Ecofriendly Control of Mine Tailings Dust through Establishment of Biocrusts

采矿业产生了大量的尾矿，即开采出有价值的含金属矿物后残留的粉状岩石。产生的尾矿被收集起来，以泥浆或浆体的形式运输到大型现场蓄水池。尾矿库的规模从几百英亩到几千英亩不等。尾矿浆中的水被回收再利用，而固体材料则留作长期储存。在干旱和半干旱地区，如美国西南部地区，尾矿可以通过风力传播，导致颗粒物排放。这种粉尘对环境的影响包括降低能见度、降低空气质量、污染地表水和土壤。虽然已经尝试了不同的方法来治理矿山尾矿粉尘，但它们都有局限性。迫切需要开发生态友好、经济高效的矿山尾矿粉尘治理方法。这项研究的总体目标是调查影响生物结壳(覆盖在表面的专门生物)在尾矿上形成的因素，并在多个尺度上评价生物结壳稳定的尾矿的物理、化学、力学和环境行为。这个项目的成功完成将通过发展新的基础知识造福社会，这些知识可能导致一种环保和成本效益高的粉尘控制技术，以解决尾矿粉尘的不利影响。将通过外展和教育活动进一步造福社会，包括在项目期间每年在亚利桑那大学指导和培训一名研究生和两名本科生。干旱和半干旱地区的尾矿容易受到风蚀，相关污染物可能以粉尘颗粒的形式散布在整个环境中，对环境和人类健康造成严重有害影响。本研究的总体目标是开发一种生态友好、成本效益高的可持续尾矿粉尘治理方法。为了实现这一目标，拟议的研究采取了多尺度和多学科的方法，将1)进行系统的实验室研究，以确定和优化蓝藻培养和尾矿生物结壳生长的参数；2)表征生物固结尾矿的宏观行为与微/纳米尺度特征，了解基于生物固结的稳定和粉尘控制的潜在机理；3)通过现场试验演示和验证集成生物聚合物稳定和生物固结技术的粉尘控制和其他环境效益。生态友好型尾矿粉尘治理技术是基于生物聚合物稳定化和生物除尘一体化的技术，可能为粉尘治理和环境保护提供一种新的范式。本研究系统地研究了不同因素对尾矿生物结壳形成的影响，并从多个尺度上评价了尾矿生物结壳的物理、化学、力学和环境行为。该项目的成功完成将阐明生物尘埃-矿山尾矿相互作用的基础科学，并有助于更好地理解基于综合生物聚合物稳定和生物尘埃建立的稳定和粉尘控制的基本机制。其他教育和外展活动包括通过亚利桑那大学夏季工程学院为K-12学生举办夏令营，在生物圈2开发和展示展览，以及指导本科生和研究生。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The mining industry generates a significant amount of mine tailings, pulverized rock that remains after the valuable metal-bearing minerals have been extracted. The generated mine tailings are collected and transported in the form of a slurry or paste to large on-site impoundments. The tailings impoundments range in size from a few hundred to a few thousand acres. Water in the tailing slurry is recovered for reuse and the solid material is left for long-term storage. In arid and semiarid areas such as the regions of the southwestern United States, mine tailings can become wind borne and result in particulate emissions. The environmental impacts of this dust include reducing visibility, degrading air quality, and contaminating surface water and soils. Although different methods have been attempted for mine tailing dust control, they all have limitations. There is an urgent need for developing ecofriendly and cost-effective methods for mine tailing dust control. The overarching goal of this research is to investigate the effects of factors on the establishment of biocrusts (specialized organisms covering the surface) on mine tailings and evaluate the physical, chemical, mechanical, and environmental behavior of biocrust-stabilized mine tailings at multiple scales. Successful completion of this project will benefit society through the development of new fundamental knowledge that could lead to an ecofriendly and cost-effective dust control technology for addressing the adverse effects of mine tailing dust. Further benefits to society will be achieved through outreach and educational activities including the mentoring and training of one graduate student for the duration of the project and two undergraduate students per year at the University of Arizona.Mine tailings in arid and semiarid areas are prone to wind erosion and the associated contaminants can be dispersed throughout the environment as dust particles, causing serious deleterious effects on the environment and human health. The overall goal of this research is to develop an ecofriendly and cost-effective method for sustainable mine tailing dust control. To achieve this goal, the proposed research takes a multi-scale and multi-disciplinary approach and will 1) conduct systematic laboratory studies to define and optimize the parameters for culturing cyanobacteria and growing biocrusts on mine tailings, 2) characterize the biocrust-stabilized mine tailings to relate the macro-scale behavior to the micro/nano-scale characteristics and understand the underlying mechanism of stabilization and dust control based on biocrust establishment, and 3) demonstrate and validate the integrated biopolymer stabilization and biocrust establishment technology dust control and other environmental benefits by conducting field tests. The proposed technology for ecofriendly mine tailing dust control is based on integrated biopolymer stabilization and biocrust establishment and may lead to a new paradigm for dust control and environmental protection. The study systematically investigates the effect of different factors on the establishment of biocrusts on mine tailings and evaluates the physical, chemical, mechanical, and environmental behavior of biocrust-stabilized mine tailings at multiple scales. Successful completion of this project will elucidate the fundamental science on biocrust-mine tailing interactions and lead to better understanding of the underlying mechanism of stabilization and dust control based on integrated biopolymer stabilization and biocrust establishment. Additional education and outreach activities include a summer camp for K-12 students through the Summer Engineering Academy at the University of Arizona, development, and display of an exhibit at Biosphere 2, and mentoring of undergraduate and graduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.