Search

The identification and quantification of Antarctic Pygoscelis penguin colonies depends increasingly on recognition of the characteristic optical properties of guano deposits, but almost all knowledge of these properties until now has been compromised by resolution and atmospheric propagation effects. Here we present hyperspectral reflectance data in the range 350–2500 nm, collected in situ from fresh guano deposits in Pygoscelis penguin colonies on Signy Island, South Orkney Islands. The period of data collection included the transition from predominantly white guano to the pink coloration characteristic of a krill-rich diet. The main identifiable features in the spectra are a broad absorption feature centred around 550 nm, responsible for the pink coloration and identified with the pigment astaxanthin, as well as several water absorption features. Variations in these features are responsible for differentiation between spectra. From these results we propose two spectral indices suitable for use with satellite data, one of which responds to the presence of astaxanthin in the guano and the other to water. Our results do not allow us to differentiate between penguin species from their guano, but do suggest that the breeding phenology of Pygoscelis penguins could be determined from a time series of multispectral imagery.

The identification and quantification of Antarctic Pygoscelis penguin colonies depends increasingly on recognition of the characteristic optical properties of guano deposits, but almost all knowledge of these properties until now has been compromised by resolution and atmospheric propagation effects. Here we present hyperspectral reflectance data in the range 350–2500 nm, collected in situ from fresh guano deposits in Pygoscelis penguin colonies on Signy Island, South Orkney Islands. The period of data collection included the transition from predominantly white guano to the pink coloration characteristic of a krill-rich diet. The main identifiable features in the spectra are a broad absorption feature centred around 550 nm, responsible for the pink coloration and identified with the pigment astaxanthin, as well as several water absorption features. Variations in these features are responsible for differentiation between spectra. From these results we propose two spectral indices suitable for use with satellite data, one of which responds to the presence of astaxanthin in the guano and the other to water. Our results do not allow us to differentiate between penguin species from their guano, but do suggest that the breeding phenology of Pygoscelis penguins could be determined from a time series of multispectral imagery.

Cross-shore exchange between the surf zone and the inner shelf is investigated using Lagrangian and Eulerian field measurements of rip current flows on a rip-channeled beach in Sand City, California. Surface drifters released on the inner shelf during weak wind conditions moved seaward due to rip current pulses and then returned shoreward in an arcing pattern, reentering the surf zone over shoals. The cross-shore velocities of the seaward- and shoreward-moving drifters were approximately equal in magnitude and decreased as a function of distance offshore. The drifters carried seaward by the rip current had maximum cross-shore velocities as they exited the surf zone and then decelerated as they moved offshore. The drifters moving shoreward accelerated as they approached the surfzone boundary with maximum cross-shore velocities as they reentered the surf zone over shoals. It was found that Stokes drift was not solely responsible for the onshore transport across the surfzone boundary. The cross-shore diffusivity on the inner shelf was greatest during observations of locally contained cross-shore exchange. These field observations provide evidence that the cross-shore exchange between the surf zone and inner shelf on a rip-channeled beach is due to wave-driven rip current circulations and results in surface material being contained within the nearshore region., Hydraulic Engineering, Civil Engineering and Geosciences

Cross-shore exchange between the surf zone and the inner shelf is investigated using Lagrangian and Eulerian field measurements of rip current flows on a rip-channeled beach in Sand City, California. Surface drifters released on the inner shelf during weak wind conditions moved seaward due to rip current pulses and then returned shoreward in an arcing pattern, reentering the surf zone over shoals. The cross-shore velocities of the seaward- and shoreward-moving drifters were approximately equal in magnitude and decreased as a function of distance offshore. The drifters carried seaward by the rip current had maximum cross-shore velocities as they exited the surf zone and then decelerated as they moved offshore. The drifters moving shoreward accelerated as they approached the surfzone boundary with maximum cross-shore velocities as they reentered the surf zone over shoals. It was found that Stokes drift was not solely responsible for the onshore transport across the surfzone boundary. The cross-shore diffusivity on the inner shelf was greatest during observations of locally contained cross-shore exchange. These field observations provide evidence that the cross-shore exchange between the surf zone and inner shelf on a rip-channeled beach is due to wave-driven rip current circulations and results in surface material being contained within the nearshore region., Hydraulic Engineering, Civil Engineering and Geosciences

Novel observations of surface grain-size distributions are used in combination with intra-wave modeling to examine the processes responsible for the sorting of sediment grains on a relatively steep beach (slope?=?1:7.5). The field observations of the mean grain size collected with a digital camera system at consecutive low and high tides for a 2 week period show significant temporal and spatial variation. This variation is reproduced by the modeling approach when the surf zone flow-circulation is relatively weak, showing coarse grain sizes at the location of the shore break and finer sediment onshore and offshore of the shore break. The model results suggest that grain size sorting is dominated by the wave-breaking-related suspended sediment transport which removes finer sediment from the shore break and transports it both on-shore and offshore. The transport capacity of wave-breaking-related suspended sediment is controlled by the sediment response time scale in the advection-diffusion equation, where small (large) values promote onshore (offshore) transport. Comparisons with the observed beach profile evolution suggest a relatively short time scale for the suspended sediment response which could be explained by the vigorous breaking of the waves at the shore break., Hydraulic Engineering, Civil Engineering and Geosciences

A sequence of daily beach surveys acquired over one month covering an area larger than 100,000 m2, was analyzed to study morphological changes resulting froma cluster of storms. The beach response was highly variable in both the cross- and alongshore. A cumulative storm effect was not observed, despite one storm being characterized by a 10-year return period that had significant wave height (Hs) of 8.1 m and a peak wave period (Tp) of 17 s. Instead, storms that can potentially cause significant erosion in terms of Hs had a limited effect on the morphology because the large wave height was coupled to either neap tides, normally-incident short-waves (f N 0.04 Hz), or low levels of infragravity (0.004 b f b 0.04 Hz) energy. Multiple linear regression analysis shows that volumetric changes in the upper part of the beachface are explained by offshore wave characteristics (period, height and direction), tidal range or by infragravity energy in the inner surf zone (assessed using pressure and velocity measurements). The results indicate that it is not possible to scale-up single-storm erosion studies into predictions of cluster-storm erosion.

Novel observations of surface grain-size distributions are used in combination with intra-wave modeling to examine the processes responsible for the sorting of sediment grains on a relatively steep beach (slope?=?1:7.5). The field observations of the mean grain size collected with a digital camera system at consecutive low and high tides for a 2 week period show significant temporal and spatial variation. This variation is reproduced by the modeling approach when the surf zone flow-circulation is relatively weak, showing coarse grain sizes at the location of the shore break and finer sediment onshore and offshore of the shore break. The model results suggest that grain size sorting is dominated by the wave-breaking-related suspended sediment transport which removes finer sediment from the shore break and transports it both on-shore and offshore. The transport capacity of wave-breaking-related suspended sediment is controlled by the sediment response time scale in the advection-diffusion equation, where small (large) values promote onshore (offshore) transport. Comparisons with the observed beach profile evolution suggest a relatively short time scale for the suspended sediment response which could be explained by the vigorous breaking of the waves at the shore break., Hydraulic Engineering, Civil Engineering and Geosciences

The object of this thesis is to present a conversion plan for the existing Liberty Ships involving least cost to increase their potential as a national defense investment by increasing their speed to 15 knots. Approximately 1500 Liberty Ships are now in the reserve fleet, costing originally upwards of Six Billion Dollars. They are regarded as obsolete and a questionable defense potential because of speed limitations .This proposal is based on the following: Scrap one ship and save propulsion machinery; modernize one ship by using the additional propulsion machinery obtained to double the power, and lengthen the bow 24 feet to improve resistance . Details of machinery changes : Move forward engine room bulkhead forward 17' 6" to make room for the two additional boilers; mount two main engines each 6' 6" from the centerline of the ship in the same longitudinal location with the starboard engine HP cylinder placed aft so that the engine driven auxiliaries and main condenser retain the same position relative to this main engine; install single reduction gears for engine speed of 76 RPM to 85 RPM of propeller; use new line and tail shafting, new stern tube, and new 18' propeller; necessary auxiliaries duplicated using those from scrapped ship. The new bow is faired into existing Station No. 3 at approximately frame 30 and has the following characteristics: Cut -up starting at 53' 7" from new forward perpendicular, 20° raked stem, and 16° half angle of entrance. Final characteristics of conversion: Length between perpendiculars = 440 ' IHP = 5000 horsepower Beam, molded = 56 .9' Speed = 15 knots Draft - 27.15' Range - 17,500 miles Displacement 14,175 tons Deadweight - 10,300 tons The conversion is considered feasible in spite of excessive fuel consumption, and would cost approximately One ana One Half to Two Million Dollars per ship. Recommendations for making this proposal an actuality: Self propulsion model test; necessary detail designs for contract plans., http://archive.org/details/aninvestigationo1094514342, U.S. Coast Guard (U.S.C.G.) authors.

Aurora Energy Resource's Michelin deposit is located in central Labrador, around 180 km northeast of Happy Valley-Goose Green. The project lies within the jurisdiction of the Nunatsiavut Government, whose 3-year moratorium on uranium mining is due to be reviewed in March 2011. In the interim Aurora proceeded with design work on a 10 000 t/d plant that would produce 97 000 000 lb uranium over the 17 year project life. The testwork and economic studies that preceded flowsheet design are summarised. The final layout selected includes SAG/ball milling, acid leaching with air/SO2 as an oxidant and resin-in-pulp extraction of the uranium. There is a table of major plant parameters with flowsheet., Aurora Energy Resource's Michelin deposit is located in central Labrador, around 180 km northeast of Happy Valley-Goose Green. The project lies within the jurisdiction of the Nunatsiavut Government, whose 3-year moratorium on uranium mining is due to be reviewed in March 2011. In the interim Aurora proceeded with design work on a 10 000 t/d plant that would produce 97 000 000 lb uranium over the 17 year project life. The testwork and economic studies that preceded flowsheet design are summarised. The final layout selected includes SAG/ball milling, acid leaching with air/SO2 as an oxidant and resin-in-pulp extraction of the uranium. There is a table of major plant parameters with flowsheet.

Contains fulltext : 80486.pdf (publisher's version ) (Closed access), A 50MHz array-based imaging system was used to obtain high-resolution images of the ear and auditory system. This previously described custom built imaging system (Brown et al. 2004a, 2004b; Brown and Lockwood 2005) is capable of 50 microm axial resolution, and lateral resolution varying from 80 microm to 130 microm over a 5.12 mm scan depth. The imaging system is based on a 2mm diameter, seven-element equal-area annular array, and a digital beamformer that uses high-speed field programmable gate arrays (FPGAs). The images produced by this system have shown far superior depth of field compared with commercially available single-element systems. Ex vivo, three-dimensional (3-D) images were obtained of human cadaveric tissues including the ossicles (stapes, incus, malleus) and the tympanic membrane. In addition, two-dimensional (2-D) images were obtained of an intact cochlea by imaging through the round window membrane. The basilar membrane inside the cochlea could clearly be visualized. These images demonstrate that high-frequency ultrasound imaging of the middle and inner ear can provide valuable diagnostic information using minimally invasive techniques that could potentially be implemented in vivo.

The retention of floating matter within the surf zone on a rip-channeled beach is examined with a combination of detailed field observations obtained during the Rip Current Experiment and a three-dimensional (3-D) wave and flow model. The acoustic Doppler current profiler–observed hourly vertical cross-shore velocity structure variability over a period of 3 days with normally incident swell is well reproduced by the computations, although the strong vertical attenuation of the subsurface rip current velocities at the most offshore location outside the surf zone in 4 m water depth is not well predicted. Corresponding mean alongshore velocities are less well predicted with errors on the order of 10 cm/s for the most offshore sensors. Model calculations of very low frequency motions (VLFs) with O(10) min timescales typically explain over 60% of the observed variability, both inside and outside of the surf zone. The model calculations also match the mean rip-current surface flow field inferred from GPS-equipped drifter trajectories. Seeding the surf zone with a large number of equally spaced virtual drifters, the computed instantaneous surface velocity fields are used to calculate the hourly drifter trajectories. Collecting the hourly drifter exits, good agreement with the observed surf zone retention is obtained provided that both Stokes drift and VLF motions are accounted for in the modeling of the computed drifter trajectories. Without Stokes drift, the estimated number of virtual drifter exits is O(80)%, almost an order of magnitude larger than the O(20)% of observed exits during the drifter deployments. Conversely, when excluding the VLF motions instead, the number of calculated drifter exits is less than 5%, thus significantly underestimating the number of observed exits., Hydraulic Engineering, Civil Engineering and Geosciences

Contains fulltext : 80486.pdf (publisher's version ) (Closed access), A 50MHz array-based imaging system was used to obtain high-resolution images of the ear and auditory system. This previously described custom built imaging system (Brown et al. 2004a, 2004b; Brown and Lockwood 2005) is capable of 50 microm axial resolution, and lateral resolution varying from 80 microm to 130 microm over a 5.12 mm scan depth. The imaging system is based on a 2mm diameter, seven-element equal-area annular array, and a digital beamformer that uses high-speed field programmable gate arrays (FPGAs). The images produced by this system have shown far superior depth of field compared with commercially available single-element systems. Ex vivo, three-dimensional (3-D) images were obtained of human cadaveric tissues including the ossicles (stapes, incus, malleus) and the tympanic membrane. In addition, two-dimensional (2-D) images were obtained of an intact cochlea by imaging through the round window membrane. The basilar membrane inside the cochlea could clearly be visualized. These images demonstrate that high-frequency ultrasound imaging of the middle and inner ear can provide valuable diagnostic information using minimally invasive techniques that could potentially be implemented in vivo.

Contains fulltext : 80486.pdf (publisher's version ) (Closed access), A 50MHz array-based imaging system was used to obtain high-resolution images of the ear and auditory system. This previously described custom built imaging system (Brown et al. 2004a, 2004b; Brown and Lockwood 2005) is capable of 50 microm axial resolution, and lateral resolution varying from 80 microm to 130 microm over a 5.12 mm scan depth. The imaging system is based on a 2mm diameter, seven-element equal-area annular array, and a digital beamformer that uses high-speed field programmable gate arrays (FPGAs). The images produced by this system have shown far superior depth of field compared with commercially available single-element systems. Ex vivo, three-dimensional (3-D) images were obtained of human cadaveric tissues including the ossicles (stapes, incus, malleus) and the tympanic membrane. In addition, two-dimensional (2-D) images were obtained of an intact cochlea by imaging through the round window membrane. The basilar membrane inside the cochlea could clearly be visualized. These images demonstrate that high-frequency ultrasound imaging of the middle and inner ear can provide valuable diagnostic information using minimally invasive techniques that could potentially be implemented in vivo.

The macrotidal intermediate-dissipative beaches of the southwest UK display strong seasonality whereby extensive low-tide bar/rip systems form during the spring season. These features reach a state of maximum development during the summer months, when strong rip currents are present at various stages of the tide that switch on/off due to tidal translation. This research investigates for the first time the circulation and dynamics of macrotidal rip systems from the perspective of the flow dynamics and surf zone circulation. A field experiment was conducted on a macro-tidal (range 6.3 m) with low-tide bar/rip morphology to quantify the circulation and dynamics of the rip current systems. Measurements of flow velocity, water depth and suspended sediment concentration were collected over the channel and shoal of transverse bar/rip system using an in-situ sensor arry, whilst the surf zone circulation patterns were monitored with post-processed GPS drifter floats. The in-situ data show that currents within the rip system are strongly correlated with the stage of the tide and maximum current speeds are recorded during the 3-hour period immediately around low water. During this period, wave breaking is maximised on the adjacent shoal resulting in a longshore gradient in wave dissipation. The GPS drifters indicate that an extensive rotational surf zone circulation pattern exists, whereby the offshore flow within the rip channel returns landwards over the intertidal bar from the outer edge of the surf zone.

The retention of floating matter within the surf zone on a rip-channeled beach is examined with a combination of detailed field observations obtained during the Rip Current Experiment and a three-dimensional (3-D) wave and flow model. The acoustic Doppler current profiler–observed hourly vertical cross-shore velocity structure variability over a period of 3 days with normally incident swell is well reproduced by the computations, although the strong vertical attenuation of the subsurface rip current velocities at the most offshore location outside the surf zone in 4 m water depth is not well predicted. Corresponding mean alongshore velocities are less well predicted with errors on the order of 10 cm/s for the most offshore sensors. Model calculations of very low frequency motions (VLFs) with O(10) min timescales typically explain over 60% of the observed variability, both inside and outside of the surf zone. The model calculations also match the mean rip-current surface flow field inferred from GPS-equipped drifter trajectories. Seeding the surf zone with a large number of equally spaced virtual drifters, the computed instantaneous surface velocity fields are used to calculate the hourly drifter trajectories. Collecting the hourly drifter exits, good agreement with the observed surf zone retention is obtained provided that both Stokes drift and VLF motions are accounted for in the modeling of the computed drifter trajectories. Without Stokes drift, the estimated number of virtual drifter exits is O(80)%, almost an order of magnitude larger than the O(20)% of observed exits during the drifter deployments. Conversely, when excluding the VLF motions instead, the number of calculated drifter exits is less than 5%, thus significantly underestimating the number of observed exits.

The retention of floating matter within the surf zone on a rip-channeled beach is examined with a combination of detailed field observations obtained during the Rip Current Experiment and a three-dimensional (3-D) wave and flow model. The acoustic Doppler current profiler–observed hourly vertical cross-shore velocity structure variability over a period of 3 days with normally incident swell is well reproduced by the computations, although the strong vertical attenuation of the subsurface rip current velocities at the most offshore location outside the surf zone in 4 m water depth is not well predicted. Corresponding mean alongshore velocities are less well predicted with errors on the order of 10 cm/s for the most offshore sensors. Model calculations of very low frequency motions (VLFs) with O(10) min timescales typically explain over 60% of the observed variability, both inside and outside of the surf zone. The model calculations also match the mean rip-current surface flow field inferred from GPS-equipped drifter trajectories. Seeding the surf zone with a large number of equally spaced virtual drifters, the computed instantaneous surface velocity fields are used to calculate the hourly drifter trajectories. Collecting the hourly drifter exits, good agreement with the observed surf zone retention is obtained provided that both Stokes drift and VLF motions are accounted for in the modeling of the computed drifter trajectories. Without Stokes drift, the estimated number of virtual drifter exits is O(80)%, almost an order of magnitude larger than the O(20)% of observed exits during the drifter deployments. Conversely, when excluding the VLF motions instead, the number of calculated drifter exits is less than 5%, thus significantly underestimating the number of observed exits., Hydraulic Engineering, Civil Engineering and Geosciences

Differential-cross-section data are presented for the 8Li(p, [alpha])5He reaction at 1.5 MeV center-of-mass energy, measured with a (radioactive) 8Li beam. The data are used to calculate one of the terms of the thermonuclear reaction rate for destruction of 8Li. In addition, other data are used to estimate the total reaction rate for p+8Li, which is found to be comparable to that used in previous calculations of abundances from primordial nucleosynthesis.

A beam of 7Be4+ ions having E = 20.7 MeV and intensity 1.5 x 104 s-1 has been produced via the 1H (10B, 7Be)4He reaction. The beam had an energy resolution of 1.0 MeV FWHM, 1 cm spot size, and 3[deg] angular divergence. The effect of a z-moveable secondary stop on beam purity was investigated. A 7Be4+ ion beam of E = 15.2 MeV, intensity 5 x 103 s-1, and similar energy resolution and emittance characteristics was produced via 12C(3He,7Be)8Be reaction. The maximum feasible 7Be secondary beams from these two reactions are extrapolated to be 5 x 105 s-1, respectively. Elastic scattering data for 7Be from Au and C targets are presented as an example of the use of this radioactive beam in secondary scattering experiments.

Hymnal containing 163 numbered hymns. Includes index. "Gospel pearls, edited and compiled for special use in the Sunday school, church, evangelistic meetings, conventions and all religious services by the Music Committee of the Sunday School Publishing Board" -- title page. "Printed in shaped notes" -- title page. Sections: Worship and devotion (no.1-no.75), Revival (no.76-no.143), Spirituals (no.144-no.163), Contents.

The object of this thesis is to present a conversion plan for the existing Liberty Ships involving least cost to increase their potential as a national defense investment by increasing their speed to 15 knots. Approximately 1500 Liberty Ships are now in the reserve fleet, costing originally upwards of Six Billion Dollars. They are regarded as obsolete and a questionable defense potential because of speed limitations .This proposal is based on the following: Scrap one ship and save propulsion machinery; modernize one ship by using the additional propulsion machinery obtained to double the power, and lengthen the bow 24 feet to improve resistance . Details of machinery changes : Move forward engine room bulkhead forward 17' 6" to make room for the two additional boilers; mount two main engines each 6' 6" from the centerline of the ship in the same longitudinal location with the starboard engine HP cylinder placed aft so that the engine driven auxiliaries and main condenser retain the same position relative to this main engine; install single reduction gears for engine speed of 76 RPM to 85 RPM of propeller; use new line and tail shafting, new stern tube, and new 18' propeller; necessary auxiliaries duplicated using those from scrapped ship. The new bow is faired into existing Station No. 3 at approximately frame 30 and has the following characteristics: Cut -up starting at 53' 7" from new forward perpendicular, 20° raked stem, and 16° half angle of entrance. Final characteristics of conversion: Length between perpendiculars = 440 ' IHP = 5000 horsepower Beam, molded = 56 .9' Speed = 15 knots Draft - 27.15' Range - 17,500 miles Displacement 14,175 tons Deadweight - 10,300 tons The conversion is considered feasible in spite of excessive fuel consumption, and would cost approximately One ana One Half to Two Million Dollars per ship. Recommendations for making this proposal an actuality: Self propulsion model test; necessary detail designs for contract plans.

The interfacial tensions were measured between molten sulphur and the aqueous solution, together with the contact angle made by molten sulphur on pentlandite, (Ni,Fe)9S8, surfaces. The molten sulphur/mineral work of adhesion was calculated and the effects of solution chemistry and surfactant addition determined. The results showed that the contact angle decreased significantly with temperature in the range 120-150 degrees C. The decrease in contact angle was reduced at 150 degrees C by the addition of 2 g/l of chloride ion as NaCl. Addition of 0.4 g/l of lignin sulphonates resulted in significantly greater contact angles at 150 degrees C. The presence of lignin sulphonates significantly reduced the work of adhesion between molten sulphur and pentlandite, and the performance of the surfactant was further enhanced in the presence of 8 g/l chloride ion. The results suggest that the surfactants may be equally effective should the process be commercialised., The interfacial tensions were measured between molten sulphur and the aqueous solution, together with the contact angle made by molten sulphur on pentlandite, (Ni,Fe)9S8, surfaces. The molten sulphur/mineral work of adhesion was calculated and the effects of solution chemistry and surfactant addition determined. The results showed that the contact angle decreased significantly with temperature in the range 120-150 degrees C. The decrease in contact angle was reduced at 150 degrees C by the addition of 2 g/l of chloride ion as NaCl. Addition of 0.4 g/l of lignin sulphonates resulted in significantly greater contact angles at 150 degrees C. The presence of lignin sulphonates significantly reduced the work of adhesion between molten sulphur and pentlandite, and the performance of the surfactant was further enhanced in the presence of 8 g/l chloride ion. The results suggest that the surfactants may be equally effective should the process be commercialised.

Osborne copper-gold mine in Queensland commenced hydraulic backfilling of three stopes in April 1999. Two of these stopes experienced barricade failure in July 1999 and January 2000. A comparison of the barricade designs with best practice showed that the Osborne fill system had more water to drain from a smaller area along longer paths, a lower quality of fill drainage properties and a larger face area for barricades of the same thickness. It was thought that damage from underground activities might also have reduced the ultimate strength of the barricades. The process for determining fill specifications and designing barricades was improved and design for a fill trial is almost complete. An issue highlighted by the review process was that the hydraulic fill system must be fully integrated with mine planning., Osborne copper-gold mine in Queensland commenced hydraulic backfilling of three stopes in April 1999. Two of these stopes experienced barricade failure in July 1999 and January 2000. A comparison of the barricade designs with best practice showed that the Osborne fill system had more water to drain from a smaller area along longer paths, a lower quality of fill drainage properties and a larger face area for barricades of the same thickness. It was thought that damage from underground activities might also have reduced the ultimate strength of the barricades. The process for determining fill specifications and designing barricades was improved and design for a fill trial is almost complete. An issue highlighted by the review process was that the hydraulic fill system must be fully integrated with mine planning.

Case studies are presented of three derelict sites in Kent and Essex that provide a good cross-section of opportunities for second-generation commercial uses of former chalk, limestone, clay and gravel workings. A 240 ha abandoned chalk quarry at Grays in Essex, now known as Chafford Hundred, is undergoing mixed development to include leisure facilities, a range of housing and commercial areas and an enhanced environment. The 120 ha of Stone Marshes now comprises the Crossways business park and the Dartford international ferry terminal. Reclamation and servicing required more work than had been anticipated and the fact that the area was within the green belt added to the delays, but Blue Circle was eventually able to provide a comprehensive development of the entire area to a high environmental standard. Stone Pit 1 landfill, at Dartford in Kent, is a former chalk quarry 40 ha in area and with an original average depth of 35 m. Landfilling commenced in 1976 and during the period 1979-1984 the site operator designed, developed and installed a gas collection and flaring system. From 1986 a gas plant supplied up to 5 000 000 therm/yr of landfill gas to a local cement works and in 1989 a 1 MW power generation scheme, later expanded to 3 MW, was commissioned. Gas is currently also supplied to a metal refining company for use in internal combustion engines., Case studies are presented of three derelict sites in Kent and Essex that provide a good cross-section of opportunities for second-generation commercial uses of former chalk, limestone, clay and gravel workings. A 240 ha abandoned chalk quarry at Grays in Essex, now known as Chafford Hundred, is undergoing mixed development to include leisure facilities, a range of housing and commercial areas and an enhanced environment. The 120 ha of Stone Marshes now comprises the Crossways business park and the Dartford international ferry terminal. Reclamation and servicing required more work than had been anticipated and the fact that the area was within the green belt added to the delays, but Blue Circle was eventually able to provide a comprehensive development of the entire area to a high environmental standard. Stone Pit 1 landfill, at Dartford in Kent, is a former chalk quarry 40 ha in area and with an original average depth of 35 m. Landfilling commenced in 1976 and during the period 1979-1984 the site operator designed, developed and installed a gas collection and flaring system. From 1986 a gas plant supplied up to 5 000 000 therm/yr of landfill gas to a local cement works and in 1989 a 1 MW power generation scheme, later expanded to 3 MW, was commissioned. Gas is currently also supplied to a metal refining company for use in internal combustion engines.