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By Fernando H. Muge

The first application of dynamic pro¬gramming to the problem of grade control and scheduling was by Muge et al (1979) and Ribeiro (1982) who applied it to the simple, two-dimensional case of longitudinal open stoping using two sublevels. In this paper the formulation of the problem is extended to cover the general case applied to a cut-and-fill mining method. The criterion for optimization is the total deviation of the average, grades of mining blocks from the overall average panel grade (or the average grade of a set of mining panels or the mine processing working point). This means to schedule the operation by removing a certain number of mining blocks at a time, subject to the geometric (mining) constraints, and such that the total deviation of average block grades from overall average grade is minimum. The method can be applied to complex orebodies with several ore characteristics and the deviation of each one of these characteristics can be further constrained by specifying maximum values. The method can also be generalised in order to take into account any necessary geometric constraints used to define the mining method. In this paper a case study is presented concerning the mine planning of a complex sulphide orebody located in the South of Portugal. As input for the definition of the mining sequence, a geostatistical numerical model of the orebody was built based on a previous ore typology. The short term planning is used to assess specific mining sequences and the production scheduling is performed on the basis of an objective function (e.g. minimization of grade fluctuation).

Jan 1, 1989

By R. J. Enkin

Modern mineral exploration depends on multidisciplinary 3-dimensional integration of geological and geophysical data. Identification of the geological sources of geophysical anomalies requires knowledge of the physical properties fingerprint of rock types, formations and their alteration products. Understanding how and why rock physical properties vary within the Earth's subsurface ensures that appropriate geophysical exploration methods can be chosen, and allows for more efficient and effective surveys to be designed. Physical properties knowledge is integral to geophysical modeling - measured data or values estimated based on geological understanding are used to produce realistic forward calculations and to constrain inversion models. Mira Geoscience and the Geological Survey of Canada, in collaboration with industry and academia, are building a Rock Properties Database System (rpds.mirageoscience.com). It compiles the most valuable physical properties for mineral exploration (density, porosity, magnetic susceptibility and remanence, electrical resistivity and chargeability) linked with location and lithological metadata. A critical knowledge gap, addressed in this study, concerns the dependence of physical properties on alteration and mineralization processes. We report on the results of a collaborative University of British Columbia - Geoscience British Columbia project, ?Integrated Geological & Geophysical Porphyry Models: Adding Value to Geoscience BC Geophysical Data?. As part of the QUEST and QUEST-West geophysical initiatives, Geoscience BC focused detailed geophysical surveys on a suite of six known porphyry deposits: Mount Milligan, Endako, Huckleberry, Bell, Granisle, and Morrison. Physical properties for a set of 269 samples of characteristic host rocks and their altered equivalents were measured. The causes of physical properties variations were investigated through their correlations with ore and alteration mineralogy determined from thin-section observations and X-ray diffraction analyses. Physical properties of variably altered host-rocks and intrusive rocks vary significantly between different BC porphyry deposits. No specific unifying geophysical model exists that can be uniformly applied during exploration. Knowledge of local background geology and local physical properties variations is necessary as host-rocks and intrusive rock compositions vary depending on magmatic affinities, and alteration styles will vary reflecting host-rock compositions, crustal depth and influence of meteoric water. A district-scale exploration strategy requires location of intrusive bodies, which are commonly magnetic, resistive and low in density. Correlations should not be expected between density and magnetic susceptibility, because alteration may lead to magnetite destruction or to secondary magnetite development. Deposit-scale ground geophysics might image potassic alteration zones that can be magnetic in both alkalic and calcalkalic systems. Low magnetic susceptibilities, resistivities and densities might aid in locating the typically more porous phyllic and argillic zones. All geophysical data must be interpreted with background knowledge of local rock types and in light of the expected deposit model and associated magmatic and hydrothermal processes. The most effective means to building physical properties knowledge prior to geophysical investigation remains collecting rock physical properties measurements. The cost of rock properties data collection is low, relative to the overall costs of running a mineral exploration program, and can provide an important framework for design of geophysical surveys, survey method selection, geophysical modelling, and data interpretation.

Aug 1, 2013

By J Joy, A Bye, G V. Kizil

This paper presents an application of the newly developed risk-cost-benefit (RCB) framework to support risk management decisions for the selection of wall monitoring technologies at an open cut mine site. The RCB framework quantitatively assessed the risk of unstable slope-induced wall failure and its impact on both loss of life and coal recovery. The RCB framework was utilised in the selection of an optimum group of risk-controls to effectively manage the risk of wall failure to ensure safety and optimal production occurred. The RCB framework incorporates mathematical modules that integrated RCB calculations and risk-control effectiveness assessments to determine the risk reduction and financial impact of the examined safety initiatives.This paper provides an overview of the five-staged RCB framework, incorporating the RCB decision support tools, RCBGEN (Risk-Cost-Benefit Generator) and RCEMETHOD (Risk-Control Effectiveness Method), and demonstrates its application to slope stability risk management at the case study site. The RCB charts are designed to display a balance between risk, cost and benefit for easy interpretation by decision makers to support the objective selection of an optimum suite of risk-controls. The RCB analysis revealed that a combination of ævisual inspections, automatic extensometers and radarÆ for fast- and slow-wall failures with structure were sufficient to reduce the probability of loss of life (PLoL) to the æModerateÆ zone as defined by the Australian Geomechanics Society (AGS, 2007) for the case study site. The new framework presented in this paper provides a method to effectively determine the suitability of risk-controls and supports industry efforts to reduce risk to as low as reasonably practicable (ALARP).CITATION:Kizil, G V, Bye, A and Joy, J, 2012. Risk-cost-benefit analysis of early warning technologies impact for wall failure risk management in surface mines, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 55-64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By Andrew P. Schissler

The Citronen Zinc-Lead Project is one of the world?s largest undeveloped zinc-lead resources, containing more than 13 billion pounds of zinc and lead metal. The project is located in northern Greenland, a self-governed region of the Kingdom of Denmark (Figure 1). Citronen is the northern-most mine in the world, operating at a latitude of 83o 3? N. In excess of 67,000 meters of diamond drilling have been completed to delineate the resource. As of January 2012, the measured, indicated, and inferred reserves for the Citronen project totaled 70.8 million tonnes, consisting of 5.7% zinc + lead (3.5% zinc cut-off) (Ironbark, 2012). For the underground mine plan, room-and-pillar and long holestoping mining methods were selected. The beneficial application of structural fill was considered for increased recovery, efficient tailings disposal, and ground control. Three types of fill were compared - paste fill, cemented rock fill, and iced tailings. An environmental and economic feasibility study concluded that iced tailings was the preferred alternative provided it met the ground control requirements. The purpose of this paper is to explain the investigatory steps that led to the possibility for the use of iced tailings as structural fi

Jan 1, 2012

By F. Bello, R. Yanez, M. Pinto, T. Errazuriz

"Throughout its operation, Minera Esperanza (ME) will deposit one of the largest tonnages rates of high density tailings in the world with a solids concentration of close to 67% by weight. The tailings presently being deposited have a solids concentration of approximately 62% - 64%, and so cannot be used to directly characterize the flow and deposition characteristics of the higher concentration tailings. To increase the knowledge of the behaviour of their tailings, ME, with the support of Golder Associates, developed a large scale tailings deposition test with a capacity of 30,000 tonnes per day (1,200 m3/h). The test was carried out by depositing tailings into two large cells or paddocks in five stages. Multiple spigots were used to allow different flows to be deposited. At each stage, topographical surveys of the natural terrain and the geometry of the deposited tailings, as well as continuous flow measurement and periodical rheological characterization of the discharged tailings were conducted to create a data set against which beach slope models could be calibrated and then used to predict performance of the higher concentration tailings under different deposition scenarios. This study adopted the beach slope prediction model proposed by A.L. Li (Li, 2011). The model was successfully adjusted to the observations made during this large scale field test by applying the values measured in-situ. This paper presents the application of the model, the results obtained, the findings, and the analysis of possible future scenarios. The model was applied, using the discharge flow rate, the geometrical characteristics of the discharge area, and the rheology with its variation along the beach to estimate the development of the beach formation and the steady state of the beach slopes. Through the use of dimensionless variables, the model was applied to higher solids concentration scenarios, obtaining results that would allow beach slope estimation at different deposition stages in multiple scenarios of varying parameters such as flow, rheology and geometry of discharge area."

Jan 1, 2014

By Greaves M. C, Amos M. D

A study was made of the instrumentation and technique of atomic absorption spectroscopy developed by Walsh of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia.The method was evaluated for the determination of silver in lead sulphide concentrate. The precision of the procedure developed is equal to that of the uncorrected fire assay method and the accuracy is greater.Brief mention is made of the use of this technique for the determination of silver and other elements in ores and concentrator products.

Jan 1, 1994

By S. Malopheyev, I. Vysotskiy, R. Kaibyshev, S. Mironov

"In this work, the effect of pre-strain rolling on the annealing behavior of friction-stir welded 6061-T6 aluminum alloy was studied. To this end, the as-welded material was rolled to 10 or 20 pct. of thickness reduction prior to the standard post-weld T6 heat treatment. Three rolling directions were the 3-mm thick sheet were considered: along the welding direction, perpendicular to the welding direction, and at the angle of 45° to the welding direction. At relatively low pre-strains (10 pct.), the annealing behavior was found to be very sensitive to the rolling path, and rolling along the welding direction was most effective in suppressing abnormal grain growth. On the other hand, increasing the pre-strains to 20 pct. of thickness reduction inhibited abnormal grain growth irrespective of the rolling path.INTRODUCTION Heat-treatable wrought Al-Mg-Si alloys are widely used due to attractive combination of strength, ductility, excellent corrosion resistance and low cost (Polmear, 2006). To provide the optimal balance of mechanical properties, these materials are typically commercially available in appropriately work- and precipitation-hardened conditions (Polmear, 2006). During conventional fusion welding, however, the prior strengthening effect is totally lost due to elimination of the work hardened structure and dissolution of the strengthening precipitations. An innovative friction-stir welding (FSW) technology may partially overcome this problem. Due to the solid-state character of this process, which involves very large strains, the welded material is characterized by fine-grained microstructure with moderate-to-high dislocation density, and thus the prior work hardening effect may be preserved or even enhanced (Threadgill et al., 2009; Mishra & Ma, 2005). However, heat input associated with FSW inevitably leads to dissolution and/or coarsening of strengthening precipitates, thus giving rise to the undesirable material softening. In an attempt to restore the strength of the friction-stir welded material, the standard T6 post-weld heat treatment has been applied, but this approach was found to lead to abnormal grain growth (Malopheyev et al., 2016; Mironov, 2013, Mironov et al., 2015)."

Jan 1, 2018

By M. A. Schellhardt

The Bureau of Mines has made periodic back-pressure tests on numerous gas wells in the Texas Panhandle field during the past several years to study the delivery capacities of the wells under different pressure and operating conditions and to determine the relationships between pressures and rates of delivery from gas wells.4/ However, information regarding the intake capacities of gas-well systems is meager, end in projects involving the flow of gas into porous-rock reservoirs it has been necessary to determine intake capacities of gas wells by trial. Accordingly the fundamental intake characteristics of natural-gas yells have been studied to develop a method for determining intake capacities under different wellhead pressures from data descriptive of the "output" or producing characteristic of the wells.

Jan 1, 1936

By Trevor I. Addenbrooke

Stress reducing piles were used for the first time at the Queen Elizabeth II Conference Centre near the Palace of Westminster in London, UK. The inclusion of these piles directly beneath heavily loaded columns was to reduce the high anticipated bending stress in the foundation raft, and to eliminate local yield of the London Clay beneath the column locations. Load cells were placed in one of the stress reducing piles during construction. The data showed that the pile carried about 30% of the column load. This can be contrasted with conventional piled raft design where the pile carries upwards of 80% of the column load. The build up of load on the pile and pile displacement have been accurately reproduced using coupled finite element analysis. These numerical results demonstrate the value of geometrically simple axially symmetric analyses for modelling a pile-enhanced raft. On site, excavation preceded construction of the raft and subsequent pile loading. Failure to model this construction sequence caused the shear strength to mobilize at the base of the pile first, during loading, whereas following the construction sequence caused the shear strength to mobilize at the top of the pile first.

Jan 1, 2002

By Rolf Schillinger

Blasting activities on the surface or underground necessarily involve the most sensitive aspect of environment remediation, human response or annoyance. Such effects are unavoidably characteristic of those activities. For this reason, blasting activities are governed by law and official regulations under surveillance of authorities, where companies and explosives engineers have to proceed within proper limits. Subject of the paper is a practical way of handling some necessary vibration standards being focused on blasting activities. The paper is based on the German Standard DIN 4150, Part 1 - 3, “Vibration in buildings”, Part 1: “Prediction of vibration parameters”, June 2001, Part 2: “Effects on persons in buildings”, June 1999 and Part 3: “Effects on structures”, February 1999.

Jan 1, 2006

A thermomechanistic model was developed for the thermal decomposition of the enargite contained in a copper concentrate at 650° to 750°C in a fluidized bed with an inert atmosphere. At the particle level, the model permits one to predict the thermal profile inside the reacting enargite particles, as well as their thermal cycle. At the macroscopic level, a population-based model coupled to the bubbling-bed fluidized bed model allows one to predict the fractional conversion (dearsenification) of an enargite-bearing copper concentrate.

Jan 1, 2002

By Lénaick Menot, Anne-Sophie Alix, Charline Guérin, Sébastien Ybert, Ewan Pelleter, Florian Besson

Ifremer, on behalf of the French government, holds an Exploration Contract with the ISA for polymetallic nodules in the CCFZ. As part of its exploration activities, the NODULE (2015) cruise was conducted to acquire a 50 m resolution bathymetric coverage of the eastern sectors of the Contract. In 2017, Ifremer initiated an update of the Contract’s mineral resource estimate. Metal grades and nodule abundance were modelled using ordinary kriging. The inferred mineral resource is 436 Mt (wet) of polymetallic nodules at an average abundance of 10.7 kg/m² with a cut-off grade of 7 kg/m². Based on the geological data, seamounts, sedimentary basins and steep slopes contain no nodules. Technical studies of most of the contractors have determined that nodule collectors could not maneuver on slopes above 5 to 10°. Thus, Ifremer has selected a quite conservative slope threshold of 7 % (about 4°) and a backscatter threshold of -29.5 dB to delineate nodule-free areas. This has a significant impact on the resource estimate, as about 54 % of the eastern Contract areas are excluded. Near-seafloor high-resolution mapping and photographic transects, associated with finer-spaced box-core sampling could constitute a next step to better constrain the mineable areas and to get a higher level of confidence in the resource estimation.

Jan 1, 2018

By Francisco Cadena

The construction of Norris Dam, built by the Tennessee Valley Authority on the Clinch River, a tributary of the Tennessee River, involved the production of coarse and fine aggregate for approximately 1,000,000 cu. yd. of concrete. A hammer-mill plant for the manufacture of sand from quarried rock was indicated as the most economical method of providing this material. The abrasive character of the feed as compared to the average hammer-mill feed made it necessary to control operations rather closely, and this resulted in the accumulation of many data hearing on production and maintenance. This paper will deal only with three specific sets of data, accompanied by such general information as may be necessary to explain the conditions under which they were obtained and followed by discussions on the relation of silica content to hammer wear, comparative costs of slugger and stirrup hammers, and comparative costs of tool-steel and manganese-steel grate bars. Coarse Aggregate Aggregate for the concrete poured at Norris Dam came from a dolomite quarry within 2000 ft. of the west abutment of the dam. Geologically this rock is known as a Knox dolomite. A typical chemical analysis is given in Table 1. Table 1.—Typical Chemical Analysis Per Cent H2O, 110° F............................................. 0.02 lgnition loss.............................................. 43.56 MgO.................................................... 19.19 CaO ................................................... 29.07 Fe²O³.................................................... 0.39 Al2O³ .................................................. 1.94 SiO2..................................................... 5.75 SO2...................................................... Tr. Rock was carried by 12-yd, dump trucks to a 42-in. gyratory crusher set at 6 1/2in. The product of the primary crusher was taken by a belt conveyor to a double.-deck vibrating screen followed by a 5 1/2-ft. cone

Jan 1, 1938

By Francisco Cadena

The construction of Norris Dam, built by the Tennessee Valley Authority on the Clinch River, a tributary of the Tennessee River, involved the production of coarse and fine aggregate for approximately 1,000,000 cu. yd. of concrete. A hammer-mill plant for the manufacture of sand from quarried rock was indicated as the most economical method of providing this material. The abrasive character of the feed as compared to the average hammer-mill feed made it necessary to control operations rather closely, and this resulted in the accumulation of many data hearing on production and maintenance. This paper will deal only with three specific sets of data, accompanied by such general information as may be necessary to explain the conditions under which they were obtained and followed by discussions on the relation of silica content to hammer wear, comparative costs of slugger and stirrup hammers, and comparative costs of tool-steel and manganese-steel grate bars. Coarse Aggregate Aggregate for the concrete poured at Norris Dam came from a dolomite quarry within 2000 ft. of the west abutment of the dam. Geologically this rock is known as a Knox dolomite. A typical chemical analysis is given in Table 1. Table 1.—Typical Chemical Analysis Per Cent H2O, 110° F............................................. 0.02 lgnition loss.............................................. 43.56 MgO.................................................... 19.19 CaO ................................................... 29.07 Fe²O³.................................................... 0.39 Al2O³ .................................................. 1.94 SiO2..................................................... 5.75 SO2...................................................... Tr. Rock was carried by 12-yd, dump trucks to a 42-in. gyratory crusher set at 6 1/2in. The product of the primary crusher was taken by a belt conveyor to a double.-deck vibrating screen followed by a 5 1/2-ft. cone

Jan 1, 1938

Australis Mining N.L. operates a continuous mode carbon-in-pulp (CIP) gold plant, processing sand and slime tailings from previous gold mining operations in the Norseman area. Plant design is that of conventional countercurrent contact between pregnant pulp and activated carbon. Gold desorption is achieved by the Zadra process using near boiling tempera- tures and atmospheric pressure. Process water is drawn from nearby Lake Cowan (saline). The plant operates at, or above, design specification of 400 dry tonnes per day. This paper describes the plant design and operating processes utilised in optimising throughput and gold recovery. TNTDnPTTnmTnM Favourable world gold prices and substantial reserves of sand and slime tailings prompted Australis Mining N.L. to construct a gold extraction plant during 1981. The projected plant throughput was set so as to complete treatment of available tailings over a three year period. Metal- lurgical tests indicated that, with a regrind facility satisfactory gold recovery could be achieved using a countercurrent CIP process. Reflecting the entry of Australis Mining N.L. into its first large scale treatment operation, the plant design emphasised simplicity but effectiveness of Operation.

Jan 1, 1982

By Gregg R. Gitschlag

There are more than 4,000 oil and gas structures present in the U. S. Gulf of Mexico. Approximately 100 structure removals occur each year and 66% of these are removed with explosives. From 1993-1995 an intensive study was conducted on the fish kill resulting from the explosive removal of 6 platforms off the Louisiana coast in water depths from 14-28 m (45-92 ft). After explosives were detonated, all floating fish and a sample of the dead fish which sank to the sea floor were collected.

Jan 1, 1997

By D. B. Reger

DAVID B. REGER.-T Want to 'add that since this paper was prepared a well is now being; drilled it the location recommended do the last page. It was not, however, done at my instance; it was done at the instance of Dr. White, the State- Geologist of West Virginia, who has been trying for several years to induce the large oil and gas companies to make a test of some of these, deep sands in West Virginia and a well is now just being started in Wood County, right at this immediate

Jan 4, 1917

By N. T. Rempe

The underground voids that result from mining provide opportunities for deep geologic waste disposal (DGWD). Such disposal could solve many environmental problems. DGWD takes careful planning, technology transfer and true partnership between waste generators and mine/repository operators. The US government is now planning on using specially mined excavations to dispose of radiotoxic and mixed waste. Using the experience gained from the domestic projects that are now in preparation and from foreign repositories that are now in operation, US mines can claim their rightful share of the growing market for DGWD.

Jan 1, 1997

By M. Orchin

THIS PAPER is concerned with two aspects of the behavior of coal: (1) Dispersion by solvents atmospheric pressure and high temperature and (2) the destruction and regeneration of the coking properties of coal. Several pure polycyclic compounds and a coal-tar fraction were found to extract 95 percent of the organic material of a bituminous coal. About 20 percent of the extract was soluble in benzene, and this fraction contained the ?coking principle? of the coal. From an extensive chemical spectroscopic, and x-ray study of the benzene-soluble material, some conclusions could be drawn concerning the composition and structure of this fraction of coal. A possible commercial application of the extraction technique is in the preparation of low-ash carbonaceous material for the manufacture of electrode carbon.

Jan 1, 1951

By Q. Cao, A. Pitts, L. Nastac

Accurate prediction of the desulfurization behavior of steel is of great importance for process control during ladle metallurgical furnace (LMF) steel refining. A CFD model capable of simulating multiphase flow with bulk and free surface turbulence phenomena and desulfurization behavior in the gas-stirred ladle has been developed. The fluid flow behavior shows that slag and metal try to entrap each other, forming a two-phase mixing zone. The resulting substantial contact area between the two phases will provide very favorable kinetic conditions for chemical reactions. For reaction kinetics model, the reactions at the metal/slag bath interface as well as the entrapped droplet surface are included. Predicted results show that the sulfur content changing with time in the ladle agrees well with the industrial-scale experimental measurements.

Mar 1, 2017