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By Ian Sheppard, Kugan Kuganathan

The Mount Isa Rocky Paste Fill (RPF) was one of the five fill options investigated for the Enterprise Mine filling between June 1996 and September 1996. Co-disposal of deslimed cemented tailings (CHF) and suitably graded rockfill (RF) in certain ratios produced the rocky paste fill. The RPF behaved like a cohesive paste with very high proportion of rockfill in the mix. Several large-scale mixing trials and drop tests proved that the rocky pastefill results in a homogeneous fill mass after placement. Segregation of RF was a common problem with MIM's traditional cemented rock fill (CRF), which is a combination of CHF and RF. The segregation was eliminated and a non-segregating paste like fill was created by optimising the particle size distribution of RF, and combining the RF and the CHF in optimum ratios. In rocky pastefill, the excess water in the cemented deslimed tailings slurry is taken up by the rockfill as the surface moisture on the rockfill particles and also as pore water between the particles. This results in thickening of the CHF, and the resultant mix is a non-segregating cohesive paste, which can easily spread to any horizontal distance inside a stope at a very low surface angle. The rocky pastefill releases no free water and relatively more pervious than the standard CHF due to rockfill component. With an average cement addition of 1.5 to 2% the rocky pastefill can develop higher strengths over 1Mpa. The rocky paste fill is applicable in many situations and can accommodate a variety of coarser materials that would be available in different mine sites. This paper present the research work and the experience associated with the rocky paste fill, and gives clear design principles for any potential users.

Jan 1, 2001

By Walter R. Curtner

Many, if not most, of today's pollution liability claims are related to events ("occurrences") that happened in the past. This fact creates an opportunity to obtain a large amount of insurance coverage at essentially no cost. Furthermore, in many cases, this insurance coverage is readily available. Scenario #1 For some 15 years, an underground gas tank has had a slow leak. The leak has now been discovered because the gas has contaminated nearby wells. As a result, an expensive $1 million cleanup is required. In addition, a liability suit has been filed for damages due to the contamination of nearby wells. Consequently, legal expenses are being incurred. Are all of these actual and potential costs insured? Obviously, if you have a pollution liability policy in place, the above costs will probably be insured. I say probably because business liability policies are not uniform. But, what if you don't have a pollution liability policy and what if your current general liability policy excludes all pollution liability (as most of them do today)? Under these circumstances, it first appears there is no insurance for this $1 million cleanup and liability suit. But this is probably not the case. You may well have insurance coverage, and you may well have much more insurance coverage than you ever expected. And, the insurance that I'm referring to is already in place. You simply need to find it and learn how to use this insurance - I'm referring to your old policies. In many cases, old liability insurance policies provide coverage for claims made today, because these policies were written on an "occurrence" basis of coverage. In fact, most still are written this way. This means that the insurance policy covers bodily injury or property damage liabilities (as defined in the policy) arising out of' "occurrences" or accidents that happen during the policy period regardless of' when the claim for damages is made. Therefore, for insurance purposes, the key question is: when did the "occurrence" take place? If someone falls and breaks a leg, that is clearly an "occurrence." The broken leg occurrence is, therefore, insured by the liability policy that was in existence at the time of the fall - regardless of when the claim or suit is filed, if ever. However, the answer to this question is seldom an easy one when you are looking at a pollution claim. In our scenario, the tank had a slow leak over 15 years, but property damage was not discovered until now. The question of when the "occurrence" (as defined in the insurance policy) took place has been litigated and continues to be litigated in many courts across the country. But, most often the answer has been that, for insurance purposes, the "occurrence" is the entire period that the tank was leaking (15 years), even though the contamination to the water was not discovered until 1987. This means that the person or company that is insured can potentially use all of its general liability policies (if they are "occurrence" policies, and most were), which were purchased during the 15 years from 1972 until 1987. And, these policies will potentially insure all of the claims and related exposures that arise out of this leaky underground gas tank. Scenario #2 In our first scenario, the claims and expenses were insured by past general liability policies because the claims arose out of events in the past, which, in turn, caused damage. Let's look at another example. In this scenario, Company XYZ has received a request to help clean up a landfill site because 10 years ago, XYZ dumped some toxic substances at the site, which was totally legal at the time. XYZ has not dumped anything at the site since this time. Nevertheless, XYZ is now being required to contribute $2 million to the cleanup of this site. In this scenario, if you had purchased "occurrence" general liability policies 10 years ago, these 1977 policies would (potentially) apply to the current $2 million cleanup claim. And, the reason is that the "occurrence" leading to the 1987 claim took place in 1977.

Jan 10, 1987

By M. Birdsell

"Sustainable long-term restoration requires adequate planning and preparation, implementation, and measurement goals to monitor success associated with restoring sites to pre-disturbance levels of ecological health. The Buckhorn Mountain Mine riparian habitat restoration project has been a multi-year endeavor with a variety of restoration techniques implemented by Kinross Gold/Crown Resources Corporation. INTRODUCTION The Buckhorn Mountain Mine procured mitigation lands during the permitting process to be set aside for long-term restoration. A portion of this mitigation land included three aquatic habitat mitigation parcels; a spring and wetland complex and two stream and riparian corridors. These properties were historically used for agriculture purposes and livestock grazing. During initial permitting, habitat monitoring and mitigation plans were created to help guide restoration, and provide measures for success. Various techniques and adaptations have been implemented on the properties since 2007, and continued efforts are being implemented annually to ensure the long-term success of the project. Field measurements are collected annually to ensure mitigation objectives are being met, and provide opportunity to modify restoration efforts when necessary. MATERIALS/METHODS Restoration efforts have included implementation of several methods including livestock exclusion, treatment of state and locally listed noxious weed species, installation of regionally sourced riparian plant species and local stock willow cuttings. Annual mechanical and herbicide treatments for noxious weeds have been conducted annually. Efforts to control reed canarygrass (Phalaris arundinacea) have been implemented since 2013; methods include mechanical and herbicide treatments. A combination of methods has been employed to help aid restoration of native species within the riparian corridor, and increase survival of planted species, including weed matting and browse barriers to aid riparian planting success. Instream planting of local stock willow have also been employed to increase stream vegetative cover and provide long-term bank stabilization. Most recently, a perched culvert near one of the properties has been replaced with an aquatic life passable culvert designed to aid in the upstream migration of fish species into the stream system. Efforts to provide increased fisheries into upstream portions of the system and aid in restoration of stream bed and bank have been employed to increase the ecological value downstream of the replacement. In addition to efforts completed by the client to provide restoration efforts, a local non-profit organization, in conjunction with the client, installed beaver dam analogues (BDAs) in the fall of 2014. These structures are intended to raise water levels along stretches of incised channel in an attempt to flood historic off-channel floodplain"

Jan 1, 2016

By Dominic Parmantier, Jason Page

"In the past, the designers of DSM have analyzed various failure modes and then specified a minimum unconfined compressive strength (UCS) for the soil-cement. The specified minimum UCS reflected the compressive stress in the soil-cement under design loads and an appropriate factor of safety. With the increased use of finite element analysis for the design of DSM applications where allowable strain as well as stress are considered, there is a growing trend for designers to specify a modulus and occasionally a tensile strength for the soil-cement in addition to the UCS. This paper compares the relationship of modulus and tensile strength to UCS for soil-cement from a recent DSM project with unique testing requirements. These results are compared to published data. The case is made that designers should utilize published relationships to characterize the required strength and stiffness by a single acceptance criterion: UCS.INTRODUCTIONAs the use of DSM has increased in popularity so has the use of service state deformation analysis in lieu of more traditional failure mode analysis. Most DSM designers are interested in the appropriate modulus values and occasionally tensile strength values of soil-cement as well as simply the unconfined compressive strength (UCS) of soil-cement.Although there are numerous published correlations between the UCS, tensile strength and modulus of soil-cement, some DSM project specifications are produced which have acceptance values for tensile strength, modulus, and UCS. If this specification of multiple strength properties is consistent with the nature of soil-cement, then there is really no harm except for the expenditure of client money on unnecessary testing. If however the multiple strength properties specified are inconsistent with the material properties of soil-cement, then the specifications can create the expectation that the DSM contractor can somehow create a custom soil-cement with tensile strengths and modulus characteristics which are unachievable.This paper presents a brief summary of a project in Burnaby, B.C. which specified minimum values for the tensile strength, modulus, and UCS of the soil-cement. A comparison of those test results to published correlations between the UCS and the tensile strength is presented. Additionally, a comparison of modulus derived from two different methods of testing is presented along with a comparison to published correlations between UCS and modulus for soil-cement."

Jan 1, 2015

By Lloyd Litwin

The ARTA 2008 Project (Alpha Ridge Test of Appurtenance) was a Canadian Government sponsored deep water seismic survey carried out on the high arctic permanent polar ice cap. This Geological Survey of Canada operation was the second seismic research project in the high Arctic and was monitored by the Danish Government. Utilizing 100% air support from Eureka and then helicopters from an ice based tent camp north of Ellesmere Island, the five week study was accomplished in the early spring just after the sun returned to the far north.

Jan 1, 2011

By Manabu lshimaru

Solid-liquid interfaces as well as defect formation processes during crystallization of melted silicon (Si) have been examined by using molecular-dynamics (MD) simulations. The ordinary Langevin equation employing the Tersoff interatomic potential was used for the calculation of the atomic trajectories. A solid-melt interface has a tendency to form {]] I} microfacets during the crystal growth in the [001] direction, while it is essentially flat during the (Ill) crystallization. Because of the difference of the interfacial structures, the structures of grown-in defects and defect evolution depend strongly on the growth direction. We discuss defect structures and their formation processes within the context of our results as well as previous experimental observations.

Jan 1, 2001

By C. L. Popp

The scope is to address issues confronted by parties in the mining industry such as: Mine planners, survey and engineering departments, field teams and subcontractors. Describing approaches and best practices for assembling a project team to identify and create modeling requirements and to implement beneficial results. 3D Machine Control and Guidance tools continue to reduce project risk and attract quality resources with skill sets new to the earthmoving industry. These tools increase production, reduce rework and help with government permitting.

May 1, 2013

By Paolo M. Brion, Z. Bade Sozer

"The Bypass Tunnel has high head conditions ranging from a minimum of 600 feet (183 m) under the Hudson River to a maximum of 875 feet (267 m) on the west side. The ground cover ranges from 425 feet to 900 feet (130 to 274 m). A two-pass lining is designed for the Bypass Tunnel. The bolted, gasketed precast segments carry the temporary hydrostatic and permanent ground loads. After the tunnel is put into service, the design assumes that the final lining, which varies from reinforced concrete to reinforced concrete with steel interliner, will carry the permanent hydrostatic loads. The design head for the segments is assumed at 775 feet (236 m), and the internal operating pressure head is around 1,200 feet (366 m). This paper discusses the design hydrostatic head and different load conditions considered for the segments, the load sharing between the segments and final lining, and the means employed to control water and hydrostatic pressure. PROJECT BACKGROUND The Rondout-West Branch Tunnel (RWBT), a segment of the Delaware Aqueduct, was built from 1937 to 1944 and provides about 50% of New York City’s total water supply. Monitoring and tunnel operations have shown that the RWBT is leaking up to 35 million gallons per day (MGD) (132.5 million L/day). In particular, two locations have been identified as areas of concern: Roseton and Wawarsing, as shown in Figure 1. The Wawarsing reach of the aqueduct will be repaired with an extensive grouting program when the RWBT is unwatered. However, because of the extensive nature of the leakage in the Roseton area, a Bypass Tunnel will be constructed to divert the flow around this area."

Jan 1, 2016

By S Talu, E Savage, S Howe

Major falls of ground, strainbursts, airblast and mudrush events are the major hazards in block caving environments, resulting in both safety and financial consequences and losses. Rio Tinto mines have developed strategies to reduce the likelihood of these events occurring. However, until recently, there have been no tools available to monitor and manage these hazards in real time.Mira Geoscience and Rio Tinto have collaborated to develop real-time geohazmaps to monitor and manage major cave hazards. These geohazmaps are used by mine planners to integrate multiple hazard parameters that contribute to form a combined hazard rating.The benefits of implementing geohazmaps include safety and cost improvements through the early identification of potential locations for major events. These cost savings are realised in the design phase, where development and critical infrastructure is located in areas of lower hazard rating. Additional improvements can be achieved by taking the hazard level into consideration when planning the production and development schedules and ground support design.CITATION:Talu, S, Savage, E and Howe, S, 2016. Geohazmap implementation in block cave mines, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 817–822 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Selective Flocculation process development generally involves single mineral flocculation tests to identify the appropriate polymer and experimental conditions for achieving the desired selectivity. Invariably the selectivity predicted on the basis of such tests is not realized when mixed mineral tests are conducted. A systematic experimental investigation revealed that adsorption of the polymer on various substrates is critical to selecting the suitable flocculent. Simultaneously, a mathematical model was developed to predict the overall process efficiency with a given polymer. In this paper, results of these efforts to scientifically design a suitable selective flocculation process are presented.

Jan 1, 1991

By Robert H. Raring

Viewed abstractly, a mill may be defined as a mineral processing facility located somewhere between the mine and the tailings storage area, Just how mining operations and the demands of tailings storage affect mill design is, the subject of this paper. At the outset, it will be readily acknowledged that no two installations can, or ever will be the same. At one extreme is the bucket line dredge where the distance between the ?mine? and the tailings area is measured in terms of tens of feet. At the other extreme, the large open pit copper mines are frequently spread across twenty, miles or so of countryside with the ore moving to the mill, as exemplified by the operations at Bingham Canyon, Ray, or Ruth - the "upstream" counterparts of Garfield, Hayden and McGill. In each of these cases, mill location was largely determined by requirements for tailings storage and/or water supply.

Jan 1, 1961

By Y. Hayashi, A. Fuwa

To analyze zinc vaporization kinetics of zinc smelting slag in the ISP furnace, reduction reaction rate of zinc oxide from ZnO-FeOx-CaO-SiO2 slag system with CO-CO2-Ar gas mixtures has been measured by a therm o-gravim etric apparatus at various ZnO content, Pco, and temperature. The reduction rate was measured under a chemical reaction control in the initial three minutes where surface zinc content can be assumed constant. Through the reaction rate dependency analysis on ZnO contents, Pco and temperature, discussion has been made on its reaction mechanistic information in terms of rate coefficient, adsorption/desorption mechanism and activation energy.

Jan 1, 2008

By Laura A. Sanders

Mineral scale formation is prevalent in numerous mining operations. Such scale formation can occur in the direct-contact heat exchangers ahead of an autoclave. In these heat exchangers, the incoming slurry comes into contact with steam in a stage-wise fashion, which is re-circulated from the downstream flash vessels to heat the slurry in stages ahead of the autoclave. Calcium sulfate scaling causes severe problems in mining operations where increased temperatures are involved due to rising temperatures promoting calcium sulfate scaling through a decreasing solubility. In a number of these operations, the scale formation can occur in the presence of mineral solids, where fine-grained charged particles are at concentrations in excess of 35%. Scale prevention is not difficult in standard aqueous systems; however, the presence of solids leads to significant deficiencies in the prevention of scale due to the adsorption of the polymer onto the charge solids instead of the polymer interaction with the scale. Therefore, a technical solution to prevent mineral scale build up occurring in presence of pulp slurry in mining operations is needed. Several novel antiscalant technologies were developed and evaluated which provided a substantial improvement in the scale prevention in such systems.

May 1, 2013

By Adrian Dance

Newmont Ghana Gold Limited?s Ahafo operation have been working with Metso Process Technology & Innovation (PTI) since early 2009 to increase mill throughput from a combination of controlled blasting practices and optimised primary crusher and grinding circuit conditions. For such Mineto- Mill projects, PTI?s methodology is termed Process Integration & Optimisation (PIO). Ahafo operate a SAG mill, ball mill and pebble crusher (SABC) circuit that processes a range of primary ore of varying hardness from different pits which is blended with soft oxide material. The PTI study focussed on ball mill limited material from the Apensu open pit. Following a benchmarking study of all blasting, crushing and grinding practices in January 2009, PTI recommended changes in both blasting and crushing conditions in order to generate a finer feed size to the SAG mill. Additional operating changes in the grinding circuit were recommended. A series of trials were conducted in November 2009 where three blasts were fired using a different blast design (hole diameter and explosive type) in the same area of the Apensu pit as the benchmarked material in January 2009. Top and bottom benches (or flitches) from each blast were sent exclusively to the grinding circuit and the material was tracked using PTI?s SmartTag? system. The results from the six trials showed a significant increase in primary ore throughput at a reduced blend of oxide material. Ahafo have since standardised on these modified blasting conditions for all Apensu ore zones and have been able to sustain higher throughput compared to historical performance on similar material. This paper summarises the phases of the PIO project, the changes made in operating practices and the outcomes of the blasting trials that validated the predicted increase in mill throughput.

Jan 1, 2012

By Harry Verakis, Thomas Lobb

Blasting accident data over a 30-year period (1980-2010) are summarized and presented for all types of surface and underground mining operations in the USA. The historical record of injuries from blasting accidents in all types of mines continues to show a significant decline. The overall decline in mine blasting injuries in the U.S.A. has resulted from advancements in blasting technology, training and improvements in blasting products and blasting processes. Some of the technology advancements such as safer blasting agents and computerized bulk vehicle loading, electronic detonators and remote operated blasting systems, and computerized blast design have and continue to significantly contribute to improvements in the historical blasting safety record. Also, the progress of significantly improving the safety of mine blasting has resulted from the combined efforts of miners, mine companies and operators, miners, unions, explosive and blasting product manufacturers, associations such as the International Society of Explosives Engineers and the Institute of Makers of Explosives and various government agencies.

Jan 1, 2012

By B T. Lusk, John J. Silva Castro

The signature hole method uses a convolution operation to predict the waveform of a production blast based on the record of a waveform produced by a single blast hole. Convolution is a mathematical operation on two functions, (generally the product) to produce a third one. Recent research communication and publications highlight a lack of discussion in the literature about the available methodologies to calculate the convolution for blast vibration prediction. The goal of this paper is to discuss and present in detail for students in ground vibrations from blasting, several techniques to calculate the convolution between signals when the signature hole method is used. Convolution is a straightforward operation when signals produced by each hole are assumed the same, however; variations in the signals from each hole in a production blast require a more complex convolution operation. A graphical procedure is shown in this paper to solve a convolution when signals vary hole-to-hole (as expected in a mining production blast). The graphical methodology was tested using a recorded blast event and the results were compared to the regular mathematical procedure (convolution) and the results from a commercial software used in the mining industry. Results show that the graphical procedure is in agreement with the results from the other two.

Jan 1, 2014

By M J. Noy

The automated measurement of rock fragmentation particle size distribution in the muck during muck excavation has been developing over the last 16 years. The introduction of stereo camera imaging of the muck has provided improved automated particle segmentation for image-based measurement algorithms. Recently, a new vision system processing algorithm has been developed. The inclusion of 2D texture in the analysis has provided a significant improvement in the definition of the finer size fractions, which has resulted in the automated analysis no longer requiring calibration.The previous stereo vision system algorithm required analysis calibration to account for poor ‘small particle’ definition in the 3D surface profile. This was because of the depth perception limitations of the stereo camera system at greater than 8 m. The new algorithm has been implemented on a number of shovel-installed vision systems, and the algorithm’s performance in automated analysis has been assessed against a diligent manual analysis of the same fragmentation images. The new algorithm provides improved distribution resolution and accuracy.CITATION:Noy, M J, 2015. Evaluation of a new vision system algorithm for automated fragmentation measurement from a shovel, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 721–726 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Andrew Moore

It has long been common practice to conduct drilling and blasting operations at surface quarries in the Midwest in close proximity to near-vertical highwalls. The main reasons for such an approach, and the limited use of adequate safety controls, can be associated with higher costs, operational constraints, lithological requirements, property boundary restrictions, inadequate quarry planning, or a lack of understanding of highwall risks. Working in proximity to highwalls, without effective controls, exposes personnel and equipment to increased risk of incidents. In recent history, there have been isolated incidents involving equipment damage, or personnel injury/fatality around the United States. However, the Midwest market has largely escaped the effects of such incidents, even though the exposure rate is high. Awareness about this matter greatly increased on January 19th, 2021, when a significant incident occurred at a quarry near Green Bay, Wisconsin. As a crew was loading a typical blast near a highwall, a ground fall occurred, and multiple rock fragments struck a laborer working on the bench below. This individual sustained significant and life-altering injuries.

Feb 6, 2023

By Maxim Martel, Karolan Tremblay

Westwood Mine has experienced several episodes of increased seismic activity. While current geotechnical characterizations such as RMR, GSI, and Q' index can identify the general rock quality and zones at risk of convergence, they fail in identifying zones at risk of seismic activity. Previous research at Westwood Mine has shown a correlation between seismicity and areas with strong rheology contrasts. To characterize this contrast, 300 UCS tests were analyzed with their associated geochemical data, and statistical analysis and regression were performed using IOGAS software to establish a relationship between resistance and geochemistry. UCS-generated data with XRF results were transferred to Leapfrog Geo to create a block model of intact rock strength. This block model dataset was used to perform a competency contrast block model, and back-analysis of specific seismic sectors at Westwood Mine were conducted to validate the model. The purpose is to develop an established geomechanical tool capable in identifying areas with greater seismic risk associated to a change in the rock strength characteristics. By identifying those areas, mitigation measures can be implemented to minimize impact of seismicity on the operation.

Jan 1, 2023

By Aditya Ayithi, William G. Ryan, Dean Herbst

"For rock socketed drilled shafts, it is a common practice not to include the frictional resistance of overburden soils into the nominal capacity estimation. The primary reason often being cited is “overburden soils resistance is negligible compared to that of rock socket resistance.” However, in certain geological conditions, where the rock layer is located at greater depths, friction resistance from overburden layers can be significant. In addition, at such great depths, shaft drilling becomes very complicated and expensive. In these situations, considering the resistance of the overburden layers can be an economic alternative.This paper presents a case study of an Osterberg cell (O-cell) load test conducted on a 161.8 feet long and 78-inch diameter instrumented test shaft. Based on initial designs, a 72-inch diameter rock socket of lengths 23 and 26 feet was required to provide a LRFD factored friction resistance of 3,200 kips. The load test results revealed that the material in the 72-inch diameter socket does not represent a true rock. However, the test results also proved that the factored friction resistance of overburden layers is greater than the required design resistance. Based on the load test results, it was decided to allow the overburden soils frictional resistance to be considered in the shaft design, resulting in significant economic savings.INTRODUCTIONRock socketed drill shaft design guidelines of various State Department of Transportation (DOTs) agencies allow friction and/or end bearing resistance of only the rock socket portion into the design capacity estimation. It is typical to neglect the frictional resistance of overburden soils. However, in certain geological conditions where the rock layer is at greater depths, friction resistance of the overburden soils can be significant. In this case the friction resistance of overburden soils was verified via the specified instrumented O-cell test program and then used as part of the design capacity.PROJECT DESCRIPTIONAs part of I-29 improvement project, Iowa Department of Transportation (Iowa DOT) planned to replace the dual four lane bridges that cross the Floyd River in Sioux City, Iowa with dual six lane bridges (Fig. 1). Expected benefits from this improvement include improved safety, traffic operations and roadway infrastructure conditions.BRIDGE SUBSTRUCTUREThe project consists of two individual bridges; a new south bound bridge and a new north bound bridge. The south bound bridge is 646-ft long and the north bound bridge is 644-ft long. Both are six-span, pretensioned and pre-stressed concrete beam bridges of varying width. Bridge foundations were designed such that the abutments of both bridges will be supported on driven steel piles and the bridge piers will be on drilled shaft foundations."

Jan 1, 2016