Between 1969 and 1981 open pit methods were used to recover the molybdenum ore producing some 317.5 million metric tons of mined rock from the Questa molybdenum mine, which went into nine rock piles.The mine is located in the Sangre de Cristo Mountains of Taos County in northern New Mexico.As part of a multi-disciplinary study to determine the effects of weathering on the long-term stability of the rock piles, we are searching for areas where weathering is occurring within the rock piles.Pyrite oxidation is a weathering process that typically generates large amounts of heat, making it a good candidate for detection by infrared thermography.We conducted surveys of surface temperatures on two rock piles during February and May 2004 using the FLIR SC 3000 infrared thermal camera.Thermal imaging of the rock piles revealed at one rock pile, a "heat vent" of roughly 40 m by 30 m that had the same maximum temperature of 18°C during February and May 2004.The maximum temperature of this heat vent was much larger than the ambient temperature in February (0-2°C) and May (4-6°C).During the February survey, the heat vent had little or no snow cover and appeared to be very wet, whereas the area surrounding the heat vent was snowcovered and frozen at the same time.The heat vent is likely the result of pyrite oxidation within the rock pile.Thermal imaging results from a second rock pile indicate that it is less likely to have a heat vent because the differences between the ambient and maximum surface temperature were much less significant.The small temperature difference could be explained by spatial variations in emissivity from local variations in rock thermal properties or moisture content or by a relatively small heat flux out of the rock pile.

Numerous faults crosscut the poorly lithified, basin‐fill sands found in New Mexico's Rio Grande rift and in other extensional regimes. The deformational processes that created these faults sharply reduced both fault porosity and fault saturated hydraulic conductivity by altering grains and pores, particularly in structures referred to as deformation bands. The resulting pore distribution changes, which create barriers to saturated flow, should enhance fault unsaturated flow relative to parent sand under the relatively dry conditions of the semiarid southwest. We report the first measurements of unsaturated hydraulic properties for undisturbed fault materials, using samples from a small‐displacement normal fault and parent sands in the Bosque del Apache Wildlife Refuge, central New Mexico. Fault samples were taken from a narrow zone of deformation bands. The unsaturated flow apparatus (UFA) centrifuge system was used to measure both relative permeability and moisture retention curves. We compared these relations and fitted hydraulic conductivity‐matric potential models to test whether the fault has significantly different unsaturated hydraulic properties than its parent sand. Saturated conductivity is 3 orders of magnitude less in the fault than the undeformed sand. As matric potential decreases from 0 to −200 cm, unsaturated conductivity decreases roughly 1 order of magnitude in the fault but 5–6 orders of magnitude in undeformed sands. Fault conductivity is greater by 2–6 orders of magnitude at matric potentials between −200 and −1000 cm, which are typical potentials for semiarid and arid vadose zones. Fault deformation bands have much higher air‐entry matric potential values than parent sands and remain close to saturation well after the parent sands have begun to approach residual moisture content. Under steady state, one‐dimensional, gravity‐driven flow conditions, moisture transport and solute advection is 102–106 times larger in the fault material than parent sands. Faults are sufficiently conductive to hasten the downward movement of water and solutes through vadose‐zone sands under semiarid and arid conditions like those in the Rio Grande rift, thereby potentially enhancing recharge, contaminant migration, and diagenesis.

Centrifugal methods are gaining increased attention for use in hydrologic experiments within partially saturated media. Through use of a Modified Invasion Percolation (MIP) model, we examine the influence of a stabilizing centrifugal (buoyancy) force on the invasion of a light non‐wetting fluid (e.g., air) into a heterogeneous porous media initially saturated with a denser, wetting fluid (e.g., water). Results show that while capillary heterogeneity controls phase structure outside of a centrifugal field, the influence of capillary heterogeneity varies with angular velocity in a centrifugal field. As the angular velocity is increased, the invasion processes and phase structure become increasingly insensitive to heterogeneity, regardless of its style or orientation. Because phase structure critically influences flow processes and petrophysical properties (pressure‐saturation, relative permeability, electrical resistivity, etc.), the design of centrifugal experiments must carefully consider this interplay between capillary heterogeneity and centrifugal force.

This chapter contains sections titled: Introduction Geologic Setting Study Methods Terminology Fault Zone Descriptions Permeability Discussion Implications Conclusions

Exhaustive characterization of a contaminated site is a physical and practical impossibility. Descriptions of the nature, extent, and level of contamination, as well as decisions regarding proposed remediation activities, must be made in a state of uncertainty based upon limited physical sampling. The probability mapping approach illustrated in this paper appears to offer site operators a reasonable, quantitative methodology for many environmental remediation decisions and allows evaluation of the risk associated with those decisions. For example, output from this approach can be used in quantitative, cost-based decision models for evaluating possible site characterization and/or remediation plans, resulting in selection of the risk-adjusted, least-cost alternative. The methodology is completely general, and the techniques are applicable to a wide variety of environmental restoration projects. The probability-mapping approach is illustrated by application to a contaminated site at the former DOE Feed Materials Production Center near Fernald, Ohio. Soil geochemical data, collected as part of the Uranium-in-Soils Integrated Demonstration Project, have been used to construct a number of geostatistical simulations of potential contamination for parcels approximately the size of a selective remediation unit (the 3-m width of a bulldozer blade). Each such simulation accurately reflects the actual measured sample values, and reproduces the univariate statistics and spatial character of the extant data. Post-processing of a large number of these equally likely statistically similar images produces maps directly showing the probability of exceeding specified levels of contamination (potential clean-up or personnel-hazard thresholds).

The performance of four alternative characterization technologies proposed for use in characterization of surficial uranium contamination in soil at the Incinerator and Drum Baling Areas at the Fernald Environmental Management Project in southwestern Ohio has been evaluated using a probabilistic, risk-based decision-analysis methodology. The basis of comparison is to minimize a computed total cost for environmental cleanup. This total-cost-based approach provides a framework for evaluating the trade-offs among remedial investigation, the remedial design, and the risk of regulatory penalties. The approach explicitly recognizes the value of information provided by remedial investigation; additional measurements are only valuable to the extent that the information they provide reduces total cost.

As part of the permitting and design of a power plant, the ability to supply cooling water subject to permit and availability constraints was investigated. As a first step, a synthetic hydrograph was estimated based upon a time series of river discharge downstream, the characteristics of the subbasin, and the point source discharger that significantly augments river discharge. The second step involved estimation of the frequency of forced facility shutdown due to insufficient water supply. This analysis treated as variables purchase of limited quantities of potable water and the quantity of stored water on site. In addition to estimating shutdown frequency, the frequency and duration of potable water purchase was calculated to facilitate cost estimation. Finally, a system for real-time monitoring of river discharge and change of facility operation in response to critical low river discharges was designed and implemented.

The direct count method for enumerating bacteria in natural environments is widely used. This paper analyzes the sources of variation contributed by the various levels of the method: subsamples, filters, and microscope fields. Based on a nested analysis of variance, we show that most of the variance (less than 80%) is caused by the fields and that the filters contributed nearly all of the remaining variance. The replication at each of the levels determines the total cost and error of a measurement. We compared several sampling schemes, including an optimal strategy which gives the lowest possible variance for a given cost. We recommend that preparing one filter from one subsample is adequate only if the samples are closely spaced in time or distance; otherwise, one filter should be prepared from two or preferably three subsamples. This sampling scheme emphasizes the importance of the highest level of replication. Our analysis shows that the accuracy of the direct count method can be substantially improved (by 20 to 50%) without a large increase in cost when the proper degree of replication at each level is performed.