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By Grossi M, Baiden G

This paper describes a new mine backfill method based on a newly invented binder with several years of test results from laboratory and on- site applications. The new binder has several advantages over traditional Portland and slag cement binders. One tonne of the new binder can replace two to three tonne of Portland cement when used to consolidate backfill and can result in the same compressive strength within seven days. When comparing backfill slurries of the same pulp density, the new binder attains more volume of in-place backfill mass than Portland cement because of the high crystallisation of water, resulting in tightly filled stopes. The crystallisation of the water provides for less or no de- watering in the backfill stope and easier transportation of the backfill slurry. Pastefill performance can be achieved by using pulp densities typical of a hydraulic backfill and the new binder, all the while transporting with the same ease of hydraulic fill.

Jan 1, 1998

This paper examines the complex interplay of deposit characteristics, mining plans, tailings disposal techniques and rehabilitation requirements on planning for mineral sands operations. All component parts of this mining cycle are interdependent and cannot be evaluated in isolation when optimising a mineral sands operation. This is most evident when projects are large-scale or involve resources that contain complexities such as high slimes content, consolidated hard band materials, acid forming materials and radioactive materials. Projects located in environmentally sensitive areas add further to the need for more stringent planning. This paper describes the analysis techniques adopted by Hatch to evaluate mining and tailings placement options for a dredging and floating concentrator system. The principles and methods used in the analysis are applicable to any mining system involving the complexities listed above. The focus of this paper is on the reconstitution of mined material as tailings and the impact of this process on mining schedules and tailings construction and placement options.

Jan 1, 2001

From time to time lead, which is normally considered to be a soft ductile metal, fails by cracking. The cracks which form appear to be of two distinct types-(a) those which follow a zig-zag course around the boundaries of crystals and (b) those which follow a more direct path, frequently two systems of cracks appearing at right angles.The former appear definitely to be associated primarily with the properties of the crystal boundaries, whilst the latter appear rather to be determined by the system of stresses applied. In both cases the lead appears to be a brittle rather than a ductile metal, for the failure occurs without the large amount of deformation usually associated with the tensile breaking of lead. The latter is, however, a function of time and when lead is deformed by long applications of stress, the metal appears to- be less ductile than when the stress is applied suddenly. Thus, if a given test piece of commercial lead is broken by a stress of 1100 lb. per sq. in. in several hours, it may extend 40 to 50%before failing, whereas when broken by a stress of 500 lb. per sq. in. acting for 12 months or more it willshow an extension of only 15 to 25 %. With lower stresses still, failure would take much longer and undoubtedly lower extensions would be obtained.As the stress is lowered it is found that the marked local contraction characteristic of ductile metals becomes less noticeable, and failure, instead of being by extension of *Lecture delivered to the First 'Ordinary Meeting of the Australasian Institute of Mining and Metallurgy, 21st August, 1935.

Jan 1, 1935

Largely inherited from the past and from strictly internal laboratory use, the certification of reference material using round-robin assaying is often insufficient for the use made today for external assay laboratory control by client parties. Certification often needs to be revisited on the basis of existing round-robin data, especially to derive reproducibility parameters to the end of establishing probabilistic performance gates for operational error detection on a batch per batch basis (ie batch-ærejectionÆ). The most common difficulty arises when only a few certification samples have been analysed in one single batch by each laboratory, so that the round-robin data do not contain the full variability that needs to be quantified. Existing certification data sets from properly submitted round-robin samples were studied using analysis of variance to derive a remedial method, leading to the proposal of default correction factors to restore full variability estimates when no other avenue is available.

Jan 1, 2008

By Manula C. B

The total systems model for underground oal mining planning and design is a set of omputer programs which encompasses a realis- ic reproduction of the interaction between he geological, environmental, equipment, meth- ds and the health and safety aspects of the ining plan. The total system includes nine ajor subsystems - Geology and Reserves, Meth- ne Generator, Roof Support, Subsidence, Pro- uction, Rail Haulage, Cost, Water Generator, nd Ventilation. The subsystems themselves re divided into two categories based on the requency with which they are executed. Event riented Subsystems are executed either inde- endently, or at discrete intervals when cer- tain specific events occur. Dynamic subsystems 'unction interactively during the production :ycle. They transfer data to or request data `rom event oriented subsystems only when spe- ific events occur. Three specific areas for iodel application are in the measurement of system performance, the development of the '_ nterrelationships of the components of deep Wining process and the evaluation of new and Lnnovative mining technology.

Jan 1, 1977

By Lawson F

Pyrite concentrate and calcine from the Nanjing Lead-Zinc-Silver Mines, China, were leached with aqueous cyanide and thiourea solutions. More than half of the contained gold and silver was able to be extracted from the roaster calcines. The very fine dissemination of precious metal grains, high roasting temperature (850 - 900°C) and residual sulphur are believed responsible for the Iow extractions.A recovery of about 70 per cent for both silver and gold was able to be obtained with cyanide and with thiourea leachants when the pyrite was roasted in the laboratory at temperatures between 600 and 650°C.Thiourea, as an alternative leachant, has received much attention recently and a series of constant potential leaching tests was conducted.When the thiourea to formamidine disulphide mole ratio was about two, the precious metal extraction was greatest. In the Nanjing calcined material, this occurred at a potential of about 210 mV relative to a standard calomel electrode.

Jan 1, 1987

By Basillo CI

The adsorption mechanisms of various thiol collectors can be subdivided into four classes: chemisorption, EC-mechanism, catalytic oxidation and metathetical substitution. The chemisorption mechanism occurs at potentials below the thermodynamic potentials for the metal-thiol compound formation and is reversible. The EC-mechanism occurs when the mineral is sufficiently oxidised to liberate metal ions to form metal-xanthates; therefore, it is observed with more easily oxidisable minerals and/or with collectors having large pK values. Thionocarbamates adsorb on sulphide minerals via the EC-mechanism due to their large pK values. Although the adsorption occurs at very low potentials as compared to xanthates, it is irreversible with large overpotentials. On the other hand, the adsorption of modified thiophosphates and thiophosphinates occurs near the thermodynamic potentials because of the low pK values. The metathetical substitution is believed to occur only when a mineral is highly oxidised. These classifications are useful for studying the effects of electrochemical potentials and the molecular structure on the collector adsorption Mechanisms.

Jan 1, 1993

By Mansor A. N

Results are reported for the computer simulation of heap leaching of mixed copper oxide and sulphide ores. They resemble those obtained from testwork in terms of a substantial peak in the copper concentration of the pregnant solution, an initial period when no copper emerges and a lengthy period towards the end when the copper concentration and the daily increment in copper recovery are low. The simulation can be used to forecast process results before any column or similar testwork is performed. Potential applications of the simulation to process design, operating strategy and optimisation are discussed. Three modes of operation are identified that correspond to different performance patterns and dependencies on ore and process variables. The relative merits of different operating strategies for approaching the ideal performance are being investigated. For process design and development purposes, the simulation may be used with a limited testwork programme to achieve significant savings in time and resources.

Jan 1, 1989

During 1995 a catastrophic accident took place at the No 2 Vaal Reefs shaft in South Africa, when a locomotive fell onto a cage, causing the death of 104 people. The subsequent Commission of Enquiry found that the safety detaching hook had opened when hit by parts of the falling locomotive, detaching the cage from the rope and allowing the cage to drop 400 m down the shaft. It was believed that had the hook not detached, the rope would have been sufficiently elastic not to have failed, implying that many fatalities may have been avoided. In addition, the risk of accidental opening of hooks due to impact with smaller falling objects in shafts became a concern. This paper deals with a comprehensive statistical investigation that was performed to quantify this risk, establish acceptable levels of such risks and to derive criteria for the resistance of detachment hooks against accidental opening caused by impacts. The investigation involved a survey, dynamic finite element analyses and Monte Carlo simulations.

Jan 1, 2005

By M Grossi, G Baiden

This paper describes a new mine backfill method based on a newly invented binder with several years of test results from laboratory and onsite applications. The new binder has several advantages over traditional Portland and slag cement binders. One tonne of the new binder can replace two to three tonne of Portland cement when used to consolidate backfill and can result in the same compressive strength within seven days. When comparing backfill slurries of the same pulp density, the new binder attains more volume of in-place backfill mass than Portland cement because of the high crystallisation of water, resulting in tightly filled stopes. The crystallisation of the water provides for less or no dewatering in the backfill stope and easier transportation of the backfill slurry. Pastefill performance can be achieved by using pulp densities typical of a hydraulic backfill and the new binder, all the while transporting with the same ease of hydraulic fill.

Jan 1, 1998

By Matsushita Y, Maeda M, Sano N

The present study was carried out to explore the possible separate recovery of iron and phosphorus (as gas) from BOF slag using graphite crucibles or graphite powders in the presence of a tin bath. The last is consider- ed to enhance the activity of phosphorus in iron reduced from slag or not to absorb the phosphorus vapour readily. When the slag was reduced in a graphite crucible in contact with a tin bath, the phosphorus reduced from the slag was carried away in CO explosively generated by the reduc- tion of iron oxide. When graphite powder was used as the reductant instead, 78% of the phosphorus was removed from slag, only 3% of which was absorb- ed into the tin bath. The rest left the system as gas. Gaseous dephosphorization depends on the area of contact between slag and reductant as cll n.u the amount of the latter. the reduction behaviour was directly observed, using an X ray transmission technique, to conlirm the reaction mechanism.

Jan 1, 1980

Mine production planning and scheduling as a production planning problem can be handled using Linear (Goal) Programming. This approach is particularly useful when the product quality is important. This has been shown for many mine planning cas

Jan 1, 1998

THE Wonthaggi coal-field lies south easterly from Melbourne at a distance by rail of 86 miles, on the flats of the Powlett River, immediately to the south of the deep-cut valleys and steep intervening ridges in the Jurassic rocks of the Bass Range and itsfoot-hills. The coal-bearing area is covered with a thin layer of late Tertiary and Recent deposits, which serve to mask the true character of the underlying coal-bearing rocks and effectually prevent the appearance of any coal outcrop. Two or three bores sunk prior to 1890 had shown the locality to be really a potential coal-bearing one. Only one additional bore was sunk in the State Coal Mine area until 1908, when energetic boring was resumed, with the result that in November, 1909, when an acute shortage of black coal in Victoria resulted from the prolonged strike on the New South Wales coal-fields, coal-seams had been located at Wonthaggi offering sufficient inducement to start an...

Jan 1, 1918

Drilling and blasting operations have historically been viewed as a necessary 'evil' part of mining, whose costs should be minimised by whatever means possible. In the past, when operations depended primarily on crushing and milling for ore re

Jan 1, 1998

In 1952 when universities imposed fees on students and most students won either Commonwealth or Government department or private scholarships to study, I won a scholarship to study mining engineering at the University of Technology in Sydney. The univ

Jan 1, 1994

By Guerney P. J

A suspension of finely powdered ferrosilicon in water is the dense medium used in the gravity upgrading of iron ore, diamonds and other minerals. Ferrosilicon can he lost in the plant through corrosion. The greatest corrosion losses occur when

Jan 1, 1997

This paper attempts to put into perspective the implications of the legal disclosure requirements for promoters and consultants when making statements concerning ore resources and reserves. The need to take account of non-technical as well as technical factors is highlighted.

Jan 1, 1987

Zinc enters into solution on aeration of sphalerite in deionised water. It has been observed that less zinc dissolves in a copper vessel than when the same operation is carried out in a glass vessel of similar shape and size.

Jan 1, 1980

By H Arvidson, J Vann

When only wide-spaced drilling is available, for example at concept, prefeasibility and feasibility stages, properly implemented linear estimation (including ordinary kriging) predicts grade tonnage relationships that are over-smoothed compared to final production estimates (and production). Non-linear estimation and conditional simulation are alternative geostatistical approaches that can provide more reliable estimates of the recoverable tonnage and grade from wide-spaced drilling. Non-linear estimation and conditional simulation have been rarely used on iron ore deposits. However, these techniques have had wide application in other commodities such as gold and base metals. Conditional simulation has been used in the iron ore industry (eg Guibal et al, 1997); however, its use here is outlined as a means of generating non-linear estimates, not just its use for variability and drill spacing analysis. As a rule, regardless of commodity, the decision to use non-linear geostatistics will necessitate increased skills and require more time. This decision must therefore be justified in terms of cost-benefit. Such cost-benefit analysis is not straightforward, and to help an approach for determining when linear estimates are inadequate is presented. Recommend in this paper is a well-established non-linear geostatistical approach, the global ædiscrete Gaussian modelÆ (DGM) of change of support, as a tool to establish whether moving from linear to non-linear estimates will materially improve estimate results. Also discussed is the additional use of DGM as a block model validation tool. One specific factor contributing to the lack of application of non-linear geostatistical methods in iron is the added difficulties that arise when conditional simulation and non-linear estimates are required to reproduce the numerous and often important correlations between variables in iron ore deposits. Consequently, presented in the paper is a synoptic review of non-linear estimation and simulation methodologies applicable to correlated variables.

Jan 1, 2007

By O Omidi, P D. Katsabanis

The effect of delay time on fragmentation has been discussed for a long period but rarely in a satisfactory and unbiased way. Despite the efforts of many researchers, delay selection for fragmentation improvement or optimisation remains a controversial issue. Large-scale tests have been plagued with scarcity and scatter of observations, while small-scale tests have been associated with boundary effects and energy losses. Theoretical work is often used to produce explanations for available measurements or tries to simplify wave propagation and wave interaction to guide observation and practical work. The present work analyses results obtained from a relatively large number of small-scale experiments in blocks made of grout, and re-analyses results of previous experiments, to conclude on the effect of delay on fragmentation. It is shown that the main contribution of the delay is found in the fragmentation of the larger fragments of the blast, while the small fractions show almost no effect. Samples, where copper liners were used to inhibit penetration of detonation products in the rock mass, showed effect of delay only when short times were used and steady but poor fragmentation when long delays were used. Based on small-scale experiments, it appears that the fragmentation is optimised when a hole fires prior to the radial cracks, produced by the previous hole, reach the free face of the blast. Gas penetration may result in the development of few more fractures that affect the fragmentation of the largest particles of the blast.CITATION:Katsabanis, P D and Omidi, O, 2015. The effect of delay time on fragmentation distribution through small- and medium-scale testing and analysis, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 715–720 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015