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By D. Scott Scovira, Karl Dufresne

Blasting in geothermally high temperature ground and/or extremely reactive ground is an increasing common challenge for surface and underground mines. Many current PETN based non-electric and electronic detonators have manufacturer published in-hole temperature limits ranging from 55°C to 65°C (131°F to 150°F). When confronting blasthole temperatures above the manufacturer published limits, operations may request site-specific guidance and qualification for use. The advised safe loading window for in-hole PETN based detonators is often too short to be practicable for production blasting. To overcome limitations of PETN based initiation systems, surface mines with high temperature ground and/or reactive ground are known to load blastholes with a qualified high temperature bulk emulsion that are top primed with a cartridge of temperature qualified detonator sensitive emulsion plus an RDX detonating cord downline. As there is no in-hole delay detonator in this system, blasthole timing is accomplished with surface delays. Although this system is safe, top priming and surface delaying does influence floor quality and top size fragmentation, and safe loading windows times reduce blast block size and increase blasting frequency. A mining company with a site characterized by geothermally high temperature ground plus highly reactive ground employed a blasting system like the one described above. The site desires to improve blasting performance by moving to an in-hole delay initiation system that can withstand the site ground conditions. At the request of the mining house, DynaEnergetics developed an electronic initiation system for application in geothermally high temperature ground and/or extremely reactive ground conditions. The DynaEnergetics IGNEO high temperature electronic initiation system is rated for in-hole use in ground up to 150°C (302°F) for 48 hours. The detonator consists of a high strength detonator with an HMX base charge and thermally resistant downline. To make up a primer, the detonator is inserted into a booster charge assembly that is fitted with a small HMX shape charge. This high energy primer is designed to be compatible and reliable for firing bulk emulsions, including those with high percentages of urea inhibition to combat reactive ground. Up to 1000 detonators may be programmed in 1 ms increments up to 1500 ms. The system is controlled by a digital firing panel that can be used with either a wired or wireless trigger. The system enables high temperature and/or reactive ground sites to utilize in-hole delay initiation and realize the associated performance benefits.

Feb 1, 2024

By Ovidiu Pasca

The Phelps Dodge Miami Smelter utilizes four Hoboken converters to process molten matte from the Isasmelt vessel. This paper presents past and present improvements in operation, maintenance and process optimization, based on data collection, which has led to increased converter campaign life and copper throughput.

Jan 1, 2005

By Harry Asche

The last 12 months has seen the construction of the first Earth Pressure Balance (EPB) TBM excavated tunnel in New Zealand on the Project Hobson sewer storage tunnel for Watercare Services Limited, with the concurrent excavation of the second EPB tunnel on the Rosedale Outfall project for North Shore City Council. Together these tunnels involve a total length of 6km and follow an 8 year pause in TBM activity in Auckland. TBM performance on these two projects is thus of significant interest as there are four major tunneling projects totaling over NZ$8B being planned for Auckland, in similar ground conditions. Auckland?s bedrock is a weak sandstone/siltstone (East Coast Bays Formation), subject to infilled paleovalleys. The geology in the region has been significantly influenced by volcanic activity; 49 volcanoes are present within 20km of the city centre. The paper describes the design and construction challenges for the projects, including TBM performance, ?sticky spoil? management, and risks associated with basalt lava flows and two paleovalleys. Watercare?s Project Hobson also saw the successful implementation of a Geotechnical Baseline Report?one of the first uses of this type of document in Australasia. Rosedale Outfall is designed for high internal water pressures with varying hydraulic flows, with the risk of exfiltration explicitly addressed.

By Bill Parnell

"Friction winders and double drum winders have been used in the vertical shaft mining industry for over 100 years. In that time, there have been many changes made in the electronic and mechanical fields of hoisting, but few changes made in the manufacturing and performance of steel wire rope, until recently.In the past ten years, with the advent of high polymer thermoplastics, the industry has seen some major advancements in steel wire rope. By incorporating a polymer with steel, improvement of rope life and reduction of costly maintenance downtime has been accomplished.IntroductionThe Williams Mine is Canada's largest gold producer with an annual production of some 500 000 ounces of gold from 2.2 million tonnes of ore. The Williams Mine is situated in the Hemlo area of northwestern Ontario, approximately 40 Ian east of the town of Marathon. It is operated by the Williams Operating Corporation which is owned equally by Teck Corporation and Homestake Canada Inc. It is one of three adjacent properties forming the Hemlo gold camp."

Jan 1, 1995

By R Verreet

In April 2000 Mount Isa Mines installed hoist ropes of a new design on the double-drum winder at their P49 shaft. The ropes, CASAR Duroplast, were about three times as expensive as the previously used triangular strand ropes. The P49 shaft is situated at Mount Isa MinesÆ George Fisher Mine, located some 30 km north of Mt Isa. This shaft used the tried and proven 6 x 33 triangular strand style ropes. The rope life attained by these ropes at the time was acceptable due to many years of satisfactory performance. The following study indicates the improvement of service life using CASAR Duroplast rope in P 49 shaft, which depends on shaft and winder parameters of that particular shaft and cannot necessarily be generalised to other shafts.

Jan 1, 2005

By Humphrey Dean

"Canadian mining companies now operate numerous Koepe-type friction hoists in a variety of different shafts, most of which have a depth in excess of 3,000 feet. Rope performance reliability is an absolutely essential ingredient of most installations and, for this to be provided, a more comprehensive understanding of rope reactions to applied stresses is required.It is the intent of this paper to illustrate for the operators the importance of the critical stresses encountered and to provide a maintenance program designed to circumvent potential difficulties."

Jan 1, 1970

HoistEM is a helicopter-towed time domain electromagnetic system. This paper presents details of the towed array structure (the Hoist) as well as a description of the instrumentation. A comparison between HoistEM and ground TDEM (from which HoistEM was derived) is given. Over 50 000 line kilometres of HoistEM have been completed to date and datasets for structural mapping, nickel, base metals, manganese, ground water and bathymetry are presented and discussed.

Jan 1, 2004

By J. A. Norden

MUCH has been written concerning the hoisting equipment of various mines -throughout the country, but most of the literature on the subject, if not all, describes equipment of extraordinary capacity and the small and medium-sized outfits have been neglected. The hoisting equipment here described is capable 'of handling about 1200 tons per day. It has not been worked, to capacity, but 600 to 700 tons, together with men and materials, have been handled in two shifts without any great effort. Only one shaft extends from the surface to the lowest levels of the mine; see Fig. 1. It is composed of three compartments, two of which are used for hoisting and the third for water, air, and electrical lines, and for sinking purposes. In 1909, this shaft was raised from the 1000-ft. (304-m.) level to the 700-ft. There a station was cut and an air hoist installed. At this time all mining operations were confined to the upper levels of the mine; that is; above the 700-ft. The. ore was-dropped to this level through chutes from the 300-, 400-, 500-, and 600-ft. levels and then lowered in cars on cages to the 1000-ft., which is the main haulage adit, the mill and railroad bins being about 3000 ft. from the shaft. Orebodies were, in due time, developed on the 1000-ft. level and below. Therefore, in 1913, the shaft was sunk to the 1150-ft. level and thereafter sinking was continued at regular intervals until the 1500-ft. level was reached. But, hoisting from the 1300-ft. level was a difficult, and slow process with the antiquated air hoist, so, in 1916, it was derided to raise the shaft to the surface and install a modern, electrically operated hoist. This was completed early in 1917 and the hoist was in operation in March of that year.

Jan 8, 1920

By R. E. Dye

Introduction Research concerning all phases of hoisting practice, but more particularly the causes and prevention of hoisting rope deterioration and the improvement of safety dogs 158 for shaft conveyances, has been carried on intensively for the past three years in the Province of Ontario. Prior to the hoisting accident at the Paymaster mine on February 2nd, 1945, there had been no fatalities in the Province due to a hoisting rope failure. It was probably on this account that little original research on hoisting problems had been undertaken here and that the mining industry had been content to look to British, South African, and United States investigators for new developments in this field. Except for the Paymaster accident this might still be the case since, in any industry, it is apparently necessary for a serious accident to occur before any extensive programme of preventive research is launched. When this accident occurred, the Government of Ontario, with the close co-operation of the Paymaster officials and the mining industry as a whole, took immediate steps to determine the cause. A five-man, non-industry committee, selected from the Faculty of the University of Toronto with Dean C. R. Young as Chairman, was appointed by the Government, and a three-man Committee consisting of R. D. Parker, General Superintendent of the International Nickel Company of Canada, Limited, R. L. Healy, General Manager of Wright Hargreaves Mines, Limited, and R. E. Dye, General Manager of Dome Mines, Limited, with the latter acting as Chairman, was appointed by the Ontario Mining Association.

Jan 1, 1948

By Christopher J. Bise

INTRODUCTION The transportation of men, supplies, and mined material from an underground operation is the connecting link between the mine plant and the surface plant. Unless the mine is accessed by a drift or adit, some form of hoisting system is necessary for slopes or shafts. This chapter will deal with the selection of wire ropes and hoists, two of the most important consider¬ations when designing a hoisting system for an under¬ground mine. WIRE ROPES General A wire rope is designed to transmit forces longitudi¬nally along its axis. Wire rope is used in a variety of mining applications because of its flexibility, high ten¬sile strength, and dependability. Shaft hoisting ropes and principal slope haulage ropes are usually custom-¬built; however, proper rope selection for slushers, car spotters, etc. should not be overlooked. Wire ropes for shafts and slopes, since they represent the life line for the mines, should be of the very highest quality improved plow steel. This quality is necessary to deal with the conditions of loading, winding, vibration, abrasion, and corrosion. Tables I and 2 display the specifications for the typical wire ropes used for mine haulage applications. The 6 x 19-class haulage rope is used for most hoisting where abrasion is not critical. On the other hand, where abrasion is critical, such as a slope application, 6 X 7-class haulage ropes are preferred. For other mining applications, manufactur¬ers' handbooks should be consulted. Selection The selection of a wire rope for a mining situation consists of simply applying appropriate safety factors to a calculated maximum rope pull and comparing the result to the listed breaking strength of the rope under consideration. Table 3 can be used for determin¬ing the minimum factors of safety for wire ropes. To determine the maximum rope pull, the following quantities must be known: the rope weight in pounds (x), the conveyance weight in pounds (y), and the weight in pounds of the load in the conveyance (z). These values are used to calculate the load due to gravity, the load due to conveyance friction, and the load due to rope friction. When these loads are added together, as shown in Eq. 1, the maximum (static) rope pull (RPS) can be derived:

Jan 1, 1986

By M. C. Young

The Ozark Lead Company operating facilities are located in Reynolds County at the south end of the "New Lead Belt" of southeast Missouri. Development of this wholly owned subsidiary of Kennecott Copper Corporation started in May 1964, with a six foot diameter by 1250 foot deep steel lined shaft. A 20-foot diameter, 1480 foot deep, concrete lined production shaft was collared in March 1968. Production from the facilities began that month and has reached a present average of approximately 6000 tons per day. This paper describes the fully automatic system used to hoist the lead-zinc ore from a depth of 1420 feet to the surface crushing and concentrating facilities, as well as the man and materials hoisting system which allows the lowering of large equipment into the mine. MINING Galena, sphalerite and some copper minerals are found in several mineralized zones of the relatively flat lying dolomite of the "Bonneterre formation". The mineable ore zones vary from 10 feet to 110 feet thick, from 200 feet to 1200 feet wide, and several thousands of feet on strike. Two-boom diesel-hydraulic jumbos equipped with rotary percussion drills are used for both development and production. The jumbos are used principally to open the room and pillar stopes, and a track mounted down hole drill is used to bench in areas where the ore thickness warrants. Explosives used are ANFO, dynamite, and water-jell which are detonated by electric blasting caps. Broken ore (and waste) is hauled by rubber tired transports to chuted transfer raises. Approximately every 500 feet, these raises connect the orebody to the 15 foot by 28 foot train haulage level below. Two twenty ton diesel-hydraulic locomotives haul 160 tons per trip to storage pockets which have a total storage of 1500 tons of material. From these pockets the material is fed over a 6 foot by 20 foot mechanical vibrating feeder which includes one 4 foot by 6 foot grizzly section to a 48 inch by 60 inch jaw crusher. The grizzly and crusher products are transferred horizontally 45 feet on a 48 inch conveyor belt, to one of two 750 ton storage pockets. The material can flow unimpeded into one pocket or be deflected into the second pocket by a movable rock filled hopper. LOADING POCKET The material in each storage pocket is controlled by six lengths of ship anchor chain. The upper end of the 20 foot chain is anchored behind a brow in the pocket, while the lower ends are joined by a header. The lower ends of the chains are raised by two electric powered marine barge winches using 3/4 inch cables. The crusher operator controls the raising and lowering of these chains from a console in the crusher station. The upper and lower travel of the chains is controlled by cams and limit switches on the winch drive. The winches are located within 5 feet of the shaft, and shaft water continually causes problems with the electric components. A malfunction in the upper travel switch will cause the winch to pull the chains into the cable sheave (breaking the cable or sheave), while the lower switch causes the winch to unwind too much rope. Serious consideration is being given to changing the electric motors to pneumatic, since pneumatic motors will eliminate the need of any electrics at the winches. The winches can be "bottomed out" against the sheave without damage to the cable or sheave when raising the chains, and can be allowed to "free wheel" to lower the chains. A surge pocket below the two storage pockets feeds material to two

Jan 1, 1975

By P. Crouse, J. Obermeyer

"INTRODUCTION Site location and history The Holden Mine is a former underground copper mine that was developed and operated by the Howe Sound Mining Company (Howe Sound) from 1938 to 1957. The mine is located in north-central Washington State, U.S., near Lake Chelan in the area shown as Holden Village in Figure 1. Although Rio Tinto never owned or operated the mine, they are managing and funding a several hundred million dollar clean-up to prevent future water and soil contamination and to reclaim the former mine site under the United States Environmental Protection Agency (USEPA) Superfund process. The former mine included an onsite mill and a nearby housing complex for the miners. Howe Sound developed the mine as a series of near-horizontal drifts and tunnels, interspersed with stopes and shafts that connect different mine levels underground. The tunnels that were excavated to develop the mine total nearly 100 km in length.During development of the underground workings, Howe Sound removed more than 230,000 cubic meters (m3) of waste rock from the tunnels and deposited this material in two waste rock piles. Ore was processed from the mine in the onsite mill to produce a copper concentrate that was shipped off site for smelting. Roughly 10 million tonnes of tailings were produced as a by-product of the milling operation, most of which were deposited in three large impoundments (Tailings Piles 1, 2 and 3) directly south of and adjacent to Railroad Creek. Howe Sound closed the mine in 1957. In 1961, the property was transferred to Holden Village, Inc. (Holden Village), a not-for-profit corporation that maintains a year-round community and operates an interdenominational religious retreat in the former miners’ town. With the exception of the patented private land, the remainder of the Site is on National Forest lands and is administered by the U.S. Forest Service. The mine is remote. It is only accessible by boat or float plane from Chelan, Washington, up Lake Chelan to Lucerne, nearly 40 km. Vehicle access from Lucerne to the mine is provided through a 17.5-km-long winding gravel road that climbs 640 meters in elevation. The general site features are shown in Figure 2. Physical setting The Holden Mine is located on the eastern slopes of the Cascade Mountain Range at an elevation between 975 and 1,050 m above mean sea level. Holden Mine was developed adjacent to Railroad Creek, which lies in a glacial U-shaped valley carved into the igneous and metamorphic bedrock with steep-sided slopes (Figure 2)."

Jan 1, 2017

By Roger Escoda Estelrich, Joan Carles Casado Ortega, Mitchell Gerdau, Jose Raul Martinez, Jeb Pittsinger, Frank Perrone

The existing Chesapeake Bay Bridge-Tunnel complex is being expanded to include the Parallel Thimble Shoal Tunnel. This will be a subaqueous bored crossing between two islands constructed for the original 1960s immersed-tube tunnel. Jet grouting was employed by the Chesapeake Tunnel Joint Venture (CTJV) to provide watertight base plugs, launch and retrieval blocks for the tunnel boring machine (TBM), a TBM canopy to limit ground movement, and a retaining wall to enable off-island excavation: all within hydraulically placed sands. This paper will review the design and construction challenges, including soil permeability and recharge, grout communication, installed grout strengths, and remediation requirements.

Jun 23, 2024

By Ryan C. Linthicum

A system of steel sheeting and multiple levels of high capacity double corrosion protected soil anchors were used to restrain a major slope failure that occurred at the base of the Watchung Mountains mid-way through construction of a 650,000 SF retail center along Route 22 in Watchung, New Jersey. The implementation of a design-build earth retaining structure was necessary to stabilize and repair the disturbed mountainside in a timely fashion to permit completion of the retail center on a fast track schedule. The tied back steel sheetpile wall was approximately 2,000 feet long and varied in height from 12 to 25 feet. The hillside extended approximately 350 feet above and 600 feet beyond the wall with the main failure scarp extending 50 feet above and 90 feet beyond. The wall was constructed in a top-down manner and required the installation of 475 anchors to resist loads of up to 70 kips/ft produced by the creeping hillside and groundwater flows from both a series of springs and steady state seepage through an inclined zone of fine sand. Incorporation of a unique tie point connection eliminated the need for a waler, facilitating and simplifying modifications to anchor locations based on anchor load test results and conditions encountered during construction. Post grouting also proved to be an essential element in the successful construction. This paper presents the design and the construction methods used to restrain the significant earth lateral loads produced by a slope failure using steel sheeting tied back with high capacity soil anchors with anchor loads distributed to the sheeting through a unique tie point connection on a fast track schedule. Installation techniques, testing programs, and construction quality control are also discussed.

Jan 1, 2003

By Sam Kangwa, Thomson Sinkala

Th e re are three basic types of hole deviations in long hole d ri l l i n g , n a m e l y collar i n g , alignment and tr a j e c t o r y dev i a t i o n s . In mining, the accur a cy in drilling has a significant effect on the effi c a c y and economy of mining oper a t i o n s . This ar t i cl e d e s c ribes the types, s o u r ces and effects of hole deviations in mining oper a t i o n s . The art i cle further demonstrates the economic consequences due to hole dev i a t i o n s .

Jan 1, 2004

By Tyler Acorn, Paul Worsey, Nathan Rouse

The effect of the hole diameter on vibration attenuation has not been incorporated in most vibration models in the blasting industry. In current vibration models, the charge weight and the distance from the blast are the two primary variables that are addressed. Charge weight is a function of explosive density, charge length, and charge diameter. This geometry-weight can complicate the isolation of the charge diameter variable.

Jan 1, 2013

By M Wimmer

LKAB operates two underground iron ore mines located in the northern part of Sweden, both using sublevel caving (SLC) as the mining method. Knowledge of the mechanisms of gravity flow is important since it affects both ore recovery and waste dilution. This paper describes results from a large-scale field test carried out at the Kiruna mine with a focus on gravity flow. It is part of Work Package 2 in the I2Mine project financed by the EU. A total of ten rings were blasted. Smart Markers based on radio frequency identification technology were used to monitor the gravity flow. An accurate delineation of the isolated extraction zone requires reliable detection of all recovered Smart Markers and precise knowledge of the 3D position of the markers within the burden. It was therefore necessary to carry out borehole deviation measurements (collar, alignment and trajectory). The blast performance was monitored by high-speed filming, near-field vibration monitoring and velocity of detonation measurements. Three-dimensional stereo images were taken from the drawpoint and the loaded bucket after each mucking cycle. Based upon that, fragmentation was assessed both in 2D and 3D. Furthermore, volumetric differences were determined at the drawpoint, which reflects the mobility of loaded material. For draw control, the Fe content is estimated by measuring weight and assuming a full bucket. The measured volume of rock in each bucket further improves this estimate. Possible flow disturbances occurring at the drawpoint were revealed by video recording. Two-dimensional laser scanning was carried out during mucking to track the position of the bucket and estimate the position and slope of the muck pile.The results from this test clearly show that the gravity flow in the large-scale sublevel cave in Kiruna mine is often of disturbed character. Standard draw occurred only in three rings and shallow draw in the remaining seven rings. In five cases, shallow draw developed towards standard draw, but occurred at rather late stages during extraction (70–125 per cent). The maximum width of the draw varied between 10 m and 13 m except for one ring (6 m). The draw reaches the cave rather early (5–25 per cent extraction) in shallow draw situations and much later (about 50 per cent) during standard draw. Waste originates from above in most cases, while more significant portions often occur at about 20–45 per cent extraction.All the results from this extensive field test are not yet fully analysed, and further field tests are planned. A more detailed insight into gravity flow in large-scale SLC and possible influence by drilling, blasting and the mucking procedure is expected in the future.CITATION:Nordqvist, A and Wimmer, M, 2016. Holistic approach to study gravity flow at the Kiruna sublevel caving mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 401–414 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Rio Tinto Iron Ore (RTIO) manages eleven mines in the Pilbara region, Western Australia. Three of these mines have previously or are currently mining black shale that contains varying amounts of pyrite. Several new deposits currently being evaluated and existing mines that may progress below water table in the future, will also encounter this waste material. The black shale presents not just an acid rock drainage risk but also a spontaneous combustion risk. This paper presents the black shale management strategy and provides an overview of the relevant activities undertaken by RTIO. The strategy can be divided into two components which firstly involve defining the risk and secondly involve managing the risk. The mineral waste management plan is used to identify specific mineral waste hazards by:geochemical characterisation of waste material,undertaking mine site specific risk assessments,characterising the receiving environment,identifying sulfidic boundaries in geological and mining models,quantifying the amount of sulfidic material in medium and long-term mine plans, anddesigning and sequencing black shale waste dumps. Once a mine exposes black shale the Spontaneous Combustion and Acid Rock Drainage management plan is used and the major activities are: regular site meetings with a representative from every group that works with black shale;compliance with safe working procedures for site specific and detailed activities;regular training;the use of specific explosives to prevent premature detonation;ongoing geochemical characterisation;acid water management, monitoring and analysis;regular internal and external auditing of procedures and practices; andclosure planning assessments and preparations (ie cover trials, geochemical void modelling, geochemical waste dump modelling). The success of this holistic strategy is evident by the awareness of personnel within the business, thorough understanding of the geochemistry and by undertaking proactive management of black shale during mining. The strategy and management plans adopted by Rio Tinto Iron Ore have activities that other mine sites with potentially acid forming material may like to consider implementing.

Jan 1, 2009

By L. Kulik, J. den Drijver

Rhenish lignite will continue to play an indispensible role in the energy mix of the German Federal Republic for a long time to come. The use of lignite for electricity generation, upgrading and, if necessary, as a raw material is geared to the long term. The holistic management of opencast mines underpinned by approval law in the long term and a stronger focus on man, the environment and nature contribute to the acceptance of the mines by the local population. The same is true of state-of-the-art lignite uses: as regards their operational flexibility, lignite-fired power plants are ideal partners for the expansion of renewables. It is along these lines that RWE is continuing its power plant renewal programme as planned. With a view to that which will be conceivable the day after tomorrow, RWE is researching future technologies today in order to meet objectives such as security of supply, profitability and environmental compatibility to the same extent in the long term. Another important contribution to acceptance is public transparency and communications as means to support approval procedures and the implementation of measures in all areas related to lignite mining and utilization.

Jan 1, 2011

By Christian Leble, Dr. -Ing. Jakob Vogelsang, Dr. -Ing. Oksana Solt, Dipl. -Ing. Joachim Meier, Dr. -Ing. Wolfgang Orth

In the course of closing the gap between the Brandenburg Gate and Alexanderplatz, the Museum Island station was built by Implenia Construction GmbH. The tunneling for the platform hall took place on a length of about 106 m (347 ft) under the protection of a major ground freezing measure and crossed the Spree canal as well as the listed castle bridge. The approximately 20,000 m³ (4.54 E+06 US gal dry) frozen mass lay mainly in the Berlin sands. In order to ensure safe tunnelling and to protect the adjacent buildings, the planners had defined requirements for the mean freezing temperature and thickness of the frozen mass. For a reliable conclusion on the dimensions of the frozen mass, we used innovative temperature sensors as well as the new, web-based 3D measurement visualization and the associated site-specific evaluation software. The largely automated evaluation enabled a quick and reproducible determination of the temperature distribution in the frozen soil and its thickness in the relevant cross-sectional areas. The measurements were validated by thermal calculations using the Finite-Element-Method. Thus, an objective and clear assessment basis was available to ensure rapid coordination between stakeholders. The evaluations provide new insights into the temperature influences from tunneling, the application of shotcrete and the concreting of the inner shell. The newly implemented active thawing system is also an interesting innovation.

May 1, 2022