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By Steven A. Savage

Agrico Chemical Company, as we presently know it, is the result of the coming together of several different fertilizer operations. The Williams Companies, our parent organization, first entered the fertilizer business in 1971, when it acquired the fertilizer operations of the Gulf Oil Company. This gave us, among other things, the manufacturing facility at Donaldsonville, Louisiana. In 1972, The Williams Companies acquired Agrico Chemical Company from Continental Oil Company, bringing in a manufacturing facility and phosphate mines at Pierce Florida. Our Florida Mines are in the region commonly known as the Bone Valley Region of Florida. The majority of the phosphate fertilizer produced in the United States utilizes rock mined in this region. The Donaldsonville Plant was originally built in 1967-68 on the site of the old Faustina Plantation at an approximate cost of $80,000,000. (This plant is commonly referred to as our Faustina Plant.) Until such time as Agrico was acquired from Continental Oil, the Donaldsonville Facility was solely used to upgrade phosphoric acid into finished granular products.

Jan 1, 1986

By M. F. Martin

Dewatering aids are chemicals which enhance the efficiency of mechanical dewatering equipment such as vacuum disc filters and centrifugal dryers. A new dewatering aid has been developed which significantly lowers the moisture content of the mineral concentrate and causes none of the undesirable side effects normally associated with dewatering aids. Highlights of product development from laboratory screening through field testing will be discussed.

Jan 1, 1985

By Scott O’Brien, Richard Williams, Camilo I. Mejias, Elias Godoy, Javier Sierra

High-rate thickeners play a critical role in tailings management by enhancing water recovery and increasing solids concentration. However, these units face operational instability due to fluctuations in feed solids, flow rate, and flocculant response typically managed in manual mode with delayed corrective actions. This work presents an adaptive automatic control algorithm designed for dynamic thickening environments. The algorithm integrates real-time measurements of feed density, rake torque, bed level, and turbidity (overflow), optimizing the underflow slurry density while minimizing suspended solids in the overflow. The proposed control strategy is modular, simple, scalable, and applicable to both existing and new thickening systems, offering a robust alternative to manual operation in increasingly demanding metallurgical environments.

Feb 22, 2026

By Christopher E. Dianora, Matthew Sorrell, Eileen Test

"Constructed between 1939 and 1945, the Rondout-West Branch Tunnel (RWBT) portion of the Delaware Aqueduct is 45 miles (72 km) long. The New York City Department of Environmental Protection (NYCDEP) first identified suspected areas of leakage from the RWBT in the 1990s. A $1 billion project is underway to mitigate the leakage through the construction of a bypass tunnel around the area of most severe deterioration, a 2.5-mile (4 km) section located beneath the Hudson River. Two shafts, 800 and 900 feet (244 and 274 m) below the ground surface, are being sunk to support the tunnel construction. The deep shafts will be subjected to high groundwater pressures and have been designed to accommodate multiple tunnel portals. This paper discusses the engineering decisions and analyses leading up to the final design. INTRODUCTION Project Background The New York City Department of Environmental Protection (NYCDEP) provides over 1 billion gallons (3.7 billion liters) of water to over 9 million residents of the City of New York and surrounding communities each day. This water is stored in upstate reservoirs and conveyed to the City via a system of aqueducts and tunnels. Water is delivered to the City almost completely by gravity and consists of three systems: the Croton, the Catskill, and the Delaware. The Delaware System is the largest of the three and supplies between 50% and 70% of the City’s daily water supply. In the 1990s, the NYCDEP discovered leaks in the central 45-mile-long (72 km) portion of the Delaware Aqueduct known as the Rondout-West Branch Tunnel (RWBT). The leaks release between 15 and 35 million gallons per day (MGD) (132.5 million liters per day) and are concentrated in two areas near Wawarsing and Roseton, New York. As part of the Rondout-West Branch Bypass Tunnel and Wawarsing Repairs Project (Bypass Tunnel Project), the leaks in the Wawarsing area will be repaired by grouting from inside the existing RWBT, and the leaks in the Roseton area will be mitigated by constructing a bypass tunnel parallel to and 1,750 feet (533 m) north of the leaking portion of the existing RWBT. Two deep shafts will be excavated on either side of the Hudson River: Shaft 5B in Newburgh and Shaft 6B in the Town of Wappinger."

Jan 1, 2016

By K. Boakye, T. Newman, P. Bláha, M. B. Toelle

"This paper presents a quarry optimization plan using a block model and an in-house development quarry scheduling and optimization software (QSO Expert) to help improve quarry operations at Crystal River. The Crystal River Quarry is an underwater quarrying operation that barges limestone via the Gulf of Mexico, as the main source of raw material to a cement plant in Theodore, Alabama. To improve the quarry operation, an evaluation was completed to optimize the quarry planning and extraction procedures of the quarry. In order to achieve this, additional exploration drilling campaign was implemented, a new block model was re-calculated and the latest version of QSO Expert software was used. The primary economic impact is a higher recovery of limestone reserves; sustainability of resources, corresponding longer quarry life. Secondarily as the limestone is mined underwater and stockpiled above water, drainage reduces moisture content achieving direct cost reduction on limestone shipping. In addition, a considerable reduction in operational cost was achieved due to a significant decrease in consumption of electrical energy, reduced dragline maintenance costs and reduced dragline movements within the operation. INTRODUCTION Holcim is a Swiss-based global building materials and aggregates company. Founded in 1912, the company expanded into France and then throughout Europe and Middle East during the 1920s. In 1922, Holderbank, as the company was then known, expanded beyond the Swiss borders into France. By the end of the decade Holderbank held stakes in Belgium, Germany, the Netherlands, and Egypt (Holcim History 1912-2012) Positions in Lebanon and South Africa soon followed.. Holder bank later expanded in North America in the 1950’s. In the late 1970s and early 1980s, Holderbank continued its expansion in Latin America, Asia and Spain for the first time. The company expanded into Eastern Europe and experienced a boom in Spanish construction preceding the 1992 Summer Olympics. By 1986, Holderbank was the world's largest cement manufacturer. In the 1990s, the company consolidated its European holdings as the American market drove growth. Expansion into Eastern Europe and Russia continued (Holcim History 1912-2012). In 2001, the company changed its name from ""Holderbank Financière Glaris"" to Holcim (short for Holderbank ciment) (Holcim History 1912-2012). Holcim expanded by purchasing Aggregate Industries entering into the United Kingdom for the first time. That year, the company also expanded into India by acquiring a stakes in The Associated Cement Companies (ACC) and Ambuja Cement Eastern. In 2008, Holcim became the largest shareholder of China's Huaxin Cement with a 40% stake. In 2009, they acquired Cemex Australia. In 2014, Holcim and Lafarge announced they had agreed to terms on a ""merger of equals"" valued at nearly $50 billion in 2015. The new company LafargeHolcim based in Switzerland has a manufacturing capacity of 427 metric million tons a year."

Jan 1, 2017

By M. Niec

Poland lies at the junction of three geologic provinces: the East European Precambrian platform, the Middle European Paleozoic platform, and the Alpine orogenic belt comprising the Carpathian Mountains. However most of the rocks that contain mineral deposits and many of the recently explored and mined deposits are commonly hidden under thick overburden, sometimes up to over 500 m thick. The discovery of these mineral deposits was due to the combination of geologists talents for inference and the keen interpretation of geophysical data ultimately tested by drilling. Examples of such use of the state-of-the-art geology include the following: 1. Sedimentologic and paleogeographic reconstructions led to the discovery of 8.8 Gt of bituminous coal under 500 m of Jurassic and Cretaceous cover in the Lublin basin, 2. Tectonic and paleogeografic data suggested a potential for discovery of burried Upper Permian copper de-posits on the Foresudetic monocline; subsequent exploration discovered 75 Mt of copper and 0,17 Mt of silver, 3. Geological interpretation of gravity and magnetic da-ta combined with sedimentologic data and regional subsur-face geology resulted in the location of 1.3 Gt of Fe-Ti-V ore in the Precambrian basement of northeastern Poland under -500 m of cover 4. A combination of metallogenic theory and geological interpretation of regional geophysical mapping led to the discovery of Caledonian-Hercynian granites and grano-diorites with accompanying porphyry-type Mo-W-Cu ores below 300 m cover on the northeastern border of the Upper Silesian coal basin 5. Tectonic reconstructions based on gravity and seismic data combined with theory on the origin of native sulfur led to the discovery of 1.0 Gt of native sulfur under cover up to 300 m thick. Five deposits were found at the northern margin of the Carpathian Foredeep. The other deposits found include lignite, polyhalite, lead-zinc ores.

Jan 1, 1996

By H. G. Stephenson

Canada and the United states are both developed countries with economies which are extremely dependant on oil. Canada exports 37% of its production (to the United states) and imports 35% of its consumption (mainly into Eastern Canada), making the country self-sufficient in oil. Canada is attempting to increase its oil production so as to simultaneously reduce its dependence on foreign oil while producing more oil for export. The United states -imports no less than 50% of its total consumption of 17 million barrels/day. Canada's exports to the United states form only 7% of the United States total imports. The United States would clearly prefer to achieve self-sufficiency in oil. Consequently both countries are dependent on foreign oil. The united States is however in the sensitive situation of depending, for its imports, on countries which are susceptible to destabilizing political events. It is the author's hypothesis that recent developments in underground oil recovery from the Athabasca oil Sands of Alberta may well, for both countries, form part of the solution to these problems.

Jan 1, 1991

By J. B. Knaebel

I have been asked to discuss the "Development of the Twin Buttes Mine for Production." This property, which is a large low-grade open pit copper mine about 25 miles south of Tucson, Arizona, was recently brought into production by The Anaconda Company under a long-term lease agreement with the Banner Mining Company. Since the scope of this paper is limited to the subject broadly indicated by its title I will confine discussion of historical, environmental and other general matters to a brief summary sufficient, I hope, to establish a background of those conditions which influenced our approach to the technical and economic problems that faced us at Twin Buttes. The paper deals primarily with our studies and activities related to the solution of these problems and with the resulting engineering and business decisions that were taken - decisions which culminated last September in the initial commercial operation of another major open pit copper producer unique and interesting in several respects.

Jan 1, 1970

By Pawan Bharadwaj, Wim Mulder, Thomas Tscharner, Guy Drijkoningen, Rob Jenneskens

"The Earth’s properties, composition and structure ahead of a tunnel boring machine (TBM) should be mapped for hazard assessment during excavation. We study the use of seismic-exploration techniques for this purpose. We focus on a seismic system for soft soils, where shear waves are better and easier to interpret than compressional waves, as has been shown over the last decade. The system is intended to be deployed on the machine’s cutter head, with a few seismic sources and sufficiently many seismic sensors to tackle spatial variability and noise characteristics. An important property of the newly developed system is its ability to process data with very little human interaction. Images need to be available in near real time, without human interactions slowing down the imaging process. This can be achieved by employing Full Waveform Inversion, which minimizes the difference between modeled and observed data. Because this method may suffer from local minima in the cost function if the data lack low-frequency information, we employ a dedicated seismic source that can generate sufficiently low frequencies for the relevant length scales. With data acquired in a number of field settings that mimic realistic TBM configurations, we show that the designed seismic system can successfully look ahead of the TBM and offers a valuable capability to support decision-making during tunnel excavation. INTRODUCTION While excavating a tunnel with a Tunnel Boring Machine (TBM), the geology and the ground conditions along the planned tunnel trajectory need to be investigated in order to safely and efficiently carry out the underground operations. This entails detecting the occurrence of boulders, foundations, pipes and faults, necessary to prevent hazards and time-consuming delays in the tunnel boring operations. In order to facilitate ground prediction ahead of a TBM, techniques as used in seismic exploration can be deployed. Two components common to seismic-exploration techniques are data acquisition and processing, the latter including inversion. We will discuss each of these for the application to tunnel excavation with TBM, in particular for soft soils."

Jan 1, 2016

By J. D. Vincent

The Henderson mine site is located at Red Mountain on the eastern slope of the Rocky Mountains, approximately 50 miles west of Denver, Colorado. The mill site is on the west slope of the Rockies and mine and mill will be connected by an underground railroad. All designs were for a 30,000 ton per day molybdenite processing plant with provisions for future expansion up to 50,000 ton per day if required. This plan did not just happen, but slowly evolved over the course of about three and one-half years. Many plants cannot afford such a delay, but the Henderson project will take about 10 years from the time it was first discovered until production starts, and these 3 !1 years were well spent in determining the best possible plant site and flowsheet. This paper describes some of the problems and the decisions made in arriving at the final location and flowsheet. The paper does not go into the specific details of how protection of the environment went hand-in-hand with all other project considerations. This particular aspect of the planning has been well-reported on other occasions and considerable information on it is readily available.

Jan 1, 1972

By R. W. Waytulonis

New exhaust control techniques and devices may be necessary to meet future diesel particulate matter emission standards in underground coal mines. This paper reviews conventional work practices and devices used to control diesel exhaust emissions, and new techniques being tested by the Bureau of Mines. Discussions will center on important work practices and on the function and efficiency of exhaust after-treatment devices. An industry/government cooperative research project to develop and test an exhaust after-treatment system for part 36 equipment is also discussed.

Jan 1, 1990

By A. W. Khair

This paper deals with the causes and mechanisms of pillar failure in a southern West Virginia coal mine. The conclusions are based on in-mine observations and analysis of mining methods, eyewitness account of the sequence of events, topographic and geologic conditions, and mechanical properties of mine roof, coal, and floor. The study indicated that massive pillar failure was caused by the collapse of the mine roof. The collapse of the mine roof was due to the combined effects of high lateral compressive stress and high extraction ratio causing excessive bending of the roof beyond its limit. It was assumed that the higher lateral compressive stress under such a shallow cover was probably due to the drastic change in the structural geology of the area and possible residual stresses. Eased on the analytical study it was concluded that the sudden release of elastic energy (shock) due to the rupture of the roof caused the squeezing of approximately eighty mine pillars.

Jan 1, 1983

By F. T. Paleari

Radial gas holdup profiles have been measured in a 50x400 cm flotation column using a multi-cell conductivity probe. Three different bubble generation systems were examined: up to eight vertical filter cloth spargers, three horizontal filter cloth spargers, and three (horizontal) Cominco-type spargers. The variables tested were: number of spargers, symmetry of their arrangement, and height above spargers. Batch water with up to 20ppm frother concentration was used. The general observation is that the profiles tend to be uniform (i.e. flat) with some exhibiting a slight wavy shape. The vertical sparger arrangement proved the most difficult to achieve profile symmetry. The horizontal spargers gave uniform profiles at right angle to their length but a decreasing gas holdup along their length; the Cominco-type spargers gave slightly less scatter in the data. Switching off selected spargers (to simulate malfunction) did not produce strong asymmetry in the profiles.

Jan 1, 1993

By M. S. Klima

Coal gasification solid residue (slag) contains unconverted carbon (char), which is considered an impurity for utilization applications of slag. Under this study, table concentration was used to process approximately 24,000 pounds of a nominal-3.4 mm gasifier slag (-85% ash) to separate high (-100%) ash slag from low (-50%) ash char. The results indicated a nearly ideal separation of the slag from the char for sizes coarser than about 1 mm. An overall slag yield of 71 % was obtained. The slag was sufficiently clean to be used as feed material for the production of expanded lightweight aggregate. The recovered char had an ash content of about 47% and was a nominal -1mm in size.

Jan 1, 1997

By Cuthbert Musingwini, Adeodatus S. Nhleko, Mahlomola I. Mabala

Optimization of a three-dimensional (3D) underground stope layout is complex given the number of variables and constraints to consider, such as the stope size. Determination of the appropriate stope size in stope layout optimization problems is a complex process that must consider several factors including placement of infrastructure and development, production scheduling, and equipment selection. An inappropriate stope layout can result in unrealistic expectations for a production schedule, consequently negatively affecting the derived economic value. Therefore, this paper used a dual interchange algorithm (DIA) to evaluate the effect of stope size on the stope layout economic value (SLEV) for a synthetic Platreef mineral deposit planned for extraction using sublevel open-stoping. The results showed that generally as the stope size increases, the SLEV decreases. This aligns with practical mining because larger stope sizes have a higher chance of incurring more dilution which reduces economic value, while smaller stope sizes enable more flexible extraction where unprofitable blocks can be left unmined as waste, thus increasing the derived SLEV.

Jun 25, 2023

By Keith G. Wallace, K. M. (Chris) Chmura, Kirk H. McDaniel

The Waste Isolation Pilot Plant (WIPP) performed a feasibility analysis for the purpose of either modifying, supplementing, or replacing its two main mine fans. The WIPP, located near Carlsbad, New Mexico, is a U.S. Department of Energy (DOE) fa¬cility designed to demonstrate the permanent, safe disposal of U.S. defense-generated transuranic waste in a deep bedded salt deposit. Since the centrifugal fans were installed in 1988, multiple op¬erational and performance concerns have been identified. A com¬prehensive engineering study was conducted in 1995 to: 1) Qualify and quantify operational concerns, 2) Evaluate possible alternatives, and 3) Recommend an optimum solution. Multiple system modification and/or replacement scenarios were evaluated with associated cost estimates developed. The study considered replacement with either centrifugal or axial fans. Multiple fan duties are required at the WIPP. Therefore, Variable Frequency Drives and Inlet Vane Controls (IVC) were investigated for centrifugal fans. In-flight adjustable blades were investigated for axial fans. The study indicated that replacing the existing system with two double-width, double-inlet centrifugal fans equipped with IVCs was the best choice. This alternative provided the most desirable combination of: 1) ensuring the required operational readiness, and 2) improving system performance. The WIPP is currently planning to replace the first fan in 1997.

Jan 1, 1997

By J. Duran

Mining at Phoenix is currently done by surface operation in the Fortitude and Bonanza Pits, at a combined rate of approximately 110,000 tons per day. A portion of the ore bodies targeted by these pits was mined previously by underground mining methods, dating back to the mid to late 1800?s. Most of the underground workings (voids) are located in the west central area of the Bonanza Pit. The surface operation requires excavation through voids, and there is a risk of pit floor subsidence that has to be addressed. This paper presents a review of the risk mitigation measures that were implemented to reduce risks to people and equipment working in the area.

Feb 23, 2014

By M. Pantazidou

Motivated by recent EU legislation already entered into force or in preparation, this article aims at offering glimpses of the future landscape in the area of subsurface protection against contamination from point sources. Towards this end, it discusses the most salient parts of legislation for the protection of water resources. It then presents results from the wide consultation rounds organized by the European Commission in order to both receive input and help make all opinions heard on the issue of soil protection. Finally, it introduces key provisions of the recent legislation on environmental liability. From the above pieces of legislation, this paper highlights the elements that concern specifically the protection of the subsurface against spills of hazardous wastes from point sources and the requirements for subsurface restoration.

Jan 1, 2005

By M. Manrique

Various pyrometallurgical methods for treating Ilmenite and Zircon concentrates are reviewed. Laboratory experiments, using a thermal plasma reactor, have been performed to evaluate: the conversion of ilmenite to TiC or TiC-Fe and the conversion of zircon to ZrC or ZrC-SiC. Results are examined and possible processing routes are identified.

Jan 1, 1996

By Richard A. Bideaux

During 1977 and 1978, a comprehensive study was made of the drill-hole data obtained by Urangesellschaft, USA, from their Juniper Ridge, WY, uranium deposits. This included uranium grade data acquisition, application of a variety of mineral deposit modeling techniques, and estimates of minable reserves, which pointed towards a possible production decision.

Jan 1, 1979