In 2020, a confidential power client called upon Barr’s coal mining experience and geotechnical services to better understand the feasibility of a proposed 100 MW solar power project in the Appalachian Mountains. The proposed 1400-acre site was previously used as surface mining for mountaintop coal reserves and has since been graded and reclaimed. Barr’s mining and geotechnical team completed a desktop-based analysis of potential for future settlement, future underground mining, differential movement, and related risks to provide a better understanding of the past mining activities’ implications for siting and design.
To complete the analysis, Barr’s team first had to review site-specific information to identify the previous mining methods and associated depths, as well as locations of key mountaintop coal mining features such as valley fills, areas with surplus mine spoil locations, and impoundments. Barr’s mining engineers collaborated with GIS specialists to develop a means of calculating mine spoil thickness. Using LiDAR and InSAR data, our team then completed a settlement analysis of potential spoil movements and differential settlement.
In addition to the articulated potential risk associated with mine subsidence and anticipated strain resulting from differential settlement, Barr’s deliverable also provided recommendations on setbacks and layout and design concepts. Using this information to proceed with a more detailed design of the solar power project, Barr’s client appreciated our valuable insight based on our mining expertise.
Barr prepared an air permit application for a Minnesota facility that processes biogas generated by anaerobic digestion at three large dairy farms. The biogas is conditioned into pipeline-quality renewable natural gas (RNG) and injected into a natural gas pipeline.
Strategic permitting considerations centered on whether the three gas-processing facilities and the central processing plant should be covered under one permit or permitted separately. Barr used predicted biogas properties to help our client determine achievable operating scenarios that would keep emissions of sulfur dioxide and carbon monoxide below New Source Review and Title V air permitting thresholds if all facilities were grouped under one permit.
Population growth and increasing development density present significant challenges to protecting groundwater and surface waters in urban areas. One key element of water-resources stewardship is planning and building resilient wastewater-collection systems; another is the responsible and economical maintenance of them.
Barr updated the City of Bloomington’s sanitary-sewer model and comprehensive sewer plan. Our work included calibrating the model to actual measurements collected throughout the city. The existing-conditions model defined baseline conditions for evaluating the ways in which predicted future inflows would affect system capacity. We worked with city staff to pinpoint areas where anticipated development could exceed sewer capacity and identified potential capital improvements for accommodating the growth, such as modifications to lift stations, force mains, and gravity pipes. We also provided planning-level cost estimates for each conceptual improvement.
After updating the sanitary-sewer model, Barr trained city staff on model inputs, assumptions, and calibration; use and interpretation of simulation results; data exchange between the model and ArcGIS; and methods for evaluating additional system-improvement locations.
Finally, we documented our modeling and simulation results for both existing conditions and redevelopment scenarios and summarized that information for inclusion in the city’s wastewater and comprehensive sewer plan.
Sydvaranger Gruve AS (SVG) was established to rehabilitate the mining, railroad, and manufacturing plants at a former mine site and processing plant. SVG resumed mining magnetite ore and producing magnetite concentrate at a rate of 2.2 dry metric tons per annum (Mt/a). Later, a debottlenecking initiative helped increase output to 2.8 dry Mt/a, but SVG wanted to investigate options for increasing capacity to 5.6 dry Mt/a.
Barr’s team conducted a scoping study to evaluate options for expansion, including technical aspects and considerations for maximum utilization of existing facilities and infrastructure. Among the infrastructure assessed were the beneficiation plant location and equipment, crushing facility, tailings disposal system, and rail and overland conveyor transport. The client and its investment bank found the study useful for possible expansion and future investment opportunities.
Spring Lake Park Reserve is a scenic 1,200-acre park overlooking the Mississippi River in Dakota County, Minnesota, characterized by steep north-facing bluffs, expansive woodlands, and river terraces that support rare ecological communities. Over time, however, impacts from agriculture and climate change have contributed to deterioration of the park’s natural landscape, including increased stress on native plants and animals, active erosion of ravines, and invasive species encroachment.
Barr assisted Dakota County in developing a natural resources management plan to help staff ecologists and park planners determine priorities for ecological protection and regeneration. These included restoring native plant communities, regenerating soil and stabilizing steep ravines, and resolving human use conflicts. We also facilitated constituent engagement, provided detailed cost estimates, and identified grant funding sources.
The natural resources management plan has been praised for its clear, direct communication and helpful graphics, which allowed the County Board and Planning Commission to understand ecological issues and opportunities. This helped them to further prioritize and fund natural resources improvement in Spring Lake Park Reserve.
The Lansing Board of Water & Light’s electric modernization program (Lansing Energy Tomorrow) focuses on upgrading aging infrastructure to meet the region’s future electric-energy needs. Barr completed an electric-energy resource options study to assist with development of an integrated resource plan for replacement of the Eckert Power Station and preparation for the Clean Power Plan (the U.S. EPA’s regulations for reducing greenhouse gas emissions). The plan process is based on consideration of costs to customers, reliability as an energy source for the region, environmental stewardship, future uncertainty and risks, federal regulations, local generation capacity, and economic development.
Barr’s conceptual study of 17 resource options generated cost, schedule, plant-performance, and emission data that informed an analysis of the associated strengths, weaknesses, opportunities, and threats.
The Minnesota Pollution Control Agency hired Barr to develop a conservation-design prototype for a residential development in the City of Hanover. The green-infrastructure and landscape architectural design aimed to minimize environmental impact, provide great places for people to live, and preserve the city’s rural character. Conservation design is a process of preserving a site’s natural habitat and natural drainage as open spaces within a development. Small, manageable lots are placed around preserved open spaces to create distinct neighborhoods. Streets wind around preserved forests and wetlands, while pedestrian trails connect neighborhoods and allow children to visit friends without using streets. Another key goal was to preserve pre-development stormwater flow patterns and to retain and infiltrate stormwater on site.
After conducting an ecological site evaluation, Barr developed two plans for alternative housing densities and a conservation design ordinance that was adopted by the Hanover City Council. We also developed graphics and visuals to help the community better understand future development options.
The utility owns and operates a cogenerating power plant, providing electricity and drinking water to the City of Hibbing, Minnesota, and surrounding areas. It hired Barr in 2011 to provide a variety of routine electrical, controls, and instrumentation services to support its operation.
Barr’s work has included investigative services, design, start-up and commissioning, troubleshooting, and emergency call-out support. Due to limited internal engineering staff, we provide additional support with PLC and HMI programming, electrical and controls engineering, mechanical engineering of process and utilities distribution systems, and civil engineering for water-source and -distribution systems.
In 2020, Con Edison Development retained Barr to review the risk of subsidence due to abandoned underground coal mines at the Centerville Wind Project site in Appanoose County, Iowa. Barr completed a high-level desktop evaluation of abandoned underground mine risk to proposed wind turbine locations associated with two potential site layout options.
Barr reviewed existing publicly available information regarding abandoned underground coal mines near the proposed wind project site. Review evaluated the proposed wind turbine locations associated with potential project layouts with respect to coal resources and known abandoned underground coal mine locations. Barr’s engineering and mining experts also assessed the type of mining that was utilized, the length of time that had elapsed since active mining operations, and the potential for abandoned underground coal mines with unknown locations. Our team used this information to provide a risk assessment and recommendations for the layout and development of the wind project. Barr concluded that there was low risk of subsidence due to abandoned underground coal mines at the proposed wind turbine locations based on public data; however, due to the regional risk of unknown abandoned underground coal mines, an enhanced geotechnical investigation was recommended during the design phase of the project.
For the design phase geotechnical investigation, Con Edison Development retained Barr to conduct a geotechnical investigation at each proposed and alternate wind turbine location that extended below the approximate depth of the coal seam to evaluate the presence of abandoned underground coal mines. Barr’s geotechnical investigation included geotechnical borings at the proposed and alternate wind turbine locations, piezometer installation to monitor groundwater levels, laboratory testing, field electrical resistivity testing, laboratory thermal resistivity testing, and road subgrade testing. Barr compiled the data collected during the design phase geotechnical investigation and prepared a geotechnical engineering report. The report summarized findings of the geotechnical investigation and provided geotechnical recommendations for wind turbine foundation design.
The Prairie Island Indian Community has a long-term goal of reducing overall energy use while increasing use of renewable energy. Barr’s work for the tribe began with assistance obtaining a grant from the Bureau of Indian Affairs for installing long-term wind monitoring equipment at several sites to evaluate the feasibility of an on-site wind turbine project. In addition to looking at renewable energy options, Barr helped the tribe collect and summarize data on energy use and efficiency, including electricity and propane use at its facilities. This data enabled us to benchmark these facilities’ energy efficiency against that of similar facilities, and to access potential efficiency improvements, utility rate-structure options, and landscape-design features for reducing the use of energy and water. With this information as a foundation, we helped the tribe use a BIA Energy Development grant to evaluate its renew-able energy resource options, including feasibility assessments, as well as construction-cost estimates for a wind turbine, a biomass facility, and two types of solar collectors. We then helped the tribe incorporate that information into next steps for its energy plan.