Techniques in Restoration and Reclamation of Surface Mines Achieve a Powerfully Layered Narrative for Municipal Biosolids Generators and Mines Alike… ...So What's Stopping Us?

There have been several expert opinions expressed recently suggesting that few land application options for biosolids beneficial uses have as much benefit as mine reclamation. Also known as restoration, mine reclamation is experiencing a resurgence in popularity as a system where benefits of residuals are maximized. As our understanding of biosolids evolves, a re-assessment of how they can solve mine reclamation challenges and meet societal needs is a worthwhile endeavor. Mine reclamation is the process through which mined land is returned to productivity following mineral or aggregate extraction. Reclamation involves re-contouring, re-establishing hydrologic pathways, and placement of productive cover on the final topographic layout to enable the successful revegetation of the landscape. Many mines are challenged by shortages of topsoil required for reclamation. Soil shortages are a result of many variables, most notably the natural decomposition of organic matter and soil organic carbon, degrading both the quality and the quantity of salvaged soil. To address the challenge associated with topsoil quality degradation and quantity reduction, many mines import material. The common practice to address this challenge is the importation of topsoil from other areas on the landscape & an expensive and carbon-intensive process which creates a disturbance elsewhere. The use of biosolids and other organic residuals in reclamation views the residuals as both amendments, improving soil productivity, and as feedstocks in topsoil fabrication, which increases total topsoil quantity. Residuals use helps mines meet their reclamation standards if the site lacks topsoil resources. Their use also offers the opportunity to reconsider reclamation through the lens of economic growth, with reclamation leading to a new economy, supplementing the previous mining economy. Biosolids and other organic residuals are applied in many mine reclamation scenarios including one-time reclamation, and progressive efforts that occur throughout the mine site. One-time reclamation activities are completed when the mine site is no longer active. Progressive reclamation minimizes the disturbed area on the landscape by systematically reclaiming where mining is complete. ...Value to Mines Improved soils used in reclamation enable a range of opportunities for mine owners. Vegetation development is rapid, and can accommodate reclamation mixture grasses, productive agriculture, or even native forest species in the reclamation plan. The opportunity also exists to develop a highly productive biomass agroforestry system, which has the added potential of economic development on the land base. The use of biosolids or organic residuals may reduce the tendency of mines to lean on unsustainable mechanisms of reclamation, leading to improvements which may include: - Reducing or eliminating importation of non-renewable topsoil. - Minimizing or eliminating non-renewable fertilizer use. The use of fertilizers is often required on a regular basis post-seeding to achieve equivalent land capability to pre-disturbance conditions. - Gains in soil tilth, fertility, and water holding capacity improve establishment success and enables improved root system growth, resulting in vegetation resilience. - Acceleration in pedogenesis (soil formation and development) from regular organic matter inputs enable long-term ecosystem recovery and may be used even in the absence of topsoil placement, directly on subsoils. - Fabrication of topsoil from biosolids, mineral subsoil or spoil, and woody organic matter, for direct replacement of imported topsoil throughout the site. Reclamation programs using biosolids or organic residuals are sustainable, economical at operational scale, and have the capacity to improve land capability outcomes and carbon sequestration within the replaced soils. Value to Municipalities: Large municipalities rely on several biosolids and organics beneficial use options 'baskets'. The baskets offer contingency and resilience. If one opportunity is reduced, a resilient biosolids beneficial use program has capacity within the other baskets to mitigate this challenge. Mine reclamation offers a new development opportunity; a new basket offering long-term, sustainable beneficial use and substantial environmental benefit by comparison to other uses. Few narratives are as impactful as the imagery that arises from revegetation of a spoils landscape. Where municipalities consider the emotive impact of stories and images on how a utility residuals program is perceived, revegetation of landscapes has some of the greatest potential to elicit positive emotions about beneficial use, elevating utility residuals program status. Value to Communities: Pairing mine reclamation with the development of valuable biological feedstocks may spur the nascent bioeconomy, ultimately leading to cost recovery potential for the municipality and economic growth and jobs development for the community. This enables bioeconomies to develop where old mining economies are nearing end-of-life. The development of an economically stable beneficial use within the footprint of old mine sites may improve economics for biosolids beneficial use that will ultimately benefit communities, municipal generators, and taxpayers through reduced costs. Carbon Sequestration: By managing locally generated residuals at the mine site for reclamation, the mine and the municipal generator reduce their mutual carbon footprints through landfill diversion, reduced requirement for non-renewable fertilizer, and carbon sequestration in the reclaimed soils. Land end use objectives may also further opportunities for carbon sequestration, including the establishment of previously noted agroforestry systems such as short rotation intensively coppiced willow or switchgrass. These systems sequester carbon in belowground biomass and aboveground biomass can displace greenhouse gas intensive feedstock in energy production and bioproducts. Challenges and Impediments: The challenges and impediments to successful mine reclamation opportunities have much to do with a lack of education and awareness of the value biosolids and other residuals can bring to these landscapes. An assessment of several challenges, impediments, and successes through two decades of biosolids and residuals use in mine reclamation form the basis of our solution skillset to bring more mine reclamation opportunities to Municipal Generators as legitimate opportunities.