Browsing by Autor "Robert W. Nairn"

Now showing 1 - 9 of 9

A Rich Vein? Mining and the Pursuit of Sustainability
(American Chemical Society, 2010) Jaime M. Amézaga; Tobías S. Rötting; Paul L. Younger; Robert W. Nairn; Anthony-Jo Noles; Ricardo Oyarzún; Jorge Quintanilla
The removal of a nonrenewable natural resource such as metals or petrochemicals hardly meets the definition of “sustainable”. However the methods used to extract the materials can be designed for overall environmental protection. Theoretically controllable variables include water use, transportation methods, and potential remediation/landscape alteration for the postclosure period. Further, in the case of metals, recycling means that the long-term sustainability of such resources can be realized. Amezaga et al. review how mining practices have evolved to consider sustainability over the last few decades and remark on what challenges still need to be overcome.
Acid mine drainage at Cerro Rico de Potosí I: unabated high-strength discharges reflect a five century legacy of mining
(Springer Science+Business Media, 2011) William H.J. Strosnider; F. S. Llanos López; Robert W. Nairn
Acid mine drainage at Cerro Rico de Potosí II: severe degradation of the Upper Rio Pilcomayo watershed
(Springer Science+Business Media, 2011) William H.J. Strosnider; F. S. Llanos López; Robert W. Nairn
ANALISIS DEL CO-TRATAMIENTO PASIVO DE AGUAS RESIDUALES MUNICIPALES Y DRENAJE ACIDO DE MINAS EN CERRO RICO DE POTOSÍ, BOLIVIA
(2015) William H.J. Strosnider; Sergio Carvajal; Freddy Llanos-López; Robert W. Nairn; Rebecca Peer; Brandon K. Winfrey
"El drenaje acido de minas (DAM) es un problema a nivel mundial. El co-tratamiento pasivo de DAM con aguas residuales municipales (ARM) es una manera efectiva y de bajo costo que utiliza los nutrientes de ARM para tratar las concentraciones de metales y sulfato en DAM. Cerro Rico de Potosí, Bolivia es una de las grandes ciudades mineras en el mundo que tiene muchos problemas con el DAM. El objetivo de este estudio fue determinar velocidades de reacción de Al, Fe, Mn, Zn, y otros metales en DAM provenientes de un flujo de agua en Cerro Rico usando un sistema reactor de tres etapas. El DAM tenía un pH de 3.58, acidez de 1080 mg/L equivalente a CaCO3 conteniendo concentraciones de 12, 68, 17, y 550 mg/L de Al, Fe, Mn y Zn respectivamente. Las velocidades de reacción de Al, Fe, Mn y Zn fueron de 1.43, 2.09, 0.01 y 0.10 d-1, respectivamente."
ANALYSIS OF MUNICIPAL WASTEWATER AND ACID MINE DRAINAGE PASSIVE CO-TREATMENT AT CERRO RICO DE POTOSÍ, BOLIVIA
(2015) William H.J. Strosnider; Sergio Carvajal; Freddy Llanos-López; Robert W. Nairn; Rebecca Peer; Brandon K. Winfrey
Acid mine drainage (AMD) is a worldwide environmental problem. The passive co-treatment of AMD with municipal waste water (MWW) is a cost effective approach that uses nutrients in MWW in order to treat high concentrations of metals and sulfate found in AMD. Cerro Rico de Potosí in Bolivia is one of the biggest mining cities in the world, and it is constantly facing problems with AMD. The goal of this study was to determine the reaction rates of Al, Fe, Mn, Zn, and other metals found in an AMD discharge from Cerro Rico by a three-stage reactor system. The AMD had a pH of 3.58 and acidity of 1080 mg/L as CaCO3 equivalent containing 12, 68, 17 and 550 mg/L of dissolved Al, Fe, Mn, and Zn respectively. The reaction rates of Al, Fe, Mn, and Zn were 1.43, 2.09, 0.01, and 0.10 d-1, respectively.
Evaluating locally available organic substrates for vertical flow passive treatment cells at Cerro Rico de Potosí, Bolivia
(Springer Science+Business Media, 2013) B. Santamaria; William H.J. Strosnider; Maria R. Apaza Quispe; Robert W. Nairn
Removal of Less Commonly Addressed Metals via Passive Cotreatment
(Wiley, 2015) Rebecca Peer; Julie A. LaBar; Brandon K. Winfrey; Robert W. Nairn; F. S. Llanos López; William H.J. Strosnider
The viability of removing less commonly addressed metals (e.g., Cd, Cu, Ni, and Pb) in a passive cotreatment concept was tested using a microcosm-scale, three-stage batch reactor system in which acid mine drainage from an abandoned adit on Cerro Rico de Potosí and raw municipal wastewater from Potosí, Bolivia, were introduced at a 5:1 ratio. The acid mine drainage had pH 3.58, acidity 1080 mg L as CaCO equivalent, and elevated concentrations of dissolved Al, Fe, Mn, Zn, Cd, Cu, Ni, and Pb, among other metals/metalloids. The municipal wastewater had pH 9.05 and alkalinity 418 mg L as CaCO equivalent, with 5.6 and 38 mg L of nitrate and phosphate, respectively. Previous analyses noted substantial pH increase, phosphate removal, denitrification, and removal of Al, Fe, Mn, and Zn. Prompted by these results, subsequent analyses were conducted for the current study, which noted that dissolved concentrations of Cd, Cu, Ni, and Pb decreased by 78.5, 18.3, 25.5, and 45.9%, respectively. Additionally, concentrations of Ce, Cr, Gd, and La decreased throughout the system. The study revealed the broader applicability of passive cotreatment of acid mine drainage and municipal wastewater, specifically for removing metals that are often difficult to address with conventional passive treatment approaches, such as Cd, Cu, Ni, and Pb. Results could be applicable for treatment alternatives in developing and developed countries where these waste streams occur in close proximity.
THE PAILAVIRI TAILINGS DEPOSIT, POTOSÍ, BOLIVIA: EXTREME ACID ROCK DRAINAGE GENERATION
(American Society of Mining and Reclamation, 2012) A.A. Neptune; F. S. Llanos López; R.R. Callapa; K. Palmer; Robert W. Nairn; Joel Z. Bandstra; William H.J. Strosnider
The historic mining center of Cerro Rico de Potos, Bolivia is marked with many tailing piles, with the Pailaviri tailings deposit being of great concern. These polymetallic sulfide tailings release some of the highest concentrations of ecotoxic metals observed in natural waters. In order to obtain a deeper understanding of the deposit, water samples were taken in transects throughout the deposit. Total metal concentrations in the waters were extremes: Al (25-2.9 g/L), As (1700-330 mg/L), Cu (850-140 mg/L), Fe (100-24 g/L), Mn (110-70 mg/L), Pb (36-21 mg/L), and Zn (3.1-1.9 g/L). Dissolved concentrations were essentially equivalent indicating these metals were in aqueous phase. Sulfate ranged from 136 to 400 g/L. Due to the extremely acidic nature of the water, the pH probes quickly degraded and became inoperable, rendering accurate pH measurements impossible. These results provided evidence of highly toxic conditions and likely downstream impacts due to close proximity of Rio Huayna Mayu. The extremely elevated concentrations of metals indicate that the Pailaviri deposit may be reprocessed at a profit and safely disposed of, an option which should be investigated.
Unabated acid mine drainage from Cerro Rico de Potosí, Bolivia: uncommon constituents of concern impact the Rio Pilcomayo headwaters
(Springer Science+Business Media, 2013) William H.J. Strosnider; F. S. Llanos López; Julie A. LaBar; K. Palmer; Robert W. Nairn