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By E Claridge

There are a number of major infrastructure tunnelling projects currently underway or proposed in New Zealand, including construction of new road and rail facilities and the refurbishment of existing road tunnels. These new projects have triggered a rethink of traditional practices in underground fire and life safety and local regulation.While there is a current surge in activity, tunnels have been a signifi cant part of New Zealand’s transport infrastructure for over a century. Despite this background, the new projects commonly face challenges that are symptoms of a national regulatory environment that has aspects that are inappropriate for underground environments. There are inconsistencies in local regional regulation and an absence of national guidance and standards relating to tunnel design. Historically, New Zealand has looked across the Tasman for guidance. Although recent overseas tunnel designs present learning opportunities, the adoption of international best practice and standards may not necessarily address local expectations or needs.This paper explores a number of specific matters affecting the design of road and rail tunnels in the New Zealand context, namely; the Building Regulations and associated local consenting processes and parties, and the responsibilities and needs of the New Zealand Fire Service.The discussion highlights the importance of a collaborative approach involving the designer, asset owner, regulators, emergency services, and other parties, and ensuring up-front clarity in design responsibility and ownership of residual risk.

Mar 8, 2011

By Liu Y, Campbell K. R

The paper shows how breakage parameters may he extracted from laboratory batch grinding results and how they may used with reference full-scale hall mill circuit data to estimate the likely size distributions of values and gangue in a full-sca

Jan 1, 1997

By Moore A. J

This paper describes the use of a wavefront reinforcement model which has been developed to supplement established charge mass scaling methods. The model allows for the time taken for blast vibration wavefronts to travel from each blasthole, and has been successfully used to explain the reason for directional increases in both air and ground vibration in certain situations. The model has been used to identify wavefront reinforcement due to the propagation of air vibration and ground vibrations in certain situations. The paper includes a throw (or cast) blasting case history which provides multi-station evidence of the strong directional nature of wavefront reinforcement.

Jan 1, 1995

We all live in professional silos û comfort zones, where we talk to like-minded people with the same training, experience and view of the world. We note in passing the existence of other disciplines, but they are tolerated rather than embraced. To the geologist, the metallurgist is a mad scientist conjuring gold out of some foul solution about which the less said the better. To the metallurgist, the geologist is a bearded, self-appointed sage who guesses what is under our feet by sniffing the air, and drives a Land Rover badly. As to the view of mining engineers held by both geologists and metallurgists, this is best left to the imagination. And of course we are all confused by the term æmetallurgistÆ. I am called a metallurgist though my skills are in mineral processing not metal processing, but I canÆt be called a mineralogist because that definition is already taken. *Please note that this is available as an extended abstract only*

Jan 1, 2005

By M K. C Roberts, M G. Magwaza, J W. L Hanekom, P Piper, R Lousteau

Due to the perceived potential to extract the second economic manganese seam at its Black Rock Operations in the Northern Cape Province, South Africa, Assmang commissioned an investigation with respect to mining method and sequencing of the two orebodies in 2007. Based on this initial study into multiseam potential, conditions and impacts, the rock engineering aspect was expanded to determine conceptual rules to govern the extraction of both manganese seams using the normal bord-and-pillar layout implemented at this operation. This work included the theoretical analysis using basic pillar design practices and numerical modelling, including the use of Map3D, UDEC and Phase2 codes.In 2013, Assmang launched a large-scale investigation into the potential to increase mine output from all possible manganese sources at the operation. Included in this investigation was the requirement to confirm or modify the conceptual multiseam extraction rules to implementation. As part of this confirmation process, stress measurements, borehole camera audits and additional numerical modelling were performed at a particular site on the operation where a limited extraction of both seams had been undertaken. The results obtained from this process provided confidence in the conceptual extraction rules and allowed the derivation of final extraction rules that will be implemented at the operation as the multiseam mining process becomes more widespread.CITATION:Hanekom, J W L, Roberts, M K C, Magwaza, M G, Lousteau, R and Piper, P, 2014. Confirmation of multiseam extraction rules for Black Rock Manganese Operations, Assmang, Northern Cape, South Africa, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 107–116 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By R Bunduwongse

The oil crisis had repercussions throughout the world and most importantly on mining, where the drive to reduce the use of liquid fossil fuel led directly to the appearance and subsequent growth in the design of mobile crushers in late 1970s early 1980s, which heralded a new era in both quarrying and mining. Even though mobile crushing has now become common, even preferred in the quarrying industry, this has not been the case in mining. This paper looks at why, in spite of the initial optimism, this technology has yet to gain full acceptance in the mining industry. The paper examines some of the problems that have been encountered in the past and offers suggestions as to how they can be avoided by applying the appropriate technology. It then takes a look at the successful application of the semi-mobile in-pit crushing system used by Italian Thai Development Company (ITD), on the Mae Moh Phase 5 contract and examines how the techniques used successfully there could be applied to the industry at large.

Jan 1, 2007

By Peck J. P, Kennedy D

Drill performance monitoring studies were recently completed at the Fording River mine, British Columbia. Microprocessor-based instrumen- tation and data analysis techniques were developed with the objective to improve short and long term mine planning. Data analysis permitted the identification of thicknesses and interfaces between soft/hard zones at depth based upon the recorded responses of the drill. Data clearly con- trast the soft coal seams and harder waste rock units based on variations in recorded drill rotary speed and torque, hydraulic downpressure, bail- ing air pressure and instantaneous rate of penetration. These parameters were monitored and recorded at 10 cm sampling intervals. Processed drill data was correlated with gamma logs, an existing means for locating coal seams and distinguishing between waste units. Current development of a pattern recognition module aims towards automated interpretation of drill data, identifying micro-and macro-geological and geomechanical rock mass characteristics. Delay between acquiring, processing and interpret- ing the drill data for practical use by mine personnel should be minimized. Integration of this technology with the mine's current main-frame based Mine Engineering Application System software will enable more accurate and timely annlication of the nrocessed drill data.

Jan 1, 1989

By K M. P Singh, K M. K Sinha, G S. Jha, T Gouricharan, K K. Sharma

The majority of the powerplants in India are fed with non-coking coals, with the coals dispatched from their respective mines via wagons loaded by a rapid loading system or pay loader. The usual top size of coal is 200 mm and sampling is carried out manually from wagons. The manual method of wagon top sampling of large size raw coal is not only difficult, but also violates some of the fundamental principles of sampling. As per sampling requirements, samples are to be drawn from the full depth of the wagons, which is impossible to be done manually. Since the ash distribution in the different size fractions is not homogeneous, the results from the samples, which do not reflect the true size distribution of the lot, are likely to be biased. More importantly, sample collection by shovel from the top is a function of human discretion and not governed by the equiprobability rule. In another case, the sample has been collected by a cross belt-type auto mechanical sampler for 200 mm size coal at one of the super thermal power stations. Test analysis shows that coal collected using a cross belt-type mechanical sampler also has significant deviations from stopped belt coal samples of 200 mm size due to size segregation. Studies carried out on wagon top sampling through specially designed experiments reveal some interesting features. The presence of bias in wagon top sampling is apparent when compared with the ‘stopped belt’ sample. In this paper, a comparative study between manual wagon top sampling/auto mechanical sampling with respect to stopped belt sampling has been conducted for coal of size 200 mm. In addition, precision studies have been performed for wagon top sampling/mechanical sampling for Indian thermal powerplants.CITATION:Sinha, K M K, Sharma, K K, Jha, G S, Singh, K M P and Gouricharan, T, 2014. A comparative study of manual wagon top sampling and auto mechanical sampling of 200 mm size coal with respect to stopped belt sampling of thermal coal at Indian super thermal powerplants, in Proceedings Sampling 2014 , pp 43–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

The elements of consistent structural de sign models for underground structures are explained. Such models should comprise at least ground properties, excavation and support methods, computational models for analysis, failure hypotheses, and in-situ monitoring. The fundamental characteristics of the interaction between ground and support are investigated. Then, plane strain models for soft ground tun- nelling and design models for rock tunnelling employing stress release at the tunnel face are elaborated. Some numerical evaluations are gi- ven in diagrams, comparing approaches of dif- ferent authors. Comments are presented on nume- rical three-dimensional models (visualized by structural models for mining in rock salt), on the interaction of in-situ monitoring and design, on structural safety for underground structures, and finally on the general develop- ment of structural design models in geo- Techniques.

Jan 1, 1987

By Fowke NC, Williams RJ, Hungerford F

In-seam, directional drilling has been implemented at Huntly West Mine, New Zealand as the most cost effective means of obtaining geological information at a level of detail and accuracy required for planning of longwall ("flexiwall") panels. No geological or geophysical technique tried at the mine prior to 1989 has been able to reduce geological risk to an acceptable level. Surface and in-seam seismic methods have not had adequate resolution. Obtaining the required knowledge via surface drilling would be prohibitively costly, and still not precisely locate or orient faults or the axes of seam "ridges and valleys".A total of 3543 m was drilled at an average of 67m/shift including setting up time. Unplanned delays totalled only 9.6 percent. Major re-interpretation of seam structure resulted from the drilling. Lateral and longitudinal panel grades have been defined. which should be negotiable with the Coalcorp longwall equipment.

Jan 1, 1991

The problems of the as-built water supply system are discussed. Recent modifications to the collection dams and the water cleaning station using wedge wire screens to resolve these problems are outlined.

Jan 1, 1978

By Howarth W. J, Sowerby B. D, Watt J. S

On-line analysis systems have found widespread application in the metalliferous mineral and coal industries. The continuous analysis and rapid response of these systems has led to improved control of mining, processing and blending operations, with increased recovery of valuable minerals and coal combustibles.The paper reviews developments in on-line analysis by CSIRO and Mineral Control Instrumentation Ltd which led to the award of the Australia Prize 1992. These commercialised systems analyse mineral and coal slurries; determine the ash and moisture contents of coal on conveyors, and the moisture content of coke on conveyors; and determine the carbon content of fly ash. These gauges are estimated to have resulted in productivity increases valued at $50 million per year to Australia.

Jan 1, 1993

Data logged on mineral beneficiation processes during normal operation are analysed using time series (correlation and spectral) methods to identify the dynamics of the processes for on-line computer control. Recursive least squares estimation techniques are used to identify parametric models for a cassiterite flotation circuit and a coal washery. Identification problems such as the determination of model order, process time delays and the 'contamination' of the data by process recycle streams (feedback) are discussed. Typical results are presented in which optimised models are identified from data logged during normal operation.

Jan 1, 1985

By W Mahoney, F Clement, E Saraiva

Prefabricated waterproofing sheet membranes are extremely complicated to install in underground sections with complex geometries and, despite being already subjected to quality tests in the factory, the installed membrane often exhibits leakages due to different reasons. Main sources of leaks are the required high amount of welding seams and damages caused during installation of reinforcement, as well as overstretching and poorly installed secondary concrete linings. Also the design of the tunnel lining is strongly influenced and limited by the use of prefabricated waterproofing sheet membranes. The use of sprayed waterproofing membranes for more than a decade has contributed to durability and serviceability, as well as to increasing sustainability of tunnel linings. The presented sprayed waterproofing membrane MasterSeal 345 is an advantageous alternative to prefabricated waterproofing sheet membranes under typical tunnelling conditions, especially in geometrically complex areas, such as in lay-by niches, cross passages and crossover caverns, where installation of conventional waterproofing membranes is inherently difficult, and locating leaks is challenging. This membrane has been successfully used in underground projects with different waterproofing design concepts and under diverse hydro-geological and environmental conditions for over a decade. It provides tunnel designers with different options and optimisation for the design of the tunnel concrete lining. Additional advantages to owners, contractors and designers from the use of the sprayed membrane include flexibility in the design, increased productivity and flexibility in working programming, as well as improved logistics, resulting in significant program and cost savings and reduced long-term maintenance costs. This paper describes the key features of this sprayed waterproofing membrane, its application range and limitations, the waterproofing concept, design options and related benefits. Further, guidance for membrane application and quality control and a summary of two recent project references in the United Kingdom and in Switzerland are provided.CITATION:Saraiva, E, Clement, F and Mahoney, W, 2014. The use of sprayable waterproofing membranes in underground structures – concept, design options, benefits and limitations, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 323–332 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

How often does one hear that a recent feasibility study was not a success? Alternatively, when scope of the feasibility study was sent out to tender there was a large discrepancy in tendered prices. If the tendered prices were to be compared to the consumer market, for instance the purchase of a car, where the concept is transport in a controlled and safe manner, prices vary by large factors, but then so do the specifications. In the case of a feasibility study, prices should be within a tighter margin as the tenderers are all quoting against the same concept and specification. Why do these discrepancies occur? Price discrepancies will in every likelihood be attributed to two main factors; one, the perceived amount of work and two, the ability of the bidder to carry the risk associated with the feasibility study. It is, therefore, important that the scoping of the feasibility study covers the detailed requirements as clearly as possible stating what level of accuracy is required. The feasibility study is one of the first activities in the life of a project. The study, like the project it is investigating, is subject to the constraints of time, cost and quality. Its primary objectives are to demonstrate the viability of a project within the outlined scope and constraints.

Jan 1, 1998

By Zeni J. T

Gold was mined from quartz bodies at Ballarat East from the 1850s until closure of the last mine in 1917. The average depth of mines was about 350 m.Ballarat Goldfields Limited (BGL) carried out diamond drilling from surface between 1985 and 1987 which proved the continuation of gold-quartz mineralisation beneath the old mines.During 1989 an underground development program was commenced to access the mineralisation for detailed exploration. The program included two simultaneous shaft developments. These were known as B2 shaft and Llanberris No.1 shaft.

Jan 1, 1992

By S Mitra, D O’Dea, N Barrett, T Honeyands, P Zulli

The steel industry continues to explore and demonstrate technologies that decrease its greenhouse gas emissions, especially in blast furnace ironmaking where alternate operating conditions will be required. As the furnace has been optimised over many years, it is approaching the minimum fuel rate possible with coke and Pulverised Coal Injection (PCI). Alternative operating conditions are therefore required to further decrease greenhouse gas emissions. Because of this, hydrogen has been proposed as a reducing agent in the blast furnace. Injection of hydrogen through the tuyeres was assessed using a comprehensive 2D blast furnace global model. The model was calibrated to a blast furnace operating with PCI as a base case and various approaches to hydrogen injection assessed, with a particular focus on displacing PCI. The maximum hydrogen injection rate of 19.5 kg H2 per tonne of hot metal was predicted, limited by decreases in the raceway adiabatic flame temperature and top gas temperature. Internal blast furnace conditions, such as gas composition and reduction degree were also predicted. Holistic analysis was performed to estimate the effectiveness of hydrogen injection on reduction of greenhouse gas emissions. Based on these results, the changes in blast furnace operation and emissions under hydrogen injection are discussed.

Nov 8, 2021

By Knasmillner

During blasting body wave interaction with geometrical surfaces induces Rayleigh-waves which propagate along free surfaces, e.g. crack faces or delaminated rock layers. These Rayleigh-waves carry most of their energy within a very shallow surface layer and propagate with very little attenuation in real rock materials. Upon interaction with a crack front a very strong mixed mode stress intensity factor may result and lead to fracture initiation. On the basis of experimental photomechanical results the history of dynamic stress intensity factors Kt and K2 will be studied in Detail.

Jan 1, 1990

By Ellery B. I

Field investigations recently undertaken by Utah Development Company (U.D.C.) have been developed to allow the assessment of ground conditions relevant to the use of large bucket wheel excavators for pre-stripping overburden. "Bucketwheel diggability" predictions were made on the basis of a wedge test which was perform- -ed in the field on nominal 150 mm diameter drill core samples. Specific separation force (calculated from the wedge test results) for different rock horizons were theoretically related to the excavation rates of various sized bucketwheels, i.e., "bucketwheel diggability". The specific separation force was shown to vary with lithology, structure, weathering and moisture changes. By correlating these features between boreholes, an overall assessment of bucketwheel diggability was then made. The approach adopted to assess bucket- wheel diggability incorporated various levels of investigation. Initially, a reconnaissance stage provided information from widely spaced 150 mm cored holes to compare and contrast areas with differing bucketwheel digging char- -acteristics. The following stages progressive -ly added to this information, until finally, between hole correlations, allowed calculations to be made of volumes of materials of similar

Jan 1, 1981

LESLIE BRADFORD GOLDEN JUBILEE ORATION "Not only a metallurgist but a scientist of the highest order" Leslie Bradford and the Australian Metallurgical Industry

Jan 1, 1987