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Published byPhilomena Preston Modified over 9 years ago
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Monitoring and Evaluating Reclamation Outcomes: A Case Study of the Roy Pray Mine By: Ashley Bembenek Environmental Consultant Image retrieved from Google Earth
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Roy Pray Mine Near Lake City, Colorado Denver Grand Junction Lake City
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Historic Mining near Lake City - Gold and silver - From the 1870s to 1920s From Kansas State Historical Society Image retrieved from Google Earth Palmetto Gulch - Heavily impacted area - 303(d) listed in 2002 for Cd, Cu and Zn - Led to additional data collection and TMDL
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Roy Pray Mine Reclamation Project 2003: Bulkhead sealed at Roy Pray Adit 2005: Adit waste pile relocated and re-graded
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Roy Pray Mine Reclamation Project Objectives Bulkhead sealed to reduce flow from the mine adit Tailings pile removed from direct contact with stream and re-graded to reduce erosion potential
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Post-Reclamation Water Quality Monitoring Objectives Have reclamation activities at the Roy Pray Mine reduced metal concentrations in surface water samples? How has flow from the adit and adjacent pre-existing seeps changed following reclamation activities?
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Roy Pray WQ Monitoring Areas Below: Palmetto Gulch Above Roy PrayBelow Roy PrayRoy Pray Mine
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Roy Pray WQ Monitoring Areas Below: Palmetto Gulch Roy Pray Mine Below Roy Pray Above Roy Pray
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Cadmium Concentrations: 1999-2010 Cd concentrations above the Roy Pray & in Palmetto Gulch have remained relatively stable through time Initially, Cd concentrations declined at the Roy Pray Mine & immediately below the mine Cadmium in µg/L More recently, Cd concentrations have increased
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Cu concentrations in Palmetto Gulch have remained stable Elsewhere, Cu concentrations have increased over time Increases above & at the mine adit do NOT account for all of increases measured below the mine 2010 data from below the Roy Pray has the highest Cu concentrations measured to date Groundwater seeps interact with mine pool water or other low quality water--- Cu concentrations are very high Copper Concentrations: 1999-2010 Copper in µg/L
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Zn concentrations above Roy Pray & in Palmetto Gulch have remained stable Zn concentrations initially declined at the Roy Pray Mine Since 2005, Zn concentrations have risen at the mine and immediately below it Zinc Concentrations: 1999-2010 Zinc in µg/L
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Metal concentrations on the rise, what has flow done? Flow from the mine adit is similar to pre-reclamation levels Flow from below Roy Pray Mine has likely increased over pre-reclamation levels Currently, metal loads are lower than pre-reclamation metal loads However, there is little evidence to suggest chemical or hydrologic stability at this location Additional data is needed to better understand current conditions
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Responsive Management Project data translated into information to direct further management actions Additional reclamation strategies will be developed, as needed Project partners have agreed to collect more water quality samples and additional data Conditions at the Roy Pray Mine highlight the need for post-reclamation monitoring and evaluation
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Questions or Comments… Additional questions: Ashley Bembenek abembenek@yahoo.com Image retrieved from Google Earth
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