Global Trends in Mining & Metals 2019:
Phil Hopwood, Global Leader - Mining, Deloitte
Phil will cover the major global Mining & Metals trends in 2019. For the past 11 years Deloitte has published its global trends report focusing on the drivers of change in the industry. Areas that will be discussed will include: the impact of digital technology, attracting talent, the need for the industry to show its value to stakeholders beyond simply complying with regulatory requirements, the impact of electric vehicles, and what is the role of strategy in Mining & Metals companies in 2019. As well as this Phil will cover his views on where Mining & Metals is right now in the Commodity cycle.
Phil Hopwood leads the Deloitte Global Mining & Metals team. With over 30 years of professional experience he has worked in the Mining & Metals industry for over 21 years with clients in Australia, China, Singapore, South America, Canada and US. Key areas of focus include M&A advisory, business transformation, and value extraction from technology. Phil has lived and worked in Canada, UK, and Australia, and is currently based in Toronto. Phil regularly speaks at mining conferences globally on trends in mining and leads the annual production of Tracking the Trends in Mining, Deloitte’s premier mining thought leadership report, now in its 11th year of publication.
Allyz Kramer, SEH
Recent EPA Policy Changes and Your Mining Facility: Overview, Opportunities, Risks, and Examples
10:45 am | Phil Fish and Todd Fasking, Barr Engineering Co., Minneapolis, MN
In a series of recent and pending guidance documents and rulemaking, the EPA is changing how several key federal requirements apply to mining facilities. Important changes to date include project emissions accounting for ”Step 1” decreases, the reversal of the ”once in, always in” policy for federal MACT changes, project aggregation, and revising how stationary sources are defined. Upcoming changes of significance are expected to include further definition of ambient air and clarifications regarding its routine maintenance exclusion. The presentation will provide an overview of the changes, the benefits and risks, and practical examples when these changes are important.
Social License to Operate: Trendy jargon, what does it actually mean?
11:15 am | LaTisha Gietzen, PolyMet Mining, Inc., Hoyt Lakes, MN
Social License to Operate: companies are using all kinds of trendy jargon, but what does is actually mean? Surprisingly, the answer is not straightforward or uniform across companies and organizations. Who grants the license or takes it way? PolyMet prefers the terms Corporate Social Responsibility and Mining Responsibly. Creating accountability requires defining clear expectations to drive trust through operational performance, transparency and stakeholder engagement. PolyMet will review its approach to stakeholders and how it employs these attributes to earn and keep community trust.
How to Deliver a Positive Community Experience
11:45 am | Susan Courter, Courter Resource Group, Jim Falls, WI
Finding, starting and running a new mine is more difficult and expensive than ever before. Besides spiraling costs due to lower grades and expanded government intervention, communities do not understand or trust mining. This has led to lower returns for companies and their investors, and reduced society’s access to affordable, quality resources. Investor returns are proportional to community trust, and this presentation will focus on three steps leading companies take to revitalize their social license to operate by (1) making mining project information accessible, (2) cultivating healthy partnerships with people of all kinds and backgrounds, and (3) co-innovating to minimize impacts and shape a positive future together.
Relocating a Community Amenity for Mine Progression — Hibbing Mine View Planning, Removal, Relocation, and Grand Re-opening – Hibbing, Minnesota
1:45 pm | Matt Bolf, SEH, Duluth, MN and Andrew Lucia, Lucito, Hibbing, MN
The rich history of Minnesota’s Mesabi Iron Range is told and retold through varied sources. But, for visitors to the Hibbing Taconite and Hull Rust Mahoning Mine View facility, a bird’s–eye view of the vast historic and present mining operations is worth a thousand words. When Hibbing Taconite Company announced that its ongoing progression of taconite mining would overtake the existing mine view overlook, consideration and collaboration with nearby community and Iron Range stakeholders was required to determine ways to relocate this treasured community park and visitor center. The City of Hibbing, Cleveland-Cliffs, Inc., Hibbing Taconite Co., and Minnesota’s Department of Iron Range Resources worked through varying elements of the relocation to ensure the park and visitor center would continue to provide the opportunities for its thousands of visitors each year. A primary goal was for this audience to gain knowledge of the rich mining history and vast geologic reserves of Northeast Minnesota in context of the region’s heritage. This is the “nuts and bolts” story of community leaders, industry, infrastructure engineers, and architectural visionaries collaborating to recreate the Mine View in Hibbing, Minnesota for generations to come.
The Minnesota Sulfate Rule to Protect Wild Rice – An Update in 2018
2:15 pm | Rachel Walker, Barr Engineering Co., Minneapolis, MN
In 2018, Minnesota’s Governor Mark Dayton requested, through executive order, the formation of a Task Force to discuss and address a state sulfate standard to protect wild rice. The Task Force was described as “a nonpartisan group of experts and key stakeholders who are committed to finding a compromise solution to wild rice restoration and protection in Minnesota.” Its members include representatives from Tribal Nations, industry, environmental advocacy groups, scientists, state government agencies, and other stakeholders. This discussion has relevance for mining in Minnesota today. With the introduction of proposals for new mining projects in northern Minnesota, concerns regarding potential impacts on important natural resources has emerged. Specifically, concerns regarding potential impacts to wild rice, a plant of significant cultural significance to Minnesota American Indian Tribes, have been expressed. We examine the history of the sulfate standard, some of the research undertaken over the last ten years, key scientific outcomes, and questions left unanswered. We also examine the status of some of the Task Force’s discussions as they relate to wild rice restoration and protection. Finally, we examine some of what has been unique about this case both in Minnesota’s and the U.S.’s environmental regulatory history.
Evan Johnson, Northeast Technical Services
Tailings as a Resource
10:45 am | Nils Stewart, Weir Minerals, Austin, TX
Globally mines use significant quantities of cementitious construction products for many applications from shotcrete, for support and stabilization, to concretes for roadways or civil structures both on surface and underground. Typically these cementitious products are manufactured from offsite components, mainly aggregates and cementitious powders (Portland cement, slag and fly ash). In some instances the mine site may produce its own aggregate from crushed and screened waste rock.
The use of these imported products represents a significant capital expenditure to any mine.
The development of metallurgical tailings based construction products, to replace conventional shotcrete, concrete, grouts and foamed products, offers benefits to underground mining operations by:
Reducing the cost of existing traditional aggregate based construction materials.
- Reducing the quantity of tailings to be stored in the tailings storage facility (TSF).
- Increasing the product performance over traditional aggregate based materials.
- Utilising the existing infrastructure where available to transport the tailings and additive components of the products underground.
- Reducing shaft or decline usage for transporting large quantities of pre-bagged shotcrete/concrete materials underground
This paper discusses studies undertaken to evaluate the use of metallurgical tailings from a number of mining operations globally as an aggregate replacement in cementitious construction and support products. In particular the use of tailings in shotcrete, concrete, grouts and foamed materials as well as the manufacturing process involved in delivering a tailings based civil product.
World Example of paste thickener technology benefits for iron tails and slimes
11:15 am | Jerold Johnson and Lee Webb, Westech Engineering, Salt Lake City, UT
Paste type thickeners have been in use for the past 20 years and iron mines have been one of the chief users. Non-Newtonian underflow provide benefits like, reducing water sent to the TSF by 30 to 50%, rapid drying producing a stable deposition is weeks, reduced failure risks, and increasing the life of the TSF. Surface stack cost saving are very significant when considering the whole tailings system. This presentation introduces some basic properties of Paste & Thickened Tails, P&TT, the design basis, and the benefits. Case studies of several iron installations (green and brown field) from around the world are provided.
Fundamentals of Tailings Liquefaction — What Owners and Operators Need to Know
11:45 am | Kurt Schimpke and IvÃ¡n Contreras, Barr Engineering Co., Minneapolis, MN
Tailings impoundment dams are frequently raised using the upstream construction method, in which the dam section, or a portion of it, is founded on soft tailings. The method offers economic benefits, but also presents risk associated with construction over soft tailings that may be susceptible to liquefaction. Liquefaction is a complex phenomenon characterized by a rapid decrease in shear strength, which is often so significant that tailings may temporarily assume the consistency of a thick liquid. If triggered, liquefaction may lead to impoundment dam failure and tailings release from the storage facility. Liquefaction can be triggered by a seismic event or vibration, but also by static mechanisms such as slope steepening, foundation overloading, changes in pore-water pressure, deformation, and/or dam overtopping. Appropriate tailings storage facility design must account for the possibility of tailings liquefaction. There are also operational best practices that can be employed to reduce risk associated with tailings liquefaction. This presentation will provide owners and operators key information necessary for safe operation of tailings storage facilities with respect to liquefaction.
Hibbing Taconite Co. Mixed in Place Seepage Cutoff Wall
1:45 pm | Christopher Winter, Hibbing Taconite Co., Hibbing, MN
Hibbing Taconite Company’s (HTC) Tailings Storage Facility (TSF) impounds tailings within earthen dams from a magnetite iron ore processing plant approximately five miles north of the City of Hibbing in St. Louis County, Minnesota. In 2017 HTC undertook the evaluation of potential seepage cutoff wall options. The evaluation required engineering and analysis of potential options to cutoff seepage in a portion of the system of dams at HTC. The engineering and analysis lead HTC to select the One Pass Trenching Method Technology for the construction of the seepage cutoff wall. This paper will explore the evaluation, design and construction of a 4,000 foot length by 80 foot depth by 3 foot width One Pass Trenching Method Soil-Bentonite Wall that functions as a seepage cutoff at Hibbing Taconite Company.
Seepage Control Cutoff in an Extreme Saline Environment
2:15 pm | Darla Erickson and Bethany Kelly, Barr Engineering Co., Minneapolis, MN
A trona mine in Wyoming stores tailings and water with high salt content, which results in seepage water with high salt concentrations. Existing instrumentation, subsurface investigations, and field observations identified a zone of fractured bedrock as the unit most susceptible to carrying significant seepage from the basin. To reduce the impact of salty water in groundwater downstream, site improvements included seepage cutoffs extending into more competent bedrock. This paper describes the site geology, subsurface characterization, selection and design of the seepage cutoff technology, QA/QC, construction, and monitoring of the cutoffs, which have effectively mitigated the seepage and environmental concerns.
Julie Lucas, Hibbing Taconite Co.
Assembling Minnesota: The Importance and Use of Robust Geologic Data Sets
10:45 am | Dean Peterson, NRRI, Duluth, MN
Since the 1880s, exploration and mining has revealed much of the geology of Minnesota and generated vast amounts of data. Although numerous scanned historic files are accessible online, a lot of these data still reside in analog archives. Great strides have been made digitizing historic data, though major gaps exist and standardization is by no means complete. Assembling Minnesota is a NRRI program creating a seamless and query-ready geological GIS compilation designed to: investigate mineral potential, inform environmental management, integrate geological data into other natural resource disciplines, anticipate emerging issues, and answer questions before they are asked.
Minnesota’s Trust Mineral Estates
11:15 am | Julie Marinucci, St. Louis County, Hibbing, MN and Aaron Vande, Minnesota School Trust Lands, St. Paul, MN
Minnesota has been funding schools, its universities and local units of government for over one hundred fifty years from its roughly 12 million acres of mineral assets. These 12 million acres are held in three main trusts that support of the University of Minnesota, Minnesota’s K-12 education system, and the counties and municipalities in which the minerals exist. During this session, you will learn about the history of how Minnesota came into ownership of these mineral estates, how mineral royalties help fund education as well as the potential for future mineral development of Minnesota’s vast mineral estate.
A Natural Resource Atlas for Northeastern Minnesota
11:45 am | Will Bartsch and Lucinda Johnson, Natural Resources Research Institute, Duluth, MN
The Natural Resources Research Institute and collaborators developed a comprehensive Natural Resource Atlas for Northeastern Minnesota. The publicly-accessible Atlas consists of a web-based Mapping Tool and multidisciplinary database that includes extensive geological and environmental data. The Mapping Tool functionality allows users to view spatial data, draw, measure, access attribute data, subset data, and summarize vector or raster data within natural, political, or user-defined boundaries. Potential uses for the Atlas include identifying natural resource economic development opportunities; identifying ecologically important areas; and providing scientifically sound data to industry, agencies, and the public.
County Land Use Planning – GIS Analysis of Mining Considerations
1:45 pm | David Yapel, St. Louis County, Duluth, MN
St. Louis County’s Comprehensive Land Use Plan establishes a long-term vision for managing land use where the county maintains zoning jurisdiction. The Plan’s overall intent is to support county goals and objectives for growth, development, conservation, and the well-being of the county’s residents. Given the county’s history of mining and its mineral potential, a primary objective of the Plan is to protect opportunities for future mining activity, while mitigating environmental hazards, and avoiding potential land use conflicts before they begin. This session will detail how the county’s Geographic Information System (GIS) was utilized to identify areas for mining-related considerations.
Management of Non-Ore Grade Rock at NorthMet
2:15 pm | Tamara Diedrich, MineraLogic LLC, Duluth, MN and Christie Kearney, PolyMet Mining, Inc., Hoyt Lakes, MN
Operations at the future NorthMet Mine will include blasting and removal of non-ore grade ("waste") rock in order to access the underlying ore for processing. This rock has been the focus of extensive geochemical testing over the last approximately 14 years to determine its weathering characteristics. In this presentation, we will describe how outcomes of the NorthMet geochemical characterization program have been used to form the design basis for waste rock management at the future mine. Elements of the waste rock management plan that will be discussed include the waste rock segregation criteria and schedule for subaqueous placement.
Corie Ekholm, Hibbing Taconite Co.
Operation of Primary Crushing - Are Autonomous Plants Possible?
10:45 am | Dusty Jacobsen and Dominic Fabbic, Metso, Waukesha, WI
Traditionally, the primary crushing section of a plant requires direct operation from a crew of two up to 10 personnel. Directing truck traffic, calling for truck dumps, adjusting crusher settings, adjusting feeder speeds, monitoring equipment and process information, etc etc require skilled operators to keep a plant operating with consistent and appropriate feed input. Significant advancements in monitoring technology and equipment automation has lessened the need for dedicated operator staff directly at the primary station. Primary crushing stations are currently being operated with minimal in-person support, and there is push within the industry to develop solutions where the transfer of mined ore through the primary crushing station requires no manpower at the site itself. The main requirements for autonomous operation are reliable and accurate sensors, robust automated controls, possibly remote monitor/operation-ability, and advanced controls of the crushing equipment. While the use of robotics and drones to completely eliminate human involvement, there has already been significant improvements in the other aspects. This paper discusses the advancements in remote and automatic operation of primary crushing stations and what the challenges have been (and will be).
Ball Mill Media Size Optimization Using a Torque Instrumented Pilot Mill
11:15 am | Kyle Bartholomew, Metcom Technologies Inc., Grand Rapids, MN and Doug Learmont, Midland Research LLC, Marble, MN
Grinding to reduce particle size for mineral liberation and separation is a cost intensive part of mineral production and should be optimized. This presentation will discuss a practical and unique ball mill media size optimization methodology developed by Metcom Technologies and Midland Research Center LLC with support from a number of operating mining companies and ME Elecmetal. The methodology is based on Metcom’s Functional Performance Equation, and in particular the ball mill grinding rate. The Functional Performance ball mill grinding rate has been shown to match a first-order rate equation describing the cumulative grinding rates of particles in the ball mill at the plant’s target size of interest. A step-wise procedure including before and after plant surveys, and a stage-gate pilot program using a torque instrumented pilot mill with a wide variety of prepared equilibrium media charges, will be described.
Rougher Flotation Cell Pulp Level Control to Increase Recovery
11:45 am | Mark Ferra, REXA Inc., Phoenix, AZ
Flotation is used in mining to produce concentrates of iron, copper and gold. In 2017, a copper mine near Globe, Arizona improved their rougher cells productivity using technically advanced electro-hydraulic actuators in the flotation process by enabling excellent tank pulp level process stability. Tank cell slurry volume can change due to feed/discharge fluctuations from neighboring tanks. When traditional pneumatic actuators are used, they have sluggish response times and overshoot due to the inherent physical property of air being compressible. Electro-hydraulic actuators have the benefit of hydraulic stiffness to deliver accurate and repeatable (0.1%) dart valve positioning. The results are an increase of the launderer copper concentrate grade by ~2-3%.
High-Efficiency Flotation Collectors for Magnetite Ores
1:45 pm | Peter Zhou and Joseph Zachwieja, Nouryon, Brewster, NY and , Jan-Olof Gustafsson, Henrik Nordberg and N. Smolko Schwarzmayr, Nouryon, Sweden
Reverse flotation of iron oxides using cationic surfactants to remove silica and silicate gangue materials is widely practiced by the iron ore industry in order to provide high-grade iron feed for the steel industry. Typical cationic collectors used for reverse flotation of silica and silicates are alkyl amines, alkyl amine salts, and more commonly ether monoamines or ether diamines. The two most commercially important iron oxide ores are hematite and magnetite. For reverse flotation of hematite ores, the state of art flotation collectors is based predominantly on ether monoamines, while collectors for magnetite ores are predominantly based on ether diamines. In our current study of the reverse flotation of magnetite ores, new, highly efficient collectors have been developed resulting in better froth profile than the traditional ether diamines. In one case in particular, it was observed that a new ether monoamine collector surprisingly gave a 20% higher dosage efficiency when compared with the standard ether diamine collector. Methods to improve biodegradability and toxicity of the cationic collectors will also be discussed. Details of the flotation performances of these new, high-efficiency collectors on magnetite ores from Europe and northern Minnesota will be presented, as well as the properties of the resulting flotation froths.
Control of declassified particles in classification and their impact on the business
2:15 pm | Debra Switzer, Weir Minerals, Madison, WI and Eduardo Cepeda, Weir Minerals, Santiago, San Bernardo, NA CL
High efficiency hydrocyclones are a necessity in the mining and mineral processing industry. Weir Minerals has enhanced the high efficiency hydrocyclone design with their new classification technology, known as Cavex 2. This design improves the control of classification of particles by decreasing the larger particles discharged through the underflow. By improving the control of your particle classification, you improve the bottom line and minimize loss at your plant. In this paper, Weir Minerals will discuss the benefits of the new design, the economic impact on grinding circuits and customer success stories.
Dick Kiesel, ArcelorMittal Minorca, Mine Inc., and and Shashi Rao, NRRI Coleraine Minerals Lab
Future Prospects for Taconite
10:45 am | Kenneth Reid, University of Minnesota, Eden Prairie, MN
From 1995 to 2017 US steel production via blast furnaces fell from 60% to under 40% while EAF steel rose to over 60%. This dramatic change has serious consequences for taconite pellet production and a transition from taconite pellets to a metallic iron product is required for a sustainable future for the Mesabi Range. Shaft furnace reduction of pellets and in-flight reduction of taconite concentrate are technologies with the potential to achieve this transition. Factors influencing the choice of technologies for future metallic iron production in Minnesota will be outlined and discussed.
A Review of Changing Iron Ore Demands for Alternate Iron Making Technologies
11:15 am | Nick Sosalla, Boyd Eisenbraun and Dennis Murr, Barr Engineering Co., Hibbing, MN
As steel production in the United States shifts more from blast furnaces to electric arc furnaces, the specifications of the products supplied by local mines will need to change to match changing demand. Specifically, low silica DR-grade pellets, DRI, or pig iron products will be necessary to supply iron units for electric arc furnace markets. This presentation will cover the history of the iron ore products supplied by the Minnesota iron range, historical and forecasted future trends for steel production, and both current and future opportunities for local Minnesota and Michigan iron ore production to satisfy the changing steelmaking demands.
Commercialization of the E-Iron Nugget Process
11:45 am | John Simmons, Carbontec Energy Corporation, Bismarck, ND
Carbontec Energy Corporation and Michigan Tech have developed the patented, low carbon footprint E-Iron Process that can convert unpelletized iron ore concentrates or iron bearing steel mill waste into pig iron grade iron nuggets using clean, low cost renewable biomass (i.e. hardwood or softwood) as the reductant in the place of coal or coke. A successful pilot plant program that utilized a linear furnace, produced high-quality iron nuggets on a 24 hour per day schedule utilizing three different iron ore concentrates and three types of biomass. Subsequent tests using steel mill waste as the feed stock also produced high-quality iron nuggets. Purdue University Northwest and Lawrence Livermore National Laboratory have recently completed a project that successfully verified the E-Iron technology which they modeled utilizing their high performance computer capabilities. Purdue University Northwest recently reported that the E-Iron Process can produce pig iron grade iron nuggets with a 65% reduction in carbon dioxide when compared to the blast furnace. Based on the success of these programs, E-Iron International, LLC was formed to commercialize the E-IronTM process. A three production line, 300,000 tonnes/year E-Iron Nugget plant will be built in Burns Harbor, Indiana. The initial $85 MM, 100,000 tonnes/year line is expected to be in production during the 3rd quarter of 2020.
Selective Carbothermic Reduction and Smelting (SCRS) Process for Beatification of Low-Grade Iron-Manganese Mineral Deposits
1:45 pm | Basak Anameric, NRRI Coleraine Minerals Research Lab, Coleraine MN
Manganese is a critically important element used by both the steel and energy industries. This is due to its unique chemical, physical and alloying properties. There is no substitute for manganese in these major industries so one-hundred percent (100%) of the demand is met via imports leaving the U.S. vulnerable to supply and demand pressures outside its control. The U.S. has manganese mineral deposits and the steel industry generates thousands of tons each year of waste-oxides containing various metals that are currently landfilled. Therefore, NRRI is advancing a novel process called selective carbothermic reduction and smelting (SCRS) to show that SCRS can be used to efficiently beneficiate manganese, and other minerals/metals such as iron, chromium, titanium, vanadium, aluminum and silica, from low-grade ores or steel industry waste-oxides.
Pilot-Scale Demonstration of Increasing Iron Recovery from Minnesota Oxidized Iron Resources
2:15 pm | Matt Mlinar, UMD NRRI, Coleraine, MN and Tom Petersen, Rodney Johnson and Brett Spigarelli, NRRI Coleraine Minerals Research Lab, Coleraine, MN
Minnesota’s magnetite taconite ore reserves will continue to decline over the course of the next several decades. Oxidized iron ore resources containing hematite and goethite are available but taconite mining companies avoid processing them because they are not recovered by low-intensity magnets; and, when recovered, they negatively impact pellet quality and productivity. In 2016 NRRI received a State grant through Minnesota’s Mining Innovation Initiative to investigate a new iron ore recovery technology developed by the NRRI called NatFlot. The study included iron ore and water characterization, bench and pilot-scale beneficiation via NatFlot, and pyrometallurgical tests to validate that NatFlot can be used to produce a concentrate suitable for making blast furnace-grade pellets from oxidized iron resources.
Cam Trembath, PolyMet Mining, Inc.
Algae Bioreactor for Removal of Manganese from Mine - Affected Waters
3:30 pm | Emily Anderson, Geosyntec, Minneapolis, MN and Satoshi Ishii and Cara Santelli, University of Minnesota, St. Paul, MN
Manganese is a common element in Minnesota’s geologic materials and can occur in mine-affected waters in its soluble reduced form. Manganese has a secondary drinking water standard of 50 ug/L and was nominated to the USEPA’s fourth contaminant candidate list (CCL4) by the Minnesota Department of Health. Manganese oxidation/precipitation occurs slowly under abiotic conditions, but the reaction rate can be several orders of magnitude faster when catalyzed microbially. The mechanism of microbial manganese oxidation remains unclear, however. This study characterized manganese-oxidizing microorganisms and tested manganese removal using a novel algae bioreactor in which algae provide fixed carbon to manganese-oxidizing microorganisms. Biofilm samples composed of algae and manganese-oxidizing microorganisms were collected from a manganese-oxidizing waterfall in Hokkaido, Japan. Using a culture-dependent approach, 68 manganese-oxidizing bacteria and fungi were isolated from the biofilm samples, including some not previously known to oxidize manganese such as Aeromonas, Skermanella, Ensifer and Aspergillus. A culture-independent approach was also used to characterize the total microbial community and determine how abundant the isolated manganese-oxidizing bacteria were in a manganese-oxidizing environmental sample. Biofilm samples were also used to develop a manganese-removing algae bioreactor. By adjusting operating parameters, the bioreactor was optimized to remove dissolved manganese to below detectable concentrations. This algae bioreactor could be scaled up for treatment of mine-effected water. Additionally, the bioreactor was designed to be coupled with sulfate reduction, which, when applied to mine wastewater could facilitate the removal of sulfate, along with iron or other metals of concern in mine-impacted waters.
Bio - Mediated Carbonate Precipitation for Dust Control at Mine Tailings Facilities
4:00 pm | Sean O’Donnell and Lucas deMelo, Geosyntec Consultants, Columbia, MD and Todd DeJournett and David Richardson, Geosyntec Consultants, Minneapolis, MN
Wind tunnel tests and benchtop experiments conducted on taconite tailings samples show that enzyme induced carbonate precipitation (EICP) and microbially induced carbonate precipitation (MICP) hold promise for mitigating windblown dust at mine tailings storage facilities (TSFs). Wind erosion of tailings is a significant challenge at many mine sites and must be controlled to comply with fugitive dust emissions requirements. Conventional methods for mitigating windblown dust at tailings facilities, including application of polymer or straw, or management of tailings basin water level may be prohibitively expensive, variably effective, or limiting to tailings basin operation. MICP and EICP present a cost-effective alternative method to control fugitive dust emissions at TSFs. MICP and EICP rely on the hydrolysis of urea (ureolysis) to induce precipitation of calcium carbonate (CaCO3), a cementing agent, on the tailings surface. Precipitation of CaCO3 results in an erosion resistant crust that may significantly reduce the risk of windblown dust from tailings facilities. Preliminary results of wind tunnel testing show that EICP-treated tailings are significantly less erosive than untreated tailings. Additionally, benchtop stimulation experiments show that in-situ stimulation of native ureolytic microbes for MICP may be possible at some TSFs, depending on site-specific conditions. Together, these results suggest that EICP and MICP hold promise for mitigation of windblown dust from TSFs.
Larry Kramka, Foth Infrastructure and Environmental, LLC
EMP, BMP, OMG: What does it all mean?
3:30 pm | Paul Eger, Global Minerals Engineering, Woodbury, MN; Courtnay Bot and Dave Meineke, Global Minerals Engineering, Hibbing, MN; Dave Adams, LaPointe Iron, Hibbing, MN
In 2015, LaPointe Iron Company and the United States Geological Survey entered into a cooperative study to investigate the presence and forms of amphibole minerals in the Ironwood Iron formation. About 1.1 billion years ago, the intrusion of the Mellen Complex produced conditions favorable to the creation of amphibole minerals, some of which might be fibrous or also known as elongated mineral particles (EMP). EMPs, if not properly managed, can produce environmental and health impacts. Samples from four drill cores and ten outcrop locations were collected over approximately 35 km of strike length. Samples were taken from each member of the iron formation present in the cores. X-ray diffraction, optical and scanning electron microscopy, and electron microprobe analysis were used to study the origin, distribution, morphology and chemistry of the amphiboles.
Most of the amphiboles were the result of contact metamorphism and decreased with distance from the contact. However, fibrous amphiboles were found in all cores. The more distal isolated occurrences are believed to be related to localized dikes and sills.
4:00 pm |
Jason Janisch, Jasper Engineering
Mill Girth Gear Inspections - RCM Approach for Reliability and Risk Improvement
3:30 pm | Jason Janisch, Jasper Engineering, Hibbing, MN and Tom Schumka, Global Inspections NDT, Kelowna, British Columbia
Girth gears are critical fixed assets at many mine sites, cement plants, lime plants, and paper mills and must be managed and maintained accordingly. Unexpected Mill and Kiln shutdowns are often very costly and girth gearing lead times are long. Spare inventory of these assets needs to be optimized accounting for both the high asset cost, the current risk of functional failure, and the consequences of a functional failure. In order to manage these assets, an RCM approach is key in providing realistic and tailored risk improvement solutions to assist customers’ businesses through reducing the cost of risk associated with gear teeth failure events.
A prominent failure mode of large girth gears is tooth fracture, which is often preceded by either severe macro-pitting, wear, and or fatigue cracks. Identifying and categorizing these potential failures and their severity enables the user to make informed decisions about replacement or flipping gearing. RCM Approach:
Each girth gear system needs its functions and desired standard of performance clearly identified, in its present operating context.
- Determine how the gear system can fail to fulfill its functions
- Determine the causes of each functional failure (failure modes).
- Determine what happens when each failure occurs (failure effects).
- Classify the consequences of failure (failure consequences).
- Determine what should be performed to predict or prevent each failure (tasks and task intervals).
- Determine if other failure management strategies may be more effective (one-time changes).
Prescriptive Analytics in Pump Condition Monitoring
4:00 pm | Robert Poulter, GPM, Inc., Duluth, MN
Mining operations are challenged with the need to improve process throughput, reduce downtime, and eliminate surprise outages while at the same time facing loss of experienced personnel and budget efficiencies. Pumps and other rotating machinery are critical to the mining and processing of mineral ores. This presentation examines the confluence of application knowledge with edge devices and machine learning to provide predictive and prescriptive guidance. Prescriptive Analytics go beyond Descriptive and Predictive Analytics by recommending one or more courses of action. Alerts, recommendations and diagnostics are delivered to maintenance and operations by way of desktop and portable devices.
Jeff Davis, Barr Engineering Co.
Emergency Response to Historic Pit Mine Washout Leads to Improved Resiliency, Functionality and Aesthetics
3:30 pm | Jessica Olson, Barr Engineering Co., Duluth, MN; Pete Kero, Barr Engineering Co., Hibbing, MN; Linda Johnson, Minnesota Department of Iron Range Resources and Rehabilitation, Eveleth, MN
On April 24, 2018, water from the historic Hector mine breached an earthen berm, lowering pit water levels 13 feet, washing sediment into the Embarrass River Diversion Channel, and taking out utilities and 200 feet of the Mesabi Trail bicycle path. The Minnesota Department of Iron Range Resources and Rehabilitation acted quickly to remove sediment from the channel and temporarily stabilize the wash-out ravine. Designs for trail and utility restoration were provided in August, and construction was 95% complete by November 2018, incorporating multiple features to enhance utility accessibility, site resiliency and aesthetics.
Bridging Soft Soils & Voids
4:00 pm | Phil Sledge, MACCAFERRI INC, Tucson, AZ and Marco Isola, Maccaferri, Inc, Williamsport, MD
Quarrying often occurs in urban areas, leaving abandon mines an eyesore and at a minimum a dangerous site claiming 20-30 lives per year in the US alone. (MSHA*) These mines are often left as massive holes in the ground or cuts into mountainsides. Falling debris is often a significant threat as is falling from a vertical highwall or drowning in a pool of water that has developed. Reclaiming of abandon quarries presents an opportunity for development of commercial, residential and recreational activities, but first one must address these ever present threats. Many developers are looking to stabilize the foundation, bridge any potential sinkholes and fill in these areas. Structural fill is often expensive and often times less care is employed when installing organic or other materials. This backfilling practice often creates voids in the backfill making the material susceptible to settlement. In the United Kingdom, developers have twice called on Ultra High Strength geogrids to bridge the voids beneath subdivisions built over abandon quarries. Another developer in Turkey is also employing the same solution beneath 600,000 sq meters of development. Multiple layers of equally spaced lower strength geogrids or one single Ultra High Strength (UHS) geogrid allow for an increase of the design safety factor of embankments, the reduction of differential settlements and a faster construction rate.. These geogrids have been used in the US to bridge sinkholes on highways and transfer the loads in pile caps. This technology may offer a cost effective way to bring closure to some of the abandon mines in the United States.
Logan Koskela, United Taconite, LLC
NRRI Fixed Bed Dynamic DRI Process Simulators
3:30 pm | Kevin W. Kangas, Brett Spigarelli, Don Fosnacht, Pat Casey and David Hauge, NRRI and Steve Schmit, Jackie Hitchingham and Jeff Potter, Gradient Technology
Shifts to higher efficiency electric arc furnaces (EAFs) have increased demand for a new generation of taconite pellets suitable for making direct reduced iron (DRI), but much of Minnesota’s taconite industry still produces pellets for older blast furnaces. Because bench-scale R&D efforts into upgrading Minnesota’s taconite producers have limited applicability at the commercial scale, NRRI has launched a project aimed at developing a new metallurgical test method called the Fixed-Bed Dynamic DRI Process Simulator that will help bridge this gap and enable Minnesota’s taconite industry to make the transition to modern pellet production. The project was funded through the 2016 Minnesota Mining Innovation Initiative. NRRI will present the design process and the final design selected for project execution.
Comprehensive Numerical Modeling of the Blast Furnace Ironmaking Process
4:00 pm | Chen Zhou, CIVS, Purdue University Northwest, Hammond, IN
Blast furnaces are counter-current chemical reactors, widely utilized in the ironmaking industry. Hot reduction gases injected from lower regions of the furnace ascend, reacting with the descending burden. Through this reaction process, iron ore is reduced into liquid iron that is tapped from the furnace hearth. Due to the extremely harsh environment inside the blast furnace, it is difficult to measure or observe internal phenomena during operation. Through the collaboration between steel companies and the Center for Innovation through Visualization and Simulation, multiple Computational Fluid Dynamics (CFD) models have been developed to simulate the complex multiphase reacting flow in the three regions of the furnace, the shaft, the raceway, and the hearth. The models have been used effectively to troubleshoot and optimize blast furnace operations. In addition, the CFD models have been integrated with Virtual Reality (VR). An interactive virtual blast furnace has been developed for training purpose. This work summarizes the developments and applications of blast furnace CFD models and the virtual blast furnace.