsas, Evangelos Petrakis, Emmanouil Varouchakis

The paper discusses the limitations of population balance modeling (PBM) in predicting particle size distribution in grinding systems. It introduces a nonlinear framework that transforms the batch grinding equation into the Rosin-Rammler distribution, providing more accurate analysis under different operating conditions. The study uses marble as test material and investigates the adaptability of the nonlinear model with different media sizes.

Oct 1, 2023

By D. Mohapatra

The possibility of using 2,2,4-trimethyl-1,3-pentanediol dissolved in tetrachloromethane as extractant for boron recovery is discussed. The parameters optimized for this purpose are contact time, boron concentration in the aqueous phase, extractant concentration, equilibrium pH and phase ratio. NaOH is used as stripping agent for boron recovery from the loaded organic phase. Boron extraction is found to be a slow process (equilibrium time 20 minutes) compared to boron stripping, which is reasonably fast (equilibrium time 5 min). Maximum boron extraction is possible at a broad pH range from 1.0 to 6.0. Using 1.0M extractant concentration, a 1:1 phase ratio (organic: aqueous) and two stages, ~99% boron extraction is achieved. More than 97% boron stripping is possible using 0.5M NaOH at a 1:1 (organic: aqueous) phase ratio in two stages. Overall, a 95.6% boron recovery was achieved. Loss of solvent into the aqueous phase and co-extraction of Ca, Na and K into the organic phase at higher equilibrium pH are two major concerns in his process.

Jan 1, 2008