Stable hydrogen and oxygen isotope composition of waters from mine tailings in different climatic environments

The stable isotope composition of waters (delta H-2, delta O-18) can be used as a natural tracer of hydrologic processes in systems affected by acid mine drainage. We investigated the delta H-2 and delta O-18 values of pore waters from four oxidizing sulfidic mine tailings impoundments in different climatic regions of Chile (Piuquenes at La Andina with Alpine climate, Cauquenes and Caren at El Teniente with Mediterranean climate, and Talabre at the Chuquicamata deposit with hyperarid climate). No clear relationship was found between altitude and isotopic composition. The observed displacement of the tailings pore waters from the local meteoric water line toward higher delta O-18 values (by similar to +2% delta O-18 relative to delta H-2) is partly due to water-rock interaction processes, including hydration and O-isotope exchange with sulfates and Fe(III) oxyhydroxides produced by pyrite oxidation. In most tailings, from the saturated zone toward the surface, isotopically different zones can be distinguished. Zone I is characterized by an upward depletion of H-2 and O-18 in the pore waters from the saturated zone and the lowermost vadose zone, due to ascending diffused isotopically light water triggered by the constant loss of water vapor by evaporation at the surface. In zone II, the capillary flow of a mix of vapor and liquid water causes an evaporative isotopic enrichment in H-2 and O-18. At the top of the tailings in dry climate a zone III between the capillary zone and the surface contains isotopically light diffused and atmospheric water vapor. In temperate climates, the upper part of the profile is affected by recent rainfall and zone III may not differ isotopically from zone II.

La mine d'or / Élie Berthet

Collection : Nouvelles et romans choisis

Welland Canal Survey of Lands Isaac Kelly

Survey description of Isaac Kelly's land created by The Welland Canal Company. There is a written description of the land. The property is located on the east side of the Welland Canal. The land is a total of 1 acre and 3 roads.

Letter to S.D. Woodruff from Thomas Steers and W. M. Kelly

Letter to S.D. Woodruff from Thomas Steers and W. M. Kelly regarding the patent for Mrs. Clement. The writer says that he will write to Mr. Woodruff fully respecting the claim of the younger Clement, May 14, 1847.

Letter to Samuel D. Woodruff from Thomas Steers and W.M. Kelly

Letter to Samuel D. Woodruff from Thomas Steers and W.M. Kelly stating that they have been successful in getting the patent through for Mrs. Clement for Lot no.30, Concession 2 in Enniskillen. James Clement is not of age and he cannot transfer his right to his brother Joseph. There is no obstacle of the patent being issued in Richard’s name. There are some notes in pencil on this document. The document is torn, and stained, but text is not affected. The postmark on the outside is Montreal, June 26, 1847, June 25, 1847.

Les travailleurs miniers de l'Abitibi-Témiscamingue : la main-d'oeuvre de la mine Lamaque, 1948-1985

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Microbial response to restoration of tantalite mine soils in western Rwanda

Artisanal columbite-tantalite (coltan) mining has had negative effects on the rural economy in the great Lakes region of Africa through labor deficits, degradation and loss of farmland, food insecurity, high cost of living, and reduced traditional export crop production alongside secondary impacts that remotely affect the quality of air, water, soil, plants, animals, and human wellbeing. The situation is multifaceted and calls for a holistic approach for short and long-term mitigation of such negative effects. This study focuses on the effects of mine land restoration on soil microbiological quality in the Gatumba Mining District of western Rwanda. Some coltan mine wastelands were afforested with pine and eucalyptus trees while farmers directly cultivated others due to land scarcity. Farmyard manure (FYM) is the sole fertilizer applied on the wastelands although it is insufficient to achieve the desired crop yields. Despite this, several multi-purpose plants such as Tithonia diversifolia, Markhamia lutea, and Canavalia brasiliensis thrive in the area and could supplement FYM. The potential for these “new” amendments to improve soil microbial properties, particularly in the tantalite mine soils was investigated. The specific objectives of the study were to: (a) evaluate the effects of land use on soil microbial indices of the tantalite mine soils; (b) investigate the restorative effects of organic amendments on a Technosol; and (c) estimate the short-term N and P supply potential of the soil amendments in the soils. Fresh soils (0-20 cm) from an unmined native forest, two mine sites afforested with pine and eucalyptus forests (pine and eucalyptus Technosols), an arable land, and two cultivated Technosols (Kavumu and Kirengo Technosols) were analyzed for the physicochemical properties. Afterwards, a 28-day incubation (22oC) experiment was conducted followed by measurements of mineral N, soil microbial biomass C, N, P, and fungal ergosterol contents using standard methods. This was followed by a 12-week incubation study of the arable soil and the Kavumu Technosol amended with FYM, Canavalia and Tithonia biomass, and Markhamia leaf litter after which soil microbial properties were measured at 2, 8, and 12 weeks of incubation. Finally, two 4-week incubation experiments each were conducted in soils of the six sites to estimate (i) potential mineralizable N using a soil-sand mixture (1:1) amended with Canavalia and goat manure and (ii) P mineralization mixtures (1:1) of soil and anion exchange resins in bicarbonate form amended with Tithonia biomass and goat manure. In study one, afforestation increased soil organic carbon and total N contents in the pine and eucalyptus Technosols by 34-40% and 28-30%, respectively of that in the native forest soil. Consequently, the microbial biomass and activity followed a similar trend where the cultivated Technosols were inferior to the afforested ones. The microbial indices of the mine soils were constrained by soil acidity, dithionite-extractable Al, and low P availability. In study two, the amendments substantially increased C and N mineralization, microbial properties compared with non-amended soils. Canavalia biomass increased CO2 efflux by 340%, net N mineralization by 30-140%, and microbial biomass C and N by 240-600% and 240-380% (P < 0.01), respectively after four weeks of incubation compared with the non-amended soils. Tithonia biomass increased ergosterol content by roughly 240%. The Kavumu Technosol showed a high potential for quick restoration of its soil quality due to its major responses to the measured biological parameters. In study three, Canavalia biomass gave the highest mineralizable N (130 µg g-1 soil, P < 0.01) in the Kavumu Technosol and the lowest in the native forest soil (-20 µg g-1 soil). Conversely, the mineralizable N of goat manure was negative in all soils ranging from -2.5 µg N g-1 to -7.7 µg N g-1 soil except the native forest soil. However, the immobilization of goat manure N in the “cultivated soils” was 30-70% lower than in the “forest soils” signifying an imminent recovery of the amended soils from N immobilization. The mineralization of goat manure P was three-fold that of Tithonia, constituting 61-71% of total P applied. Phosphorus mineralization slightly decreased after four weeks of incubation due to sulfate competition as reflected in a negative correlation, which was steeper in the Tithonia treatment. In conclusion, each amendment used in this research played a unique role in C, N, and P mineralization and contributed substantially to microbial properties in the tantalite mine soils. Interestingly, the “N immobilizers” exhibited potentials for P release and soil organic carbon storage. Consequently, the combined use of the amendments in specific ratios, or co-composting prior to application is recommended to optimize nutrient release, microbial biomass dynamics and soil organic matter accrual. Transport of organic inputs seems more feasible for smallholder farmers who typically manage small field sizes. To reduce acidity in the soils, liming with wood ash was recommended to also improve P availability and enhance soil biological quality, even if it may only be possible on small areas. Further, afforestation with mixed-species of fast-growing eucalyptus and legume or indigenous tree species are suggested to restore tantalite mine wastelands. It is emphasized most of this research was conducted under controlled laboratory conditions, which exclude interaction with environmental variables. Also fine fractions of the amendments were used compared with the usual practice of applying a mixture of predominantly coarser fractions. Therefore, the biological dynamics reported in the studies here may not entirely reflect those of farmers’ field conditions.

Teoría de los constructos personales de G.A. Kelly aplicada al rendimiento académico.

Conocer la teoría de los constructos personales de Kelly, como posible aplicación al área de Educación. 99 sujetos, 53 hombres y 46 mujeres, de edades comprendidas entre los 13 y 19 años, todos ellos estudiantes de BUP becados, por lo que pueden clasificarse de clase baja. Los sujetos formaron tres grupos: primero A, primero B, y tercero. El diseño se dividio en 4 partes: a. En base a las puntuaciones obtenidas en el test de inteligencia, cada grupo se dividió en dos partes: el 25 por ciento con CI más alto forman un subgrupo y el 25 con CI más bajo forman otro subgrupo. b. En base a las calificaciones obtenidas: 25 por ciento de calificaciones altas y 25 de calificaciones bajas tanto en el apartado 'A' como en el 'B', el diseño es el del tipo de grupos apareados. c. En base al criterio de asignaturas fáciles y difíciles se forma un diseño 2x2x3, este apartado es una ampliación del apartado a. d. En este apartado, similar al anterior, se emplean los grupos divididos en base a las calificaciones, y se agrupan las asignaturas en fáciles y difíciles. De acuerdo con el formato del REP-test de Kelly, la estructura de esta técnica se divide en tres partes: elementos: asignaturas del plan de estudios de cada grupo; constructos: lo semajante forma el polo de la izquierda y lo diferente en el polo de la derecha; rejilla: cada sujeto debe puntuar en cada casilla, utilizando una escala del 1 al 5. Test de inteligencia general, TEA, SA, 1974. Calificaciones: de las actas correspondientes a la cuarta evaluación. Moda. Análisis de Cluster, programas de BMDP1M y BMDP2M, Dixon, 1982. Análisis de varianza, programa Reliability de SPSS, Nie y Hull, 1981. Frecuencia. Prueba Chi cuadrado. No se confirma que las personas más inteligentes tengan mayor complejidad cognitiva que las personas menos inteligentes. No se confirma la hipótesis de que las personas que obtienen mayor rendimiento académico tengan mayor complejidad cognitiva que aquéllos de bajo rendimiento. Hay un cierto apoyo para la hipótesis de que al evaluar asignaturas difíciles ocurre mayor complejidad cognitiva que cuando se evalúan asignaturas fáciles. Los sujetos consideran a una asignatura fácil o difícil según las buenas o malas calificaciones que hayan obtenido. Esto concuerda con los planteamientos de Kelly, 1955, de que las personas validan los constructos subjetivamente. En cuanto al grado de relevancia de los constructos, los sujetos atribuyen central importancia a la comprensión de la asignatura y del profesor y, en menor grado, da importancia a que la asignatura sea agradable.