Fine Material Content Research Articles

Hyperspectral Reflectance Assessment for Preliminary Identification of Degraded Soil Zones in Industrial Sites, India

The study explores the potential of next-generation satellite hyperspectral imaging systems for screening and predicting surface‐soil contamination and degradation by exploiting various spectral indices and signature‐matching techniques at a heavily industrialized area in India. The soil moisture content, desertification and salinity status, clay or fine material content, heavy metal content, vegetation health status, and stress levels were assessed from continuum-removed spectral reflectance values. Results indicated the presence of water in two tailings ponds, high salinity, and desertification values in most of the tailings ponds and dump sites, clay boundary liner along four ponds, high heavy metal indices along three ponds and all dump sites, highly stressed vegetation near all tailings ponds and coal dump sites, and pollutants in nearby water channels. The results suggest a strategy for the initial identification of priority areas for ground-based investigations and an alternative rapid methodology to monitor large industrial hubs in India.

Çankırı’da Bazı Kireçtaşı Agrega Kaynaklarının Betonda Kullanılabilirliğinin Araştırılması

In this study, the usability of limestone extracted from two different aggregate quarries located in Çankırı province as concrete aggregate was investigated. For this purpose, aggregate samples were taken from the two quarries and on the samples taken, sieve analysis, specific gravity, water absorption, bulk density, very fine material content, flakiness index, methylene blue, disintegration strength, abrasion resistance, freeze-thaw, alkali-silica reactivity, acid soluble sulfate and total sulfur tests were carried out. As a result, the results of the tests performed on aggregates obtained from the limestone quarries around Çapar village (Şabanözü, Çankırı), Seydiköy (Eldivan, Çankırı) and Doğu district (Korgun) were compared with the limit values given in the standards and the usability of these limestone as concrete aggregates was determined. According the tests performed on the aggregates it can be clearly seen that, that all properties of these aggregates are suitable according to the EN standards.

Effect of fine material content on the CBR of Iran saturated soils

Effect of fine material content on the CBR of Iran saturated soils

Effects of covering sand with different soil substrates on the formation and development of artificial biocrusts in a natural desert environment

In recent years, artificial biological soil crusts (BSCs)—i.e., the inoculation of soil with cyanobacteria—have become one of the most promising biotechnological strategies for preventing soil erosion and restoring soil functionality in degraded drylands. In order to use this biotechnology on a large scale, researchers must explore methods that enable rapid and largescale propagation of soil inoculum, as well as testing methods for developing artificial BSCs in the field. To help do this, we tested the effects of four soil substrates on the development of artificial BSCs in the Tengger Desert. Each soil substrate was collected from a different area in Zhongwei city in northern China and had different particle sizes and nutrient contents. We measured artificial BSCs characteristics according to the coverage, thickness, and wind erosion resistance of the BSCs analyzed. After 12 months, incubated artificial BSC coverage in incubated soils rose from 6% to 20%, and thickness rose from 2.94 to 4.06 mm. Incubated BSC coverage was positively correlated with fine material content (i.e., soil particle size less than 0.10 mm). There was also a positive relationship between coverage and soil organic matter, total nitrogen, and total phosphorus. Artificial BSC inoculation significantly improved soil resistance to wind erosion. These findings indicate that soil substrates improve BSC recovery rate over sand substrates by enhancing sand surface stabilization, increasing initial silt and clay content and nutrient content, especially soil organic matter content. Considering the scarcity of soil resources and the advantages of reusing soil resources, we suggest that left-over soils dredged from irrigation channels and abandoned farmlands can be used as substrate for the propagation of BSC inoculum.

Estimation of consistency limits of fine-grained soils via regression analysis: A special case for high and very high plastic clayey soils in Istanbul

Consistency limits are essential and simple design parameters that are utilized as standard entries of all kinds of soil investigation programs conducted for geotechnical projects which are constructed in/on fine grained soils. These limits also represent mineralogical and physical properties of clayey soils directly and used to estimate their strength and rigidity properties indirectly. However, the consistency tests are assumed as the simple and basic tests of geotechnical engineering investigations, but the effects of operator, calibration of the device and environmental aspects at the tests damage the reliability and correctness of results. In this paper, it is aimed to overcome these challenges by evaluating the consistency characteristics of clayey soils considering only the values of liquid limit of specific clays with the use of simple regression analysis. A database is prepared by using 500 soil investigation reports that are involving the site characterization information, laboratory and field tests of Istanbul Province European side clayey soils, including Avcılar, Esenyurt, Küçükçekmece, Büyükçekmece, Çatalca, Zeytinburnu, Bahçelievler, Bakırköy districts. 1523 liquid limit tests are obtained from the mentioned database for high and very high plastic clays. The regression analyses have been applied to query the parameter effect ratio on the consistent characteristics and relationships have been tried to be developed to evaluate the values of plastic limit and plasticity index directly from only liquid limit test applications. The effects of fine material content, depth and natural water content is also investigated. Verifications of the suggested equations have been done for different cases and comparisons are made with the well-known sources of literature. Consequently, strong equations are acquired to determine the plasticity index value in terms of liquid limit, liquid limit-depth, liquid limit-fine content, natural water content-fine content respectively based on the actual experimental tests conducted in Istanbul.

Characterization of electroosmotic drainage: application to mine tailings and solid residues from leaching

Mining is the most important economic activity in Chile, which is the largest copper exporter in the world. However, mining has significant environmental impacts, such as generating large amounts of solid waste. Due to the high moisture content of solid waste, physical stabilization problems can arise at disposal sites as a result of aqueous solutions trapped in solids not draining by gravity. Electroosmotic drainage has been proposed as a technique to reduce moisture and thus increase the stability of disposal sites. However, the question arises whether the volume of drained solution depends on the percentage of fine matter in the solid matrix. The experimental work reported here, based on an experimental factorial design, was carried out to address this question. The first part consists of an experimental design with synthetic solid matrices. The percentage of fine particles and the initial moisture level were defined as factors with three levels. The volume of drained liquid was defined as the response variable. The results showed that electroosmotic drainage was more efficient than gravitational drainage when the moisture content and the percentage of fine material were at their highest levels. The effect of the factors and their interaction was corroborated by an ANOVA. An equation was developed to describe the relationship between the response variables and the factors. Finally, considering the application of the technique in mining, tests were conducted on tailing samples and solid leaching residues. The tests showed that the technique is effective with tailings due to the high content of fine material and the initial moisture level. However, it was not effective with leaching residues due to the low initial moisture level and the low fine particle content.

Experimental study on the performance of gasification of corncobs in a downdraft fixed bed gasifier at various conditions

An experimental investigation on the gasification of corncobs was conducted in an 18 kW pilot-scale fixed bed system for power generation. The main objective was to determine the effect of gasifying corncob mixtures with fines content (particle size below 10 mm) on the performance of the system. To achieve the objective, a 2× 3 factorial arrangement was developed. The analysis considered three resistive loads connected to the generator (4, 8, and 12 kW) and two different size ranges of biomass (one with 100% of chips within the actual recommended size (10–40 mm)) and the other with a content of 15% of fine particles (particle size below 10 mm).An increase of 15% in fine material content in the feedstock and a stable electricity demand close to the rated capacity, significantly increased the temperature of the process and decreased the mean specific fuel consumption – SFC (2.06 kg/kWh at 67% of rated capacity). H2 and CO production increased by increasing reactor temperature, reaching concentrations of 16.7% and 17% respectively at the higher resistive load (12 kW). Cold gas efficiency varied in the range of 33.7%–37.0%, increasing slightly with the blend of fines content and higher applied load.

Key role of streambed moisture and flash storms for microbial resistance and resilience to long‐term drought

Abstract Spatial and temporal widening of drought periods together with occurrence of flash storm events are consequences of global change affecting temporary stream ecosystems. Streambed heterotrophic microbes and the key biogeochemical processes they carry on could be endangered by the strengthening of drought episodes. Here, we performed a 165‐day experiment through 12 streambed sediment columns to study heterotrophic microbial functional and structural responses to long‐term drought. Two sediment depths (surface and hyporheic) and leaf litter were monitored under three treatments: control (maintained in wet, pool‐like conditions), dry (5 months of drought), and dry–storm (5 months of drought including two flash storms). All treatments were then followed by rewetting. Surface sediment followed by leaf litter was the most affected by the long‐term drought as shown by the reduction of polysaccharidic enzyme activities and litter decomposition rate, although lignin decomposition was not affected. This resulted in a greater use of recalcitrant compounds which might be due to reduced labile organic matter sources and the greater resistance of fungi than bacteria to drought. Moreover, in surface sediment, bacterial viability and algal biomass were reduced while the production of extracellular polymeric substances was intensified with dryness, suggesting its potential role as survival strategy. Hyporheic sediments appeared more resistant to long‐term drought, and this might be linked to its slightly higher water content (2.5%) than the surface (0.5%) during drying together with a greater content of fine material that allowed fungi and bacteria to survive and extracellular enzyme activities to be maintained. Microbial resilience to long‐term drought in sediment and leaf litter was promoted by the flash storms as shown by the fast recovery of enzyme activities, bacterial viability and leaf litter decomposition rate in the dry–storm treatment, once rewetted. Storms might liberate previously occluded carbon sources that fuel the fast microbial reactivation as well as providing sediment moisture for microbial survival. Our results highlight that long‐term drought may compromise stream biogeochemical processes linked to organic matter decomposition and that microbes are highly sensitive to minimal water content changes. Thus, long‐term drought consequences could be mitigated by occasional precipitations or by natural streambed moisture.

Reconstruction of Late Pleistocene paleoenvironments in southern Germany using two high-resolution loess-paleosol records

Two loess-paleosol sequences from the Heilbronn Basin in southwestern Germany, Frankenbach and Talheim, have been investigated to gain information about environmental conditions during the last interglacial-glacial cycle. Since paleoenvironmental research on terrestrial archives is crucial for a better understanding of past climatic and environmental conditions, the profiles were studied using a multi-proxy approach. Applied methods include the analyses of grain-size distribution, element contents, sediment color, rock magnetism, micromorphology, and black carbon (BC) via benzene polycarboxylic acids (BPCA). The data reveal that the two profiles show large variations in conservation due to their different geomorphologic positions. Moreover, the results imply a subarctic climate with stable conditions during the Middle Pleniglacial (MIS 3) in-situ soil formation phase while the Lower Pleniglacial (MIS 4) was characterized by erosion and reworking of Eemian and Early Glacial (MIS 5) material but also by accumulation of aeolian material during the late Lower Pleniglacial (MIS 4) in Frankenbach. The results further suggest that the Rhine River floodplain has been a major source for the accumulated material in the two profiles, which indicates westerly wind directions during the time of accumulation. The low GSI and U-Ratio of Upper Pleniglacial (MIS 2) sediments, supported by the overall high content of fine material, imply a larger distance to the source area. We give an overview of loess in the Heilbronn Basin and place it in a wider context of loess in Western Europe.

Rheological and fresh properties of reduced fine content self-compacting concretes produced with different particle sizes of nano SiO2

In this study, colloidal nano SiO2 (CNS), which can be assumed as a multi-functional nano-technological material in cement-based systems, was utilized in an effort to reduce the total fine material content in self-compacting concrete (SCC) designs. The influence of CNS addition on flow properties and rheological parameters has been investigated. Three different average particle diameter of CNS which was used to modify the SCC mixtures are 35nm, 17nm and 5nm. CNSs were used at different amounts and total fly ash amount in the mix design was decreased step by step from 160kg/m3 down to 0kg/m3. The volumetric emptiness occurred by the reduction of fine materials was filled by aggregates. On fresh state, T500 slump flow time, slump flow diameter, V-funnel time, static penetration resistance, sieve segregation and visual stability index tests were performed. Moreover, rheological parameters such as static yield stress, dynamic yield stress and plastic viscosity were obtained by using a concrete rheometer. In this way, it was aimed to design SCC mixtures with reduced fine material content by benefiting of the viscosity modifying effect of CNSs with various sizes. Results have shown that the effectiveness of CNS, in an effort to reduce the fine material content in SCC design is very significant.

Grain size and geochemical study of the surface deposits of the sand dunes in the Mu Us desert, northern China

Material components and geochemical behaviour of desert deposits are closely related with the level and degree of the desertification. In this research, we systematically carried out a grain size and geochemical study of the surface sediments from fixed, semi‐fixed, semi‐mobile and mobile sand dunes and discussed their link with the desertification in the Mu Us Desert, northern China. Grain size results indicated that the main components of the different sandy sediments were predominantly 200–300‐µm coarse grain size. Along with the stronger desertification, the fine material content (clay and silt) and mean grain size (Φ) became lessened, while the coarse particle is remarkably increased due to the repeated wind sorting during that process. These sandy deposits were mainly transported by saltation and creep; the increased creep and decreased saltation and suspended components were probably a response to the lessened fixation degree of the dunes. Geochemical analysis demonstrated that the surface sandy deposits were mainly composed of SiO2, Al2O3 and Na2O, which was very similar to the geochemical constituents of the other deserts in northern China. These sandy surface sediments, with their relatively high Ca and Na content, incur little or no geochemical weathering, which is probably attributable to the arid conditions and the lack of effective weathering. Additionally, an A‐CNK‐FM diagram indicated that decreased Fe and Mg contents were possibly related to the stronger abrasion and sorting during the desertification process. Copyright © 2016 John Wiley & Sons, Ltd.

Utilization of polysaccharides as viscosity modifying agent in self-compacting concrete

Using new generation chemical admixtures makes it possible to produce self-compacting concretes (SCCs). However, to avoid the segregation of concrete, either the fine material content should be increased, or a viscosity modifying agent (VMA) should be used. In this study, the possibility of producing self-compacting concrete with a lesser amount of fine material than the conventional SCC while using a polysaccharide type VMA is investigated. For this purpose, three different polysaccharides welan gum, xanthan gum and starch ether – were used in varying dosages. Fly ash/Portland cement ratio was kept constant at 0.20 for all mixtures, while the binder content varied between 350 and 450kg/m3, except for the mixture with xanthan gum, which was tested only at the 400kg/m3 binder dosage. Slump flow and confined slump flow tests were conducted to determine self-compacting properties. Sieving, penetration and bleeding tests were performed to compare the segregation properties of fresh concretes. The strength and sorptivity properties of hardened SCCs prepared with and without VMAs were also investigated.

Granulometry and Surfactants, Key Factors in Desorption and Biodegradation (T. versicolor) of PAHs in Soil and Groundwater

High hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) is the most limiting factor for the remediation of polluted soils and aquifers. The present study analyzes the effect of three nonionic surfactants (Tween 80, BS-400, and Gold Crew) and the granulometry of soil (1 %, 5 %, 10 %, and 20 % of clay and silt) on desorption of a PAH mixture (fluorene, phenanthrene, anthracene, and pyrene). As a general trend, decrease of fine material content and increase of surfactant concentration raises desorption. However, some particularities have to be considered depending on granulometry together with the surfactant applied. Furthermore, increase of fine material content tends to reduce the importance of the PAH properties, e.g., Kow and solubility, in desorption. To complete the remediation process, biodegradation by Trametes versicolor was tested with the surfactant Tween 80. Results indicate that a high concentration of surfactant does not affect the efficiency of fungus bioremediation. Nevertheless, high fine material content in soil/aquifer can reduce the degradation rate. Moreover, desorption and biodegradation used synergically guarantee better overall results in the remediation of soils polluted by PAH mixtures than other methods that separate desorption and remediation.

A comparative study on the performance of sands rich and poor in fines in self-compacting concrete

Self-compacting concrete (SCC) as a special concrete, has practical advantages due to its mechanical performance and application easiness. However, a more careful study is needed at the stage of mixture proportioning. In order to produce SCC, a more voluminous but also a more viscous matrix is needed compared to concrete of normal workability. This may be achieved by using additional fillers with pozzolanic or inert nature. The employment of sands rich in fines may be a second alternative source of filler. However, the physical properties of sands rich in fines affect the performance of SCC in dual ways. In this study, the effects of the changes in the physical properties of sands (in particular the fine material content and type), on concrete performance were investigated. SCC mixtures containing four different sands (washed natural (WN) sand, washed crushed limestone (WCL) sand, crushed limestone sand with silt powder (CLS) and crushed limestone sand with clay powder (CLC)) were produced and the admixture requirements for each type of SCCs were determined. Test results suggest that, in order to produce SCC with the same consistency, admixture requirement may change with the physical properties of sands used. When compared to SCCs prepared with washed sand (poor in fines), approximately similar compressive strengths have been obtained by using CLS sand. On the other hand, CLC sand caused strength loss and increased the admixture demand for a targeted slump-flow of SCC. Due to the increased admixture content, setting times of SCCs prepared with CLC sand were also lengthened. The methylene blue adsorption value is a good indicator of clay content of sand. This test method was efficiently used for the selection of appropriate sand type incorporating high volumes of fine materials. Additionally, microstructural studies revealed some clues about the poor performance of SCCs prepared with CLC sand.

Geomorphic controls, riffle substrate quality, and spawning site selection in two semi‐alluvial salmon rivers in the Gaspé Peninsula, Canada

AbstractThe relationships between valley and channel morphology, spawning substrate quality (content of fine sediment < 2 mm) and the selection of spawning sites by Atlantic salmon (Salmo salar) were investigated along 45 km of two semi‐alluvial, valley‐confined rivers in the Gaspé Peninsula, Canada. Linear and logistic regressions confirm that Atlantic salmon prefer spawning at riffles providing good rather than mediocre or poor spawning substrate, as defined by the percentage sand and the Sand Index of Peterson and Metcalfe. However, exceptionally large concentrations of redds were observed on the few riffles located at island heads, with sub‐optimal substrate quality. This observation suggests that, in addition to content of fine material in the substrate, the morphology of spawning reaches may be a significant factor controlling the intensity of inter‐gravel flow through redds and the consequent selection of spawning sites. In the study systems, the quality of spawning substrate was controlled by ‘large‐scale’ geomorphic attributes at the scale of valley segments (1–5 km here): segments located within a wide valley were actively meandering, had higher sinuosity and bank erosion rates, generally lower shear stresses and presented somewhat higher sand content than segments confined by a narrow valley. Although sand contents were significantly higher, laterally unstable segments in wide valleys still harboured good to excellent spawning substrate overall. The study data do not allow the roles of variations in levels of riffle‐zone shear stress to be distinguished from those of cut bank fines input, to explain the observed inter‐segment association between valley width and riffle fines content. Copyright © 2004 John Wiley & Sons, Ltd.

EFFECTS OF MOISTURE AND FINE MATERIAL ON STATIC PRESSURE DROPS IN A BED OF GRAIN SORGHUM AND ROUGH RICE

Static pressure drops across columns of grain sorghum and rough rice were measured to determine the effects of grain moisture content, fine material, and airflow rate on airflow resistance. For grain sorghum, five levels of moisture content (12.0%, 13.5%, 15.0%, 16.5%, and 18.5% w.b.) and four levels of fine material (0%, 2%, 4%, and 8% by weight) were investigated with airflow rates ranging from 0.03 to 0.17 m 3 /m 2 s. For rough rice, four levels of moisture content (11.8%, 15.2%, 17.4%, and 19.5% w.b.) and four levels of fine material (0%, 1%, 3%, and 5%) were considered with airflow rates ranging from 0.05 to 0.38 m 3 /m 2 s. For both grains, airflow rate was the most significant factor affecting the static pressure drop. The static pressure drop decreased with increasing moisture content for both grains. However, the fine material content had a positive relation to the static pressure drop for grain sorghum but a negative relation for rough rice, possibly because of the large particle size of fine material in the rough rice sample. For both grains, the statistical model SP = a(Q) + b(Q)2 + c(Q)(mc) + d(Q)(fm) — where SP is static pressure drop; Q is airflow; mc is moisture content; fm is fine material content; and a, b, c, and d are constants — adequately described the relationship among static pressure drop, airflow, grain moisture content, and fine material with an R 2 = 0.997.

Soil organic matter dynamics in tiger bush (Niamey, Niger). Preliminary results

Some typical features of soil organic matter dynamics and soil texture were studied to discuss the particular spatial pattern of tiger bush in Niger and its dynamics. The soil texture through silt and clay contents showed a high variability in the vegetation arc as well as in the bare area. These variations were clearly linked to water/wind erosion and termite activity. Tiger bush soils showed a high capacity to store soil organic matter despite a moderate primary production, even in the bare area where the input of plant debris has been nil for many decades. The carbon content was higher within the vegetation arc (0.93 %) than within the bare area (0.45 %). Additionally, potential carbon mineralisation significantly varied in relation to the total carbon content and thus to primary production. Then, the vegetation arcs can be viewed as `fertility islands' as in many arid ecosystems. The measurements of δ13C showed a dominant contribution of C3 plants to the soil organic matter pool. Nevertheless, the contribution of C4 plants was not negligible. Two hypotheses could be proposed: a different mineralisation rate between C3 and C4 plants; or (ii) a better physical protection of C4 compounds against biodegradation. The soil variables depending totally or partly on biological factors, such as carbon and nitrogen contents, carbon isotopic composition, carbon potential mineralisation, did not show any symmetry in their variations along the studied transects. It was expected in the vegetation arc because the vegetation cover does not show symmetry in its specific composition and spatial structure. In the bare area, a clear asymmetry was observed on some of the variables: carbon content, fine material content and natural abundance of 13C. This supports the hypothesis that the vegetation arcs move upslope, and weakens the hypothesis of the alternance of contraction and spreading periods of the vegetation cover.

Effects of the process conditions during dry-defibration on the properties of cellulosic networks

The influence of structural changes caused by dry-defibration of the pulp on the mechanical properties of dry-formed cellulosic networks has been investigated. The effects of fibre length, fibre curl and content of fine material on these properties are discussed. The fluff pulps used were one CTMP-grade and two kraft pulps. The primary parameters used to describe the networks were the storage modulus, G′0 (measured at low strain amplitudes), and the critical strain, γc (at which the network yields), obtained from dynamic-mechanical measurements, and the maximum force, Fmax, sustained by the network and the maximum strain, γmax (at Fmax), measured with a specially constructed shear tester. It was noted that the storage shear modulus, G′0, and maximum force, Fmax, were affected in the same manner by the defibration conditions. To improve the deformability of the cellulosic network before rupturing, the ideal dry-defibration process should provide a greater number of free fibres per unit volume without producing fine material, at the same time as the curl index of the fibres should increase. Long and curled fibres are thus to be preferred. © 1998 Chapman & Hall

Grundmoräne versus Schlammoräne— two types of lodgement till in the Alpine Foreland of Switzerland

In the Aare River Valley between Berne and Thoune a mud till unit occurs together with lacustrine sediments in a complex relationship. The high content of fine material in the mud till is due to incorporation of lake sediments by the advancing Aare glacier probably during the most extensive glaciation of the Swiss Alps. Special attention is given to the evolution of the grain size parameters in vertical sequences in sections at Raintalwald and Räbli. The trend of vertical variation of the parameters reflects the origin of the mud till. Ground moraine and mud till may both be lodgement till but are texturally quite distinct, and the incorporation of pre‐existing sediments in the mud till is clearly demonstrated by the use of the grain size parameters.

Small Diameter Wells Drilled by Jet‐Percussion Methoda

AbstractObservation wells and access holes for neutron probe use were drilled by a jet‐percussion drill rig in coarse alluvial material near Tucson, Arizona. The method combines the jetting action which effectively removes loose materials with the percussion necessary to break up tighter formations and large particles. A unique feature of the equipment is the provision for simultaneous drilling and driving the casing to keep the hole open in loose formations. Washed samples of the material being drilled can be obtained from the recirculating water system. Drilling rates were from seven to ten feet per hour, and costs including casing were less than $1.50 per foot. Maximum depth is about 100 feet.Hydrologic study of a ground‐water reservoir requires access to the aquifer. Observations are made where the water table intersects the land surface, such as at springs or seeps, or through existing wells. However, wells are not always found in desired locations or are pumped so heavily that their usefulness as observation wells is impaired. Measurements are also made in the unsaturated zone with neutron moisture measuring equipment, which requires a small diameter cased access hole for the neutron probe.An observation well needs a diameter only large enough for access by measuring devices and must be immediately responsive to changes in aquifer water level. For neutron probe use, the required diameter is about two inches, and the well must have no significant effect on moisture movement in the unsaturated zone. To meet these requirements the drilling process should have no lasting effect on the formation surrounding the well. Finally, since the wells have no economic utility, construction cost must be low.A network of observation wells and neutron probe access holes was drilled as part of a project to evaluate the natural recharge from Rillito Creek near Tucson, Arizona. The formation along the creek bed is a coarse alluvial outwash containing almost no clay, considerable running sand, and some large gravel and boulders. Commercial churn (percussion) and hydraulic rotary drills, commonly used for drilling in this area, were first tried but encountered much difficulty in the loose materials.Previous investigators used jetting equipment drill small diameter holes in a variety of alluvi formations (Cederstrom and Tibbitts, 1961; Bowma: 1911; and Pillsbury and Christiansen, 1947). Howeve in most cases, either open hole drilling was used because the fine material content and the limited numb. of boulders or large gravel particles made this methc possible, or drilling mud was used to maintain th hole. The jetting method uses water pumped unde pressure through hollow rods and a drill bit to loose the material and carry it to the surface. The jettin water receives little aid from the drill in loosenin the material to be removed. Usually the drill cutting are settled out in a tank or basin, and the water i recirculated.