Liquid Mud Research Articles

Characteristics of the micropseudokarst landforms in Pâclele Mari mud volcanic area (Romania)

In this paper, we present the results of the geomorphological study of the micro pseudokarst landfoms developed on Pâclele Mari mud volcanic site that belongs to the famous mud volcanic area Berca-Arbănași, Buzău Subcarpathians, Romania. Different types of pseudokarstic cavity formation can be observed in the area, especially in the sloping periphery of the mud volcanic area, where badlands developed (badland pseudokarst), and rheogene pseudokarst in the mud flows. The liquid mud material gets denser and wimple on the surface of the mud that flows in the trough, it compiles and then covers the liquid mud channel. These micro-size covered tunnels are similarly formed as lava tubes at the lava flows of real volcanic areas. In order to complement the field measurements, we carried out surveys with a DJI Phantom 3 and 4, and Mavic Pro quadcopter to determine the landforms for the photogrammetry. Granular composition tests were carried out on sediment samples collected in the mud volcanic area by a laser diffraction particle analyser.

Technical Assessment Of Mud Handling Planning With Dredger Pump In Mining Front Area Of Pt. Makmur Lestari Primatama, Southeast Sulawesi, Indonesia

The high intensity of rain can affect mining activities because rainwater will be collected and stored in the area with the lowest elevation. In mining areas that have the lowest elevation point, namely the pit area, this will have an impact on mining activities. The pit area will not be disturbed if water or eroded slopes will enter and be accommodated in well-made drainage and vice versa if drainage is not formed properly, water and mud will be retained and accommodated in the pit area. If the water and mud are left unchecked, the water will overflow and mining will be temporarily halted, affecting the previously planned mining system. In this case, the pit whose water has been pumped out leaves the mud at the bottom of the pit trapped, so action is needed to remove the mud from the pit area and the need for qualified tools according to the existing mud criteria. The mud at PT Makmur Lestari Primatama has an SG criteria of 1.39 (top elevation mud) - 1.5 (bottom elevation mud) with mud grains of 0.005mm to 2mm, it can be concluded that the mud has liquid mud criteria to hard mud. So that the determination of a tool to be able to move mud using a pump, the selection of this pump There are three important parameters: Grain size, Specific Gravity, and also variations in material concentration that must be considered because they can affect the total head or flowrate. The difference between the Slurry pump and the dredger pump is in the pumping process, the dredger pump is able to pump hard mud with the help of a little water while the slurry pump is difficult to pump hard mud because it requires quite a lot of water to pump it. Therefore, a dredger pump is chosen to move the mud in the mining area so that it can pump liquid mud to hard mud, the selection of this dredger pump is based on pump specifications including max capacity 120-200m3/h, solid handling 35mm - 60mm, speed 1180 RPM, and effieciency 46%-51%. The planning analysis of the use of dredger pumps uses the Bernoulli equation and the amount of mud that must be pumped using the USLE method. Based on the results of a series of studies that have been carried out, researchers found that the total potential erosion is 8,574.2 tons/year, the total actual erosion is 7,716.8 tons/year, and the total volume of mud that must be pumped is 5,074.86m3 with a slurry weight of 1,448.2 kg/m3. So the most ideal dredger pump for this purpose is Dragflow HY85A with a capacity of 210m3/h, pumping hours of 16.6 hours / day, pumping duration of 2 days 15 hours and efficiency of 40% using HDPE type 10 inch diameter pipe.

Cleaner operations “revolutionizing liquid mud plants with sustainable practices”

The global imperative for an energy transition towards cleaner and more sustainable practices is more pressing than ever. As the world seeks to reduce its reliance on fossil fuels and curb carbon emissions, industries must explore innovative solutions. One such solution is the adoption of electric forklifts, especially in sectors like oil and gas, which traditionally rely on diesel-powered machinery. This paper examines the environmental benefits of replacing diesel forklifts with electric ones, focusing on significant carbon reduction. We will discuss the various types of electric forklifts, their operational advantages, and their impact on reducing greenhouse gas emissions. Additionally, this study provides a detailed regional market analysis, including market size, growth trends, and the factors driving the adoption of electric forklifts. By highlighting the role of electric forklifts in the broader context of the global energy transition, this paper underscores their potential as a crucial component in achieving a sustainable and low-carbon future.

Experimental evidence for lava-like mud flows under Martian surface conditions

Large outflow channels on ancient terrains of Mars have been interpreted as the products of catastrophic flood events. The rapid burial of water-rich sediments after such flooding could have led to sedimentary volcanism, in which mixtures of sediment and water (mud) erupt to the surface. Tens of thousands of volcano-like landforms populate the northern lowlands and other local sedimentary depocentres on Mars. However, it is difficult to determine whether the edifices are related to igneous or mud extrusions, partly because the behaviour of extruded mud under Martian surface conditions is poorly constrained. Here we investigate the mechanisms of mud propagation on Mars using experiments performed inside a low-pressure chamber at cold temperatures. We found that low viscosity mud under Martian conditions propagates differently from that on Earth, because of a rapid freezing and the formation of an icy crust. Instead, the experimental mud flows propagate like terrestrial pahoehoe lava flows, with liquid mud spilling from ruptures in the frozen crust, and then refreezing to form a new flow lobe. We suggest that mud volcanism can explain the formation of some lava-like flow morphologies on Mars, and that similar processes may apply to cryovolcanic extrusions on icy bodies in the Solar System.

Resolved measurements of 13CDH3 and 12CD2H2 from a mud volcano in Taiwan

Resolved measurements of the relative abundances of 13CDH3 and 12CD2H2 from a Taiwan mud volcano confirm that thermogenic CH4 with a formation temperature of 150 °C is bubbling from a pool of liquid mud. Analysis for both doubly-substituted molecules provides confirmation that isotopic exchange equilibrium was achieved between methane isotopologues. Methane extracted from the headspace of core samples taken from sediments deposited proximal to the bubbling pool of mud shows small departures from isotopic equilibrium.

Loulé: the anatomy of a squeezed diapir, Algarve Basin, southern Portugal

The Loulé salt diapir grew through the Jurassic and Early Cretaceous, when tight subvertical curtain folds were developed. It was then squeezed during the Alpine orogeny in the Oligocene and Miocene. This produced an intense array of brittle faults, veins and brittle–ductile shear zones through most of the diapir. The diapir exhibits more localized shear and brittle structures than any other previously described diapir. The most unusual deformation structures are ‘streaky shear vein’ zones (a new term), with an average spacing of 1 – 5 m, and usually less than 30 cm wide. They consist of a central coarse-grained halite vein surrounded by parallel zones of wispy discontinuous shale streaks and recrystallized halite. A new mechanism is proposed for the development of these zones, where repeated pulses of fluid flow have caused extensive halite recrystallization and streaking-out of unlithified mud intercalated with crystalline halite. This explains the formation of wide zones of well-aligned mud streaks (now lithified to shale), but with only small amounts of simple shear offset observed across these zones (<0.2 m). The lower tips of the streaky shear vein zones exhibit splaying mud injection veins, which indicate that fluid overpressures preserved liquid mud from salt deposition at 200 Ma to the Alpine collision at 20 Ma.

The Men Who United the States: The Amazing Stories of the Explorers, Inventors and Mavericks Who Made AmericaSimonWinchester. London: William Collins, 2013.

Men Who United States: Amazing Stories of Explorers, Inventors and Mavericks Who Made America Simon Winchester. London: William Collins, 2013.In 2011, British journalist Simon Winchester achieved his dream of becoming an American citizen after several years of residence. experience proved cathartic, especially when an immigration officer at Kennedy Airport took one look at his passport and remarked, Welcome Home (x). Winchester admitted to feeling almost overwhelmed by at last now being a part of all of (xiii), more precisely defined as belonging to a culture dedicated to principles of unity and progress, the promise of a better place and of better times ahead (xiv).The Men Who United States celebrates achievements of those men and women who spent their lives trying to fulfill this objective. Many of them are familiar figures in American history - Lewis and Clark, George Washington, Thomas Edison, Samuel Morse, Alexander Graham Bell. Winchester looks at their lives in a refreshingly original way; he structures book according to five classical elements (wood, earth, water, fire, and metal) in belief that they lie at heart of all human achievement. Early explorers such as Lewis and Clark used wood as a basic component of their travels; they created wooden boats and kept themselves warm with wood-burning fires. Geologists in eighteenth and nineteenth centuries probed earth's surface for agricultural riches as well as to determine worth of land. America's rivers and streams were used as early highways and trade routes; later on they provided a major source of power which formed basis for creation of new frontiers. In subsequent centuries, there came invention of engines, which depended on firepower, whether they were fueled by steam, gasoline, or aviation. For telegraph, steel wire of telephone, iron mast of radio and television, and fiber-optic cables of Internet, metal was common factor.Within each of these five sections, Winchester looks at achievements of various luminaries: in water section, he discusses work of William Madure, a Scottish-born entrepreneur who helped to found American Academy of Natural Sciences and created a geological map of United States. Gouveneur Kemble Warren worked for four years on Warren Map, which represented definitive guide to western United States (109). Warren's map was a means to conquer earth, a way of dispelling fantasies about West that continued to dominate popular imagination.In water section, Winchester celebrates those who financed and implemented Erie Canal project, several of whom had no engineering experience whatsoever: The men who laid out routes were not surveyors, but judges. One of principal builders was an arithmetic teacher [... .] few could imagine knowing how to work a theodolite, pay out a surve check, or construct a pound lock gate (203). Yet they kept on with project, in belief that it would contribute to public good; not only would it create new trading opportunities, but it contributed to America's prestige worldwide: All Europeans [...] had already begun to admire [...] Erie Canal [...] longest canal in world (209). Later on in section, Winchester writes about Mississippi, which links nation from top to bottom, offering a kind of geographic strength, a degree of certainty, stability (229) to those who inhabit its banks. During Depression era, river lost this strength as billions of tons of topsoil were torn out by steel plows to be gushed out as liquid mud into sea. …

The Intervention of Earthen Heritage in Seismic Areas and the Conservation Charters

Earthquakes are recurring natural phenomena that cause cumulative damage to earth constructions that can lead to their collapse. The discovery of earthen architectural heritage in Peru, has led to the re-exposure of adobe buildings, increasing their vulnerability to seismic activity. How can we prevent protect them from further damage their loss and Due to their gradual and progressive destruction, earth constructions located in seismic areas constitute a critical and unique case. The structural response of stone masonry joined with mud mortar depends on the weakest of their construction materials: earth. This paper presents the criteria for structural conservation of earthen architectural heritage and tools for seismic-resistant reinforcement developed by field experts during the last 25 years. The concepts of reinforced earth and liquid mud injection, developed by the Pontifical Catholic University of Peru (PUCP) with support from the Getty Conservation Institute (GCI), are also included in this work. The article also analyzes recent cases of the re-intervention of earth monuments initially restored during the last century and re-destroyed by more recent earthquakes; offers solutions to this situation, ranging from the safest and friendliest to the most aggressive ones. Finally, I concludes expressing the urgent need to reassess the conservation criteria accepted by the International Charters ratified by ICOMOS and UNESCO regarding earthen architectural heritage located in seismic areas.

Medicine before the motor car

Medicine before the motor car

Axial-Force Transfer of Buckled Drillpipe in Deviated Wells

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 119861, "Axial Force Transfer of Buckled Drill Pipe in Deviated Wells," by S. Menand, SPE, H. Sellami, and A. Bouguecha, Mines Paris Tech.; P. Isambourg, Total S.A.; and C. Simon, SPE, Drillscan, originally prepared for the 2009 SPE/IADC Drilling Conference and Exhibition, Amsterdam, 17-19 March. The paper has not been peer reviewed. Axial-force transfer is an issue in deviated wells where friction and buckling phenomena take place. The general perception in the industry is that once drillpipe exceeds conventional buckling criteria, axial force cannot be transferred downhole. The full-length paper shows that, even though buckling criteria are exceeded, axial-force transfer still could be good if drillpipe is in rotation. Introduction Axial-force transfer is an issue in highly deviated wells, such as horizontal and extended-reach-drilling (ERD) wells where drag friction is significant and buckling may occur. These challenging wells are characterized by a long horizontal departure (HD) relative to the true vertical depth (TVD) of the well. The axial-force-transfer issue comes from insufficient tubular weight in the vertical, or low-deviation, section of the well to run the drillstring in the long horizontal section. To overcome this problem, drilling engineers sometimes use drill collars or heavyweight drillpipe above regular drillpipe to push the string downhole. The critical angle for which drillpipe can no longer move downhole because of its own weight is a function of the coefficient of friction, μ. Drilling and completion running-string designs for these increasingly complex wells are based on torque-and-drag results, and more specifically on buckling criteria, to determine if the string can be run in the hole. However, some recent papers and some full-scale experiments have shown that these conventional buckling models should be revisited. Because these models fail to predict buckling correctly, they also fail to predict axial-force transfer. Drilling-equipment manufacturers have developed some torque-and-drag-reduction tools to push the limits of ERD. Even though these tools are able to reduce friction in certain situations, accurate modeling still is needed to predict the axial-force transfer correctly and the occurrence of lockup. Tools, Techniques, and Methods Many methods and tools can be used to reduce friction and improve axial-force transfer. Friction reduction can be obtained with liquid or solid lubricants and mud additives, mechanical tools such as rollers, and by vibrating or rotating the drillstring. The goal of these tools is to reduce friction between the drillstring and borehole to improve axial-force transfer downhole. Torque-and-drag- or friction-reduction tools can be added to drillpipe or completion-running strings. They consist generally of nonrotating sleeves (or centralizers) or low-friction slider pads that reduce friction in the axial (sliding) or tangential (rotating) direction. Even though these tools can reduce the friction coefficient as much as 50%, these special devices require additional rig time for installation and removal and generally are used only in the cased-hole section.

Formation of mud ridge and runnels in the intertidal zone of the Severn Estuary, UK

Flow-parallel linear bedforms, consisting of ridges and runnels have been reported widely in soft and consolidated cohesive sediments within intertidal and subtidal coastal waters. Less frequent are reports of these systems incised into soft bedrock. Despite their common occurrence there are few data concerning the hydrodynamic controls on the initiation and maintenance of ridge–runnel systems. Rather, several hypotheses have been advanced to account for them. In tidal environments a theory based upon the evolution of ‘streamwise vorticity’ transverse to the main flow direction is favoured, and has been supported recently by detailed hydrodynamic data obtained from above a ridge–runnel system on an intertidal zone of the Severn Estuary, UK. In the present paper, a detailed description of the sedimentology of the same ridge–runnel system is provided and interpreted within the framework of the ‘streamwise vorticity’ hypothesis. This objective is accomplished by measurements of the morphology and sampling the bulk characteristics of the sedimentary ridges and runnels but also with reference to ridges and runnels incised into soft bedrock beneath the sediment body. Grain-size composition, sediment compaction, radionuclide distributions and elemental distributions and X-radiography are used to describe the sediment structures within ridges and their inferred histories of development. These descriptions are interpreted with respect to the known hydrodynamic climate and the deposition and erosion behaviour of the sediments in laboratory experiments using an annular flume. Runnels contain liquid mud at low tide but contain very little fine gravel and shell debris. In contrast, fine suspended sediment is present at high concentrations in the flow. Thus fluid evorsion, aided by a dense suspension of fine sediment that impacts the mud bed, must be the primary tool to initiate and maintain the runnels, rather than scour by a coarse bedload. The ridges are composed primarily of fine silt or sand laminae some of which are approximately horizontal but most of which are slightly domed upwards such that they drape the ridge topography. This relationship between lamination and form demonstrates that the ridges are distinct accretion units and not residual masses of un-eroded planar-laminated mud incised by runnels. Laminae thicken, or thin and pinch-out, or are truncated, laterally at the sides of the runnels. Truncation occurs probably by damped spanwise turbulence structures which were recorded at this location. A notable characteristic is that the mud in the upper portion of the ridges is of low density and low compaction whilst the sediment in the lower part is more dense and well-compacted; often the two units are distinct, being separated by major reactivation surfaces; the latter indicative of occasional stripping of the surface sediments from above a residual ‘core’ at the base. The presence of coarse-grained laminae and lenses and minor reactivation surfaces throughout the sediment body indicates that high energy conditions, possibly other than the Neap–Spring cycle, are also important in developing the ridges. In this respect, consideration of the erosion potential of deposited sediment, using field and flume data, shows that the relatively low density, low-compaction mud constituting the crests of the ridges is not readily eroded by the present-day Neap–Spring tidal flow regime. Further, for the same flow regime, when the shear stresses on the bed fall below critical for suspension, potential deposition rates are very low, which supports the interpretation of the coarse-grained layers and reactivation surfaces as indicators of the significant role played by additional high-stress events, such as storm surges, in ridge-erosion and rebuilding.

Modélisation tridimensionnelle de la salinité et de la turbidité dans l’estuaire de la Loire : couplage des processus

Click to increase image sizeClick to decrease image sizeThe Loire estuary management agency, the “Groupement d’Intérêt Public Loire Estuaire”, appointed Sogreah to study, develop and evaluate scenarios aimed at improving the hydrosedimentary functioning of the Loire estuary. This assignment notably includes a three-dimensional hydrosedimentary model of the estuary. This comprehensive model, built using the TELEMAC-3D modelling system developed by EDF-R&D, was compared with two large series of field measurements and with historical data, which has substantially increased the available knowledge of tide dynamics in the estuary. It has been proved that the presence of liquid mud in the inner estuary leads to a remarkable drop in the low-water levels, sometimes exceeding a metre. This means it is essential to couple the friction calculation and the maximum turbidity zone dynamics in order to gain an accurate appraisal of the impact of developments in the estuary. This discovery calls into question the traditional approach consisting in mapping friction as a function of the Loire discharge alone.

Iron Sulfides in Mudstones within the Carbonaceous Sequence of Donets Basin

The genesis of local compact segregations of iron sulfide (pyrite) in mudstones at the roof of some coal seams in the Donets Basin (Donbas) is examined. Arguments presented in the work show that sulfides were formed as a result of bacterial sulfate reduction and hydrogen sulfide generation in zones of organic matter concentration. The lack of any signs of influx of alien components testifies to in situ sulfide accumulations at the syngenetic or early diagenetic stage in bottom sediments of the basin. The shape and structure of pyrite segregations suggest that they could be “sulfide bioherms” occasionally subjected to mechanical deformation in a liquid mud under the influence of gravitational force or external mechanical (possibly seismic) loads. The obtained data can serve as an additional source of information pertaining to the formation conditions of sulfide ore deposits.

Mud Micro-washovers: An Intertidal Sedimentary Structure Indicating Atmospheric Exposure

The mud micro-washovers preserved on mud-coated, rippled sand flats in the macrotidal Severn Estuary occur as rows of small triangular lobes of sediment draped along the crests of ebb-oriented current ripples. The lobes point in the direction of the wind blowing when the flats were exposed and are thought on circumstantial grounds to record the wind-provoked rippling and splashing of liquid mud from the partly full ripple troughs up and over the crests.

The effect of substrate on burrowing in freshwater mussels (Unionidae)

The burrowing behaviour and rates of burrowing on sand, clay, mud, and gravel were determined for three species of freshwater mussels, Lampsilis radiata (Barnes), Anodonta grandis Say, and Elliptio complanata (Solander). Burrowing is achieved by a series of probing and digging movements by the foot, alternating with adduction or closing of the valves, and foot contraction, which cause the valves to be forced downwards into the substratum. Overall burrowing abilities were superior in sand in comparison to gravel in all three species, and E. complanata burrowed more rapidly than the other species in clay, sand, and gravel. Righting was not accomplished in soft liquid mud but burrowing was achieved by frequent, rapid adduction of the valves. Although righting by both E. complanata and A. grandis in a clay substratum was slower than in either sand or gravel, both species burrowed more rapidly in clay. Although there were differences in burrowing abilities between species and in the four substrata tested, the ultimate success in burrowing by all three species suggests that substrate is not the direct causal factor affecting local distribution of freshwater mussels.

The rate of infill and colonization by invertebrates of borrow pits in the Wash (S.E. England)

The outer borrow pit had a volume of 458 000 m3 when excavated and was further increased (by 22 500 m3) by the erosion of a lagoon, but was completely infilled in 3·5 years. The rate of sedimentation in the outer borrow pit, though declining with time, was considerably greater than previously recorded rates for intertidal banks and probably accounted for the paucity of fauna in the pit until completely infilled. Poorly sorted, unconsolidated, anaerobic, clay and silt sediments initially accumulated in the outer pit with up to 5 cm liquid mud at the surface, but after 2 years the predominant fraction was fine sand. Only Nepthys hombergii became established in the outer borrow pit before the pit was completely infilled, when the other pre-excavation, dominant species returned. The expectation that Capitella capitata and oligochaete species (opportunistic, ‘pollution indicator’ species) would be the first colonizers was not realized, though the oligochaete, Tubificoides benedeni was the most abundant species in the more consolidated, sandier sediments in the inner borrow pit 4 years after its excavation. The density of invertebrates in the inner pit was greater than the surrounding mud flats and was a focus for birds feeding in the area. The outer borrow pit after complete infill also had higher desities of bird food species than before excavation but was rarely visited by birds.

Faunal distributions in soft sediments of the Severn Estuary

The pattern of the infauna on participate shores of the southern coast of the Severn Estuary has been examined. Although mud predominates as the major beach substratum within the Estuary, sand beaches occur in both the lower and upper reaches. Liquid mud is found at l.w. in the middle reaches. Suitability of substratum is shown to be the most important factor influencing animal distribution. The number of infaunal species found in this survey did not increase markedly towards the mouth, in contrast to the pattern displayed by rocky shore animals. Several species were rare or absent on mud beaches close to the entrance of the River Avon and the possibility that sewage contamination is responsible for this is discussed.

The New Look in Oil-Mud Technology

Abstract Liquids having oil as the continuous phase long have been recognized as desirable for drilling and completing under certain conditions. Performance limitations, high costs and inconvenience of handling, however, have kept these oil muds from becoming accepted for widespread, general use. As previously used, the muds consisted of a body in g agent for oil, or primary emulsifier of water in the oil, and a series of supplementary additives to modify that principal component. In recent years a new approach to oil muds has been taken. Oil-dispersible colloids have been developed to perform specific functions in oil without dependence upon thickening of the oil or emulsification of water. Such colloids are typified by an organophilic clay for suspension of solids and an organic filtration control agent. These colloids are effective and stable at well temperatures presently encountered and do not require supplementary additives. They also are compatible with wetting agents and emulsifiers commonly used to provide tolerance for water and solids in oil muds. With the development of independently effective additives, oil muds now have much of the control and variability achieved with water-base muds. Field examples demonstrate that oil systems are being used successfully for drilling, coring and completing under extreme conditions of both low and high temperature and pressure. Field personnel utilizing ordinary rig equipment can prepare and control the oil muds. In areas of concentrated use, liquid mud facilities are providing further economy and convenience. Introduction Drilling fluids having oil as the continuous phase were first conceived and used in the middle 1930's. The value of these oil systems was immediately recognized, particularly in providing quicker and easier well completions and in increasing the initial rate of oil recovery. Oil systems have not been used extensively in the past because of performance limitations and high costs that can be attributed to the general inflexibility of the systems. This inflexibility resulted primarily because one basic component was used in an attempt to arrive at all mud properties. These oil systems can be compared with the early water-base muds. Water-base muds in the early years of drilling depended upon bentonite for rheological properties, suspension of solids and filtration control. As was learned with these earlier clay-water systems, one basic component cannot by itself provide all of ideal drilling-fluid properties. Today each water-base drilling-fluid property can be controlled with an exactness that was not believed possible even 10 years ago. Water-base muds are prepared to have certain properties to serve specific purposes, some examples of which include the following: the low- solids, low-viscosity, low-filtration fluids for hard-rock drilling; the high-solids, low-viscosity, low-filtration, inhibitive muds for shale drilling in areas of abnormal pressure; and the high-viscosity high- filtration muds that are left in wells between casing and tubing. Properties of these muds can be varied over wide ranges, and the muds can be converted from one type to another as the need arises. The control and variability of water-base muds are possible because of the large number of additives currently available for performing specific functions. With the development of new additives and new technology, oil muds now have achieved a similar variability in performance, cost and convenience. This paper describes the development and performance mechanisms of materials that independently control specific properties of oil muds. Also discussed in the paper are field applications of this new oil-mud technology. The Need for Oil Systems Oil systems have been used for many years to protect pay zones having productivities that can be impaired by water-base muds. Completions using oil muds with good filtration control consistently have resulted in greater initial production rates than could be obtained with water-base muds--often saving the time and cost of fracturing, acidizing, or extensive swabbing. Cores often must be obtained for use in reservoir-evaluation studies. JPT P. 1177^

OYACHI IN THE YONEZAWA BASIN, YAMAGATA PREFECTURE

Oyachi, situated in the northeastern corner of the Yonezawa Basin (Fig. 1), is a kind of bog lake with an area of 1020 ha, 950 ha of which is used as rice fields and the rest, 70 ha, is left as marsh. The rice fields here are classified into the two, the “Yachita” (marshy paddy fields) and the “Ukita” (floating paddy fields), the area is 700 ha. and 250 ha. respectively. The Yachita occupying the marginal part of Oyachi makes the muddy fields of powdered peat filled with water throughout the year. The Fkita which mainly occupies the central part is rather recently reclaimed fields. In Oyachi there run very many waterways and “Yachibune” (a kind of boat) is used to carry fertilizer or rice plants. When the uncultivated part or a ridge 4_??_6m. wide between rice fields is stamped violently, the ground roundabout shakes. The peat layer can be penetrated with boring stick by one hand, and as soon as it is pierced through, no resistance is felt. When the boring stick is drawn out, brown liquid mud blows out with methane for 5_??_7 seconds, then it rests at the depth of 3_??_5c.m. from the surface. The subsidence of the surface of Oyachi took place during 1931_??_1952 amounted 60_??_90cm. as shown in Fig. 2. Having an idea that Oyachi is a kind of bog lake, the writer made surveys in summer, 1953, at 423 points in Oyachi area on (a) thickness of the peat layer, (b) depth of the water lying beneath the peat, (c) thickness of the mud covering the base and (d) depth of the base from the surface of Oyachi. The results are shown in Fig. 3_??_8. (a) Although thickness of the peat layer (Fig. 3) ranges from 1m. to 2m., it is generally thick at the central part and thin at the marginal part of Oyachi. The peat deposits are saturated and underlain by water of low temperature, so that, for example, when the surface temperature of Ukita is 29.8°C, the temperature at a depth of 50cm. is only 1.4.9°C. Therefore, growth of rice plants is poor, and even alpine plants grow there, though the altitude of the area is only 212m. above sea-level. (b) Fig. 4 shows the depth from the surface of peat layer to that of the mud, namely the shape of the lake basin. The deepest point is 8m. in depth, and besides there are three sub-lake basins. The southern half of Uyachi has only a depth between 2 and 4m. Fig. 5 shows the depth of Lake Hakuryih, which i s situated in the deepest basin of the Oyachi bog lake. The maximum depth of water, however, is only 1.9m. That is to say, the bottom of the lake is a false bottom. (4) Fig. 6 shows the shape of base of the bog lake by contour lines in altitude above spa-level. As the result of borings, six rises and eight hollows were discovered in the base. The lowest (deepest) portion coincides with the area of Lake Hakuryu. Comparing Fig. 6 with Fig. 4, it is observed the location of the deepest zones of the base deviates to the east from those in the lake basin, and unevenness of the former is remarkable. (c) Fig. 7 shows the thickness of the mud deposited on the base and it amounts 8m. at the deepest part. It proves that the lower the base lies the more the mud has been deposited. Fig. 8 is the cross section along A-B (see Fig. 1) showing the relation between peat layer, water, mud and base. It had been planned to reclaim Uyachi by draining so as to make the area into a land suitable for cultivation, and the Biruzawa Reservoir with a pondage of 2, 190, 000m3. has been completed. Now the draining project is just to be carried on. But as the quantity of water in Oyachi bog lake amounts 20, 000, 000m3., it is necessary to make a draining canal from a point 12km. distant or to drain the area by electric power. After draining was accomplished, the writer thinks, it is necessary to bring enough soil from other places into the area or to take off the peat deposits from the area.

Liquid mud lifts ship : H. Chamberlin. ( Engineering News Records, Vol. 119, No. 6)

Liquid mud lifts ship : H. Chamberlin. ( Engineering News Records, Vol. 119, No. 6)