Transcript Document
Monitoring and Evaluating Reclamation Outcomes: A Case Study of the Roy Pray Mine By: Ashley Bembenek Environmental Consultant Image retrieved from Google Earth Roy Pray Mine Near Lake City, Colorado Denver Grand Junction Lake City Historic Mining near Lake City Historic Mining near Lake City - Gold and silver - From the 1870s to 1920s Palmetto Gulch - Heavily impacted area - 303(d) listed in 2002 for Cd, Cu and Zn - Led to additional data collection and TMDL From Kansas State Historical Society Image retrieved from Google Earth Roy Pray Mine Reclamation Project 2003: Bulkhead sealed at Roy Pray Adit 2005: Adit waste pile relocated and re-graded 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 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? Roy Pray WQ Monitoring Areas Below: Palmetto Gulch Above Roy Pray Below Roy Pray Roy Pray Mine Roy Pray WQ Monitoring Areas Above Roy Pray Roy Pray Mine Below Roy Pray Below: Palmetto Gulch Cadmium Concentrations: 1999-2010 Cadmium in µg/L 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 More recently, Cd concentrations have increased Copper Concentrations: 1999-2010 Dissolved Copper (ug/L) 45 40 Cu concentrations in Palmetto Gulch have remained stable Above Roy Pray 35 Roy Pray Mine 30 Below Roy Pray 25 Below: Palmetto Gulch Copper in µg/L Elsewhere, Cu concentrations have increased over time 1999 Increases above & at the mine adit do NOT account for all of increases measured below the mine 20 15 10 5 0 2000 2002 2004 2005 2006 2008 2010 Groundwater seeps interact with mine pool water or other low quality water--- Cu concentrations are very high 2010 data from below the Roy Pray has the highest Cu concentrations measured to date Zinc Concentrations: 1999-2010 Dissolved Zinc (ug/L) 14,000 12,000 Zn concentrations above Roy Pray & in Palmetto Gulch have remained stable Above Roy Pray Roy Pray Mine 10,000 Below Roy Pray 8,000 Below: Palmetto Gulch 6,000 Zinc in µg/L Zn concentrations initially declined at the Roy Pray Mine 4,000 2,000 0 1999 2000 2002 2004 2005 2006 2008 2010 Since 2005, Zn concentrations have risen at the mine and immediately below it Metal concentrations on the rise, what has flow done? Location Year Month Above Roy Pray Roy Pray Below Roy Pray Below: Palmetto Gulch 2000 July 0.34 0.03 0.51 1.87 June 1.62 NM 2.24 9.94 Flow (cfs) 2005 2010 September June July 0.01 0.64 0.17 0.04 0.01 NM 0.09 1.95 0.37 0.38 NM NM 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 Responsive Management Project data translated into information to direct further management actions Project partners have agreed to collect more water quality samples and additional data Additional reclamation strategies will be developed, as needed Conditions at the Roy Pray Mine highlight the need for post-reclamation monitoring and evaluation Questions or Comments… Additional questions: Ashley Bembenek [email protected] Image retrieved from Google Earth Image retrieved from Google Earth