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By Brian Flintoff

"When I was first asked to prepare this paper and presentation in late June, I thought it might be fun to ""step back and paint the bigger picture."" Having attempted to do this, fun is not the first descriptor that now comes to mind, and speaking dyslexically, I've had 'nuf.'Unlike Nostradamus, or even Orwell, I've discovered that I'm ""clairvoyantly challenged"" and not even the psychic hot-line was of much help, at least with respect to process control! I am somewhat comfortable speculating on evolutionary change, but the radical developments that will arise from revolutionary changes are well beyond my mortal capabilities. Even with evolutionary change, I'm reminded of the lessons of time series analysis which show the prediction error to grow exponentially as the horizon moves into the future. As Macluhan is reported to have said: ""Predicting the future based on the past is a little like driving your car while looking in the rearview mirror!""Having honestly presented my qualifications, allow me to try to look at process control and to offer some conjecture on where we're probably headed. In the end, it is said that: ""The plant of the future will have only two employees, a man and a dog. The dog will be there to keep the man from touching the equipment.1""IntroductionA little less than a decade ago Andy Mular and I co-edited a monograph entitled ""A Practical Guide to Process Control in the Minerals Industry."" The work was commissioned by the senior management of a consortium of Canadian mining companies, since it was widely perceived that control was an area of great economic potential, but one that had not been effectively tapped. The concern was that if the industry could not soon deliver on the ""potential"", the term may well have appeared in the epitaph of what was, to these men, a very attractive investment opportunity. I think it is fair to say that over the past few years process control has clearly established itself as an essential technology in plant operation and optimization. That isn't to say that we get it all-right, all-the-time, but, the circumstances are much different than they were. In the eyes of many, process control has attained the distinction of being considered a mature technology, even though there are still countless avenues for exploration."

Jan 1, 1998

By Sarah Holtz Wilson, Kenneth Rossi, Carl R. Handford, David F. Tsztoo

The East Bay Municipal Utility District’s Claremont Tunnel is an 18,000-foot long water tunnel that crosses the Hayward Fault zone near Oakland, California. It was originally completed in 1929. This project involved the construction of a bypass tunnel through the fault zone, including an enlarged vault section designed to accommodate up to 8.5 feet of horizontal offset. Ground conditions encountered included sheared and crushed serpentinite and clayey fault gouge, and presented specific challenges for construction. A special excavation and support sequence used concrete-backfilled side drifts as foundations for the vault steel sets. It also allowed for a 20-foot-wide top heading and bench excavation in soft and squeezing ground conditions.

Jan 1, 2007

By A. Mahmoudkhani

Primary cementing is the process of placing cement in the annulus between the casing and the formations exposed to the wellbore. Portland cement was first used in 1903 in the Lopoc Field in California for well cementing. Since then, the major objective of primary cementing has always been to provide zonal isolation in oil, gas and water wells, i.e. to exclude fluid(s) in one zone from another zone in the well. To achieve this objective a hydraulic seal must be created between the casing and cement and between the cement and the formations, while at the same time preventing fluid channels in the cement sheath. This requirement makes primary cementing the most important operation performed on a well. Without complete isolation in the wellbore, the well may never reach its full producing potential. The industry knowledge on cements relies heavily on empirical data, but the chemistry, physics and structure of cement are not fully understood yet. The strength of concrete can be increased essentially by reducing its porosity through optimizing the size distribution of its components and filling the residual porosity of the hydrated cement phase with inorganic fillers. This approach has successfully utilized in different ways and several technologies for placing high performance oil and gas well cements have been developed over the last few decades. There are reasons to believe that the next source of improvement will lie in the fine-tuning of the hydrates themselves and of the different parameters that drive short (ionic?covalent bonding) and long (ionic correlation) interactions.

Jan 1, 2012

By Robert Hopler

In issuing this pamphlet on stump and boulder blasting for the use of farmers, we wish to call attention to the fact that Du Pont High Explosives have been used with universal satisfaction for many years under diverse conditions, and have never failed to give satisfaction in mining, quarrying, roadmaking, blasting stumps and boulders, or for any other work where regard to economy and safety in use is the object.

Jan 1, 2008

By Jack Curran

KANSAS CITY, MO - Performing one of the most impressive urban building-implosion projects in recent memory, Tulsa, Oklahoma-based Dykon Explosive Demolition Corp. and Omaha, Nebraska-based Anderson Excavating recently felled the landmark Columbia Bank Building in downtown Kansas City, Missouri, USA. Although every structural blasting project presents special challenges, this undertaking was most notable for its unusually unique structural design, tight clearances, and high risk to adjacent structures.

Jan 1, 2003

A new system for granting access to mineral rights is proposed in the recently released White Paper, ?A Minerals and Mining Policy for South Africa?. Official policy states that ?Government?s long-term objective is for all mineral rights to vest in the State for the benefit of and on behalf of all the people of South Africa?. In order to achieve this objective, government is presently investigating the feasibility of imposing a financial or tax-related disincentive to holding mineral rights. The paper aims to present the pros and cons and to examine the alternatives which will cause minimal disruption to the minerals industry in the period during which mineral rights are transferred to the State. South Africa is a country whose economic and political history is embedded in the development of its mineral resources and has inherited a system which cannot simply be wished away. Hasty or radical decisions will compound the problem, rather than provide a lasting and widely acceptable solution. Mineral rights ownership and its impact on access to mineral deposits are discussed. Taxation as a possible economic disincentive is also evaluated. Finally, the value of mineral resource related information as a prerequisite to mineral policy decisions and as an alternative to mineral rights taxation is emphasized.

Jan 1, 1999

By J. von Schéele

OXYFINESTM is an oxyfuel-based concept for in-plant recycling. It enables the possibility of fines, dust, sludge (without any drying step) and other by-products generated by the steel- and metal-producing industries to be recycled directly back into existing processes or a separate on-site unit. The results from a full-scale installation (20 000 t/a) and pilot-scale trials with dry and wet materials in the steel and ferroalloy industries are presented. The latter include materials arising from ferrosilicon, ferrochrome and silicon manganese production. The concept not only provides a solution to the problems associated with dust and sludge generated in metal production, it also turns these materials into a low-cost raw material which is useful for the same production process, thus replacing some of the raw material input. If required, it could also be used, possibly as an intermediate solution, to convert the dust or sludge into an inert material with a suitable shape. Under some conditions, a directly saleable product could also be obtained. The paper reviews this technology, its status and benefits as wells as its possibilities with regard to application in ferroalloy production. Keywords: recycling, fines, dust, sludge, ferroalloys

Jan 1, 2004

By Stanley R. Riggs

The rocks exposed in the phosphate district are of Neogene age and consist of clayey quartz and phosphorite sands overlying phosphatic dolomite. The Bone Valley Formation is redefined as a marine phosphorite containing primary phosphorite and abundant terrigenous sediments. It contains a Middle Miocene vertebrate and invertebrate fauna and conformably overlies the Hawthorn Formation containing similar invertebrate fauna. A new, unnamed formation, with Pliocene and Pleistocene fauna and containing reworked phosphorite, overlies the Bone Valley disconformably. Its phosphorite is derived from the subjacent Bone Valley by post-Middle Miocene erosion and deposition in stream channels and marginal marine environments. The Bone Valley contains two main types of primary marine phosphorite. Orthocbemical phosphorite, a direct precipitate of microcrystalline phosphorite (microsphorite), occurs as a cement or binder in thin beds. Allochemical phosphorite consists of clastic phosphorite particles that were originally formed as microsphorite on another part of the shelf. Microsphorite was deposited in a very shallow open marine environment which had an abnormally high phosphorous content caused by upwelling currents. The mechanism of deposition is still in doubt, but organisms probably were a major factor. Soon after deposition, microsphorite was indurated, periodically torn up, and the resulting fragments transported and deposited elsewhere on the shelf. These processes account for a great portion of the clastic phosphorite in the Miocene deposits of Florida. The primary fossil skeletal material is of minor importance.

Jan 1, 1965

Alluvial gold was found in the Terawhiti area, West of Wellington, in the 1850s. This led to the discovery of reef gold. Periods of minor 'gold fever', company flotations, and mining activity occured between 1869 - 1973, 1881 - 1986, and in the late 1880s, with one final company active in 1911 - 1914. 1n the early 1980s, further field work was carried out. No viable mining operations resulted from any of this activity.

Jan 1, 1993

By Dyson N. F

Mixed cobalt-nickel sulphides precipitated from ammoniacal process liquors derived from nickel sulphide concentrates, mattes, and reduced nickeliferous laterites have been characterized.The mixed sulphides are prone to oxidation on standing and are rapidly leached under relatively mild conditions. The kinetics of the leaching reactions are controlled principally by temperature and oxygen partial pressure. Although the samples have different CO:Ni ratios and have undergone varying degrees of oxidation, there is little difference in their leaching behaviour. The results suggest that a single plant would be able to process mixed sulphides of varying composition. Any copper and zinc present in the mixed sulphides as impurities also go into solution and must be removed prior to recovery of the cobalt and nickel in metallic form.

Jan 1, 1981

Technologies are receiving a lot of 'press' - and rightly so; as they are seen as the means for achieving quantum leaps in productivity and cost reductions. A point of concern for Caterpillar is that we do not believe there is enough understanding of the infrastructure needed to support some of the future technologies, as well there is not enough utilisation of the current systems.

Jan 1, 1997

By P. J. Rider

Diamond Value Management?s objective is to achieve $/ton revenue improvement across De Beers group mines. The respective %improvement contributions are measured against targets set by each of the operations. Degree of target achievement is measured via a maturity model at each operation. DVM comprises seven elements. It spans several value chain facets and various collaborative projects are conducted under its umbrella. New technologies in De Beers are also evaluated from a DVM perspective.

Jan 1, 2003

By A. W. Breed

The bioleaching of arsenopyrite, the oxidation of arsenate and the precipitation of ferric arsenate are competing reactions, hence their rates depend on the relative concentrations of the respective species, and the activity of the bacterial culture. Bacterial arsenic resistance may be attributed to the Pst+Pit-mutation and an energy dependent efflux pump. Pst+Pit-mutations result in a reduced uptake of arsenate. This enables the bacteria to survive in solutions in which the arsenate concentration is significantly higher than the arsenite concentration. However, the excretion of arsenate requires energy. Therefore, in the absence of an energy source or during periods of reduced bacterial activity, the inhibitory effect of arsenate may manifest at concentrations to which the culture has been adapted. The chemical ferric leaching rate of pyrite and arsenopyrite decrease with a decrease in the solution redox and may be described using a modified Butler-Volmer equation. The bacterial ferrous-iron oxidation kinetics of L. ferrooxidans also depend on the redox potential, and can be described using a Michaelis-Mententype model modified to account for both temperature and pH. A model developed using the independently determined ferric leaching, and ferrous-iron oxidizing kinetics, has been shown to compare well with the experimental data for the continuous bioleaching of pyrite. Keywords: Leptospirillum ferrooxidans, arsenopyrite, bioleaching, sulphide minerals ferrous-iron oxidation kinetics, ferric leaching kinetics, redox potential

Jan 1, 2000

By Maurizio Siepi

The realisation of most of the civil engineering works is subordinate to the execution of consolidation works, in order to improve the soil physical-mechanics characteristics. The works classifiable with the term "Soil Improvement" can be realised using several technologies, among which the Deep Mixing Method is distinguished for his remarkable flexibility and productivity characteristics. The Deep Mixing Method is a process whereby a rotary drilling machine mechanically drills a constant diameter hole while cement slurry is injected into the soil at high pressure. The process combines state of the art construction techniques merging mechanical and hydraulic mixing energies at the tool bit. The result is a soil-cement column of engineered strength, consistency and dimension. Whereby the soil cement column formation process is controlled by a computerised device, the result is a speedy installation, thorough mixing, and a high degree of control, repeatability and documentation.

Jan 1, 2002

By D. Kolymbas

A simple formula is introduced which allows the evaluation of dynamic pile tests. The following case is considered: The pile top is dynamically loaded by an impact. The velocity v of the pile top is recorded over the time. Let v1 and v2 be the first and the second maximum of this curve. Then, the pile bearing capacity (resulting from ideally plastic resistance at the pile wall and at the tip) can be set approximately equal to Z(v1- ½ v2), where Z is the impedance of the pile cross section. Due to the assumption of ideal plastic resistances, radiation damping needs not be taken into account. Material damping may be important in rate sensitive soils (such as clay, even if it is highly overconsolidated). A simple correction procedure for material damping is proposed.

Jan 1, 1989

By Italo Onederra, Jason Furtney, Ewan Sellers

The detonation reactions occurring during rock blasting result in high pressure gas phase products from the condensed explosives typically used in mining applications. After detonation and the initial fracturing, the work done by the expansion of this gas contributes to burden movement and further rock fracturing. Before all of the energy in the reaction product can do useful work on the rock, some of this energy is lost to crushing and possibly to gas venting to the atmosphere. Borehole gas pressure decreases by three principle mechanisms: (i) expansion of the borehole cavity, (ii) flow into the fracture network, and (iii) flow through the stemming. To simplify the problem and to get a better understanding of the interaction of these mechanisms, a simple model for each of these mechanisms is developed. A comparison is made of the time-scales and the influence on burden movement for each. A comparison of gas flow behavior is made between typical ANFO and emulsion products.

Jan 1, 2012

By Walter C. Woodmansee

The only reported mineral production in 1977 was small output of alluvial gold, valued at an estimated $54,320.2 In addition, marine shells are gathered for use in lime manufacture, although output was not reported. Proposed development of a bauxite mine and smelter, involving Rennell and Vaghena Islands, was deferred in June. Conzinc Riotinto of Australia Ltd. (CRA), in partnership with Mitsui Mining & Smelting Co. Ltd., and the Solomon Government, with- drew from the project, and Mitsui, which conducted a feasibility study and metallurgical testing of the bauxite, decided to defer further work because of slack demand for aluminum in Japan and difficulties in arranging financing. The Mitsui feasibility studies reportedly indicated that the project could be viable despite technical difficulties and relatively high initial investment costs. The project was to produce 1.5 million tons of bauxite and 600,000 tons of alumina per year from reserves totaling 60 million tans at 45% to 50% A1203.

Jan 1, 1981

By Claudia Monreal L., Dafne Herreros

"The Geological Modeling is the undisputed point of split of any type of mining method, the effect that the vision and experience of the geologists is propagated trough the development of the project and is an important part of the final success. The collection of information is taken in stages. In earlier stages uses the greater part of the budget and the strategy to store and manage this data collection, as its performing will define the destiny of the deposit and of the business. With this background the geology and its modeling receive great attention from the industry and care providers being a fertile field in research and innovation. "

Sep 1, 2017

By A. More, J. M. Míguez, J. Bullón

In 2000 Ferroatlantica started a project with the aim to develop a new casting machine for silicon and other ferroalloys. Until now, it has been cast more than 25.000 tons of silicon for the chemical and metallurgical market. This system has improved the process yield, productivity and product quality which place?s Ferroatlantica at the top of technology development in this field. After the first presentation of the Ferroatlantica?s casting machine at Infacon X, we would like to show the improvements in the control which have permitted us to increase the lifetime of the copper and to obtain, at the end of the machine, the right product size for the customer avoiding the current necessity of crushing and sizing the lumpy metal. Furthermore, we have improved the system in relation to the obtaining of smaller granulometries at the end of casting machine. Not only is this kind of machine cost competitive for special silicon applications but also for other normal ferroalloys with different specifications of size and thickness.

Jan 1, 2007

By Stephen C. Tadolini, Thomas M. Barczak, Peter (Yunqing) Zhang

A cooperative study was conducted with Emerald Coal Resources, L.P., an affiliate of Foundation Coal Corporation, and the National Institute for Occupational Safety and Health (NIOSH) to evaluate the effectiveness of (partially) pre-driven longwall recovery rooms supported with pumpable roof supports. This paper evaluates the load transfer mechanics associated with the advancement of the longwall face into the pre-driven recovery room and the widening of the room to recover the longwall shields. The results show that the yielding of the panel fender produced uncontrollable convergence that caused yielding of the shields and stiff pumpable roof supports when the face was approximately 10 ft from the recovery room. The shields continued to yield until the face advanced into the recovery room. Convergence in the pre-driven recovery room typically reached 6-8 in once the pumpable supports yielded and shed load through a declining residual load capacity prior to being cut out by the longwall shearer. Roof deformations occurred beyond the 32-ft horizon with total deformation ranging from 2 to 4 in, indicating that standing support was necessary to help control the span as the longwall face advanced into the pre-driven recovery room. Stability improved as the pumpable supports were cut out, thereby reducing the span between the shields and the outby pillars. In the end, the shields were successfully recovered under stable ground conditions. However, a disconcerting discovery was the load shedding of the outby pillars as the recovery room was mined into. It is postulated that this may be due to the progression of the rear “abutment” moving toward the recovery room as the panel fender and standing support in the recovery room yield and shed load. This behavior was not expected with a relatively narrow room that is fully supported with standing support. If this mechanism is indeed occurring, the width of the room and performance of the standing support becomes even more critical. Premature failure of the support can lead to excessive convergence on the shield line that cannot be controlled even with modern shields, resulting in roof instabilities that can lead to catastrophic results.