Lease Area Research Articles

Correction to: Effects of clam dredging on benthic ecology of two cultivated northern quahog beds with different harvest histories and sediment grain sizes

In Connecticut, cultivation of the northern quahog, or hard clam, Mercenaria mercenaria L., relies on hydraulic dredging. After harvesting, leased shellfish beds remain fallow for varying durations to facilitate natural reseeding and to allow small clams to reach harvestable size. The interval between dredging events, or harvest history, may influence benthic ecology and response of communities to further dredging. Two clam beds with different harvest histories, located near Milford, Connecticut, were studied from July through October 2012. These leased beds, fallowed for 3 and 8 years, respectively, were subdivided into two plots. One plot on each bed was commercially harvested in July while the other remained not dredged. Sediment sampling was conducted on alternate weeks using Smith MacIntyre grabs and sediment cores to compare ecology of benthic communities and chemistry of marine sediments on newly dredged and not dredged plots within leases. Main effects of lease (harvest history), dredging treatment (dredged versus not dredged plots), mean sediment phi size (ɸ), and season (sampling date) significantly affected benthic community structure. Newly settled bivalves, including early successional pioneer species, occurred in high abundance on 3-year beds. Diversity, evenness, and number of species were high on the 8-year beds, while abundance of individuals was low, more typical of later successional equilibrium communities. Differences among a subset of species on the 8-year beds were observed between dredged and not dredged plots while no community differences were observed between dredging treatments on 3-year beds. Significantly more individuals were observed on dredged versus not dredged plots on the 8-year beds only. Our results suggest that harvest frequency and/or sediment ɸ size may explain differences in benthic assemblages between leased areas with different dredging histories, while dredging had no measurable effect on sediment chemistry.

Management of plastic wastes at Brazilian ports and diagnosis of their generation

This study evaluated the management of plastic wastes at 20 Brazilian maritime ports, from three sources: vessels, leased and non-leased areas. The data were obtained from documents on port wastes organized in a relational database with defined protocols (closed form). Analysis of the spreadsheets prepared and field visits revealed that the main bottleneck in managing plastic wastes at ports is their segregation. In general, more material is segregated and sent for recycling from leased areas than non-leased ones (administered by the government). This relatively better performance in managing the wastes generated in leased areas is probably due to the need for private operators to comply with the international standards such as the Code of Environmental Practice to satisfy the international market.

Quantifying the recurring nature of fitout to assist LCA studies in office buildings

PurposeThe purpose of this paper is to quantify fitout churn in office buildings to more accurately evaluate the recurrent embodied energy in life cycle assessment studies.Design/methodology/approachThree research methods were used in the context of Central Business District (CBD) office buildings in Sydney. Method 1 involved leasing records from 528 office buildings; method 2, a leasing history from a selective sample of three prime grade office buildings; method 3, a targeted survey of 21 property professionals concerning fitout churn cycle estimates.FindingsPrime buildings are the area of most interest to fitout churn because they represent a large proportion of total office floor area. The churn rate differs according to office tenancy type (as defined by small, medium and large leased areas). Large tenants occupy the majority of floor space. Lease duration as obtained from Method 1, offers a reasonable proxy for predicting fitout churn. Using this method coupled with weighted-average calculations, the data indicate a fitout churn rate of 8.2 years.Research limitations/implicationsVariability concerning the situational context of Sydney CBD office buildings restricts broad generalisability of the findings. However, the research method used in this study would enable broad-based comparison and the potential for verification.Originality/valueThe main contribution of the research is to improve the ability to accurately predict fitout churn cycles as previous work only involves limited case studies and arbitrary estimates, thus lacking a strong evidence based.

Assessment of CO2 Levels Prior to Injection Across the Quest Sequestration Lease Area

The Quest Carbon Capture and Storage (CCS) project in Alberta, Canada, is a fully integrated project, as it involves the capture, transport, injection, storage of CO2, and a measurement, monitoring and verification (MMV) program. The MMV program has two key objectives: a) to ensure containment and b) to ensure conformance. Prior to the start of CO2 injection at the end of August 2015, a number of projects were undertaken to gather data from various domains, namely the atmosphere, biosphere, hydrosphere and geosphere, to provide input to the Quest MMV program. The focus of this paper is on monitoring activities undertaken in relation to the atmosphere and biosphere domains. Activities undertaken across the Quest sequestration lease area (SLA) included an eddy covariance system, soil gas probes, soil flux chambers, and walk-over surveys. In conclusion, understanding the spatial and temporal variability of CO2 levels prior to start of CO2 injection represents an important activity of a CCS MMV program. It provides technical input to the development of such a program, but also provides knowledge for communication to and awareness of project stakeholders (e.g. landowners) regarding CO2 levels within the atmosphere and biosphere across a SLA.

Implementation of a goal programming framework for production and dyke material planning

In oil sands mining, due to limitations in lease areas, the pit phase development and the construction of in-pit and ex-pit tailings containment dykes are carried out simultaneously. The primary research objectives are to formulate, implement and verify a theoretical optimisation framework based on Mixed Integer Linear Goal Programming (MILGP) formulations to simultaneously schedule production and dyke material. The numerical modelling approach used in implementing the framework is presented. A case study was compared with industry standard software, Whittle. In contrast, the MILGP model scheduled for more ore in the early years contributing to an increased net present value.

Bacterial community structure and functional potential in the northeastern Chukchi Sea

We performed a molecular microbial ecological analysis in the northeastern Chukchi Sea in order to characterize bacterial community structure and genetic potential for biogeochemical cycling and oil biodegradation in a region targeted for oil and gas exploration (Burger lease area). Samples were collected from the surface, middle (20m), and bottom (2–3m above seafloor) of the water column during the open-water season of August and September 2012 at 17 different locations. We determined bacterial community structure with 16S rRNA genes sequencing and detected functional genes, including an array of oil biodegradation and biogeochemical cycling (carbon, nitrogen and phosphorus cycling) genes, using the GeoChip 5.0 microarray, and then correlated molecular data to contextual physical and biogeochemical factors. Bacterial community structure differed significantly by depth (surface water vs. bottom water) and between sampling dates (August vs. September). While the relative abundance of major functional gene categories did not differ with depth, the abundance of individual functional genes for carbon cycling, nitrogen cycling, organic contaminant remediation, phosphorus cycling, sulfur cycling, virulence, and viruses differed between surface and bottom seawater samples. Aerobic oil degradation genes and taxa known to include oil-degrading bacteria were found at all three depths. These findings support previous observations that two different water masses contribute to a stratified water column in the summer open-water season of the Burger lease area, but indicate that potential function is fairly similar with depth despite differences in temperature, water chemistry, bacterial community structure, and individual functional gene alleles.

The need for sustainable technology diffusion in mining: Achieving the use of belt conveyor systems in the German hard-rock quarrying industry

Abstract The movement of raw materials can be one of the most challenging tasks in open pit mining, with truck transportation representing the largest factor in mining costs and resulting in major greenhouse gas (GHG) emissions. In this study, the transportation methods of bulk materials within German hard-rock open pit mines were investigated. Approximately 450 quarries were studied for their production tonnage, lease areas, mined rock type as well as mining methods and processing equipment. The results demonstrate that 90% of the operations use truck-based transportation methods, with the remainder relying partly or completely on continuous conveyor-based systems. The installation of continuous conveyors compared to trucks represents a real alternative because of reduced dead load, reduced GHG emissions and in many cases even reduced costs. Thus, for in-pit haulage in quarries sustainable technology substitutions exist that are yet to be adopted by the German quarrying industry. As this study shows, in the future the diffusion of sustainable technologies requires site champions and large-scale case studies that demonstrate their successful introduction in the mining value chain.

J-REIT所有オフィスにおけるCASBEE認証及び東京都トップレベル事業所認定が賃貸事業収益及び水道光熱費に与える影響

The purpose of this research is to evaluate the economic value of certification of green buildings based on j-reit (Japan Real Estate Investment Trust) owned office buildings. In the recent years, assessment systems for the environmental performance of buildings are being widely used in Japan. Some analyses were conducted in Japan to investigate whether green building certificates have a positive influence on the contract rent. However we need to investigate profits and expenses of the real estate rent to clearly explain the economic benefits of green buildings. In this research, we analyze the office building annual data in Japan which was disclosed by J-REIT. Operating benefits and utilities costs of 657 buildings in January 2014 － December 2014 was analyzed. Regarding the objective office, the total leased area is under 50000 m2 and each building was divided into green building certified or Non-certified. Subject green building certifications are Tokyo Top-Level Business Facility and CASBEE (Comprehensive Assessment System for Built Environment Efficiency). The net operating incomes of Top-Level Business Facility or CASBEE certified office buildings over 10000 m2 of total building area are bigger than that of not certified office buildings. The utilities costs of Top-Level Business Facility certified office buildings are the same as that of not certified office buildings, but the utilities cost of CASBEE certified office buildings is bigger than that of not certified office buildings. The net operating incomes of CASBEE certified office buildings over 3000 m2 and less than 10000 m2 of total building area are bigger than that of not certified office buildings. The utilities costs of CASBEE certified office buildings over 3000 m2 and less than 10000 m2 are the same as that of not certified office buildings. The net operating incomes of expired CASBEE certified office buildings over 10000 m2 of total building area are bigger than that of not certified office buildings. The utilities costs of expired CASBEE certified office buildings are the same as that of not certified office buildings. Using these results, the environmental performance of Top-Level Business Facility certified office buildings over 10000 m2 of total building area and expired CASBEE certified office buildings over 10000 m2 of the area, CASBEE certified office buildings over 3000 m2 and less than 10000 m2 of the area may be high in the value of the real estate. The utilities costs of buildings are not always related to the energy consumption, because an energy source, a type of contract and a contract fee are different in each building. In this survey, the primary energy consumption of CASBEE real estate buildings is correlated with the utilities cost of the buildings. The objective buildings do not install the regional air-conditioning.

Modeling Fertilizer Demand in Cotton-Producing Villages of Benin: Does Price Matter in a Centralized Distribution System?

Cotton is a strategic crop in Benin's economy and fertilizer is a crucial necessity for its development. Fertilizer supply is awkwardly cotton-oriented and depends totally on imports. Spurious liberalization, characterized by partial state withdrawal combined with a rigid distribution agreement between the state, fertilizer traders and farmers’ cooperatives, led to a drastic decline in fertilizer use and cotton production. Although fertilizer consumption resumed timidly with reforms, the supply system remained centralized (importers’ licensing, distribution quotas, price administration). This study inquired whether price is relevant in fertilizer demand in such a business environment. Randomly-selected 577 cotton farmers from purposively-chosen 191 cotton-producing villages, were interviewed about fertilizer use and distribution using structured questionnaires. Determinants of average villagelevel fertilizer demand, elicited using a multiple regression model with a joint agronomic and marketing perspective, included at 5% or 1% significance level: the region’s dummy, share of cotton in cultivated area, rural roads’ density, distance ‘village store - farmer’s fields, and off-farm income. Other non-negligible factors included: estimated cost price, soil degradation rate, diffusion rate of water and soil conservation techniques, proportion of leased land area and distance ‘farmer’s house - local agricultural market’. Despite an administered pan-territorial district-level price, fertilizer demand was still sensitive to the actual farm-gate prices. However, the business environment had a stronger influence. The policy levers to increase fertilizer use intensity include the development of road and market infrastructures, promotion of market orientation of farming and off-farm activities, wise liberalization of fertilizer retail market, and reform of the licensing system.

Close-proximity tidal phasing for ‘firm’ electricity supply

Tidal generation is highly predictable and thus an attractive renewable energy source to develop; however, output varies over short time scales. This can be mitigated through phasing of output between sites, as different locations have different timings of output. Phasing can be increased by geographical diversity; unfortunately areas with tidal resources suitable for generation are few, so the opportunity for this is limited.The Pentland Firth and Orkney Waters (PFOW) contain the World’s first leased sites for tidal stream generation. This paper focuses on close-proximity phasing between these leases and their ability to provide firm power, i.e. a guaranteed level of output. Results show phasing across individual leases and over the PFOW; combined output from all the lease areas exceeds 1% of nameplate capacity for 97.9% of the study, compared to 83.4%–94.5% for the individual leases. Relatively little storage makes significant levels of firm capacity obtainable; 255 MWh of storage means electricity demand of the two counties the developments fall within would be met ∼94% of the time.The methodology identifies lease suitability, high energy locations within leases, and quantifies the complementary characteristics of different tidal sites. This could inform strategic development of tidal sites, to maximise firm capacity.

Migration characteristics of long-tailed ducks (Clangula hyemalis) from the western Canadian Arctic

There are significant deposits of oil and gas in the Beaufort and Chukchi Seas, and many long-tailed ducks (Clangula hyemalis) spend a large portion of their annual cycle in that region, but little is known about their migration patterns. Consequently, we used satellite telemetry to track movements and reveal migration routes and staging areas of 57 long-tailed ducks from the western Canadian Arctic. After molting, all ducks moved westward along the Beaufort Sea coast of Canada and Alaska, into the Chukchi and Bering Seas and the North Pacific, staging at various locations. Long-tailed ducks wintered throughout the North Pacific region as far south as British Columbia, Canada on the North American side and Japan and South Korea on the Asian side, a distribution similar to long-tailed ducks marked with transmitters in Alaska. Spring migration of long-tailed ducks was generally a reversal of fall migration, following Alaskan and Asian coastlines north and eastward to breeding areas in Northwest Territories, Canada, with the exception of two females that travelled to Russia and one male and one female that stopped in northwestern Alaska for the breeding period. Migratory patterns of ducks from this study displayed both similarities and variations to other species breeding in the Arctic, e.g., eiders. However, similar to eiders, long-tailed ducks were in or near offshore oil and gas lease areas of the Beaufort and Chukchi Seas for significant portions of their annual life cycle, making them vulnerable to impacts from exploration and development in that region.

The Effects of Coal Seam Gas Infrastructure Development on Arable Land in Southern Queensland, Australia: Field Investigations and Modeling

<abstract> <b><sc>.</sc></b> The production of coal seam gas (CSG) in Australia is set to increase, driven by increasing global demand for energy and in response to the transition to a lower carbon economy through greater use of gas for electricity generation. Despite the many economic benefits delivered by the CSG industry, concerns have been raised over the potential environmental impacts associated with CSG production, particularly the long-term effects on the soil resource. Therefore, this work was conducted to: (1) assess the extent of damage to agricultural soil caused by the various elements of CSG development and (2) estimate the likely impact of soil compaction, caused during establishment of CSG infrastructure, on crop productivity. The study was undertaken using a paired-sites approach by comparing measurements conducted on selected soil properties in areas around and including well-head sites with measurements in neighboring agricultural fields. These spatial areas are referred to as “lease” and “field” areas, respectively. Measurements were used to guide parameterization and application of the Agricultural Production Systems Simulator (APSIM) model to assess the likely effects of changed soil conditions on crop productivity. To achieve this, the APSIM model was used to simulate wheat ( L.) yields for 115 years on Grey Vertosols in the Darling Downs region of Queensland. Simulations were conducted with soil properties representing: (1) field area conditions not affected by CSG activities, (2) lease area conditions in which soil had been impacted by CSG activities during the development phase, and (3) lease area conditions where soils had been rehabilitated. Results showed that soil compaction within lease areas in the top 300 mm of the profile was approximately 15% higher compared with field areas (p < 0.05). The modeling work suggested that near-surface (0 to 300 mm depth) soil compaction within affected areas can lead to significant losses in crop productivity due to adverse effects on soil hydraulic properties. The simulation analyses predicted a 53% reduction in median wheat yields compared with simulated results in neighboring agricultural fields. For the bottom and top deciles, predicted relative yields were up to 60% and 32% lower, respectively. Practical solutions for management of such compaction are presented and discussed. Soil cultivation of the top 300 to 350 mm will ensure sufficient soil water storage in most years, thereby reducing the risk of crop failure. Progressive soil loosening techniques for alleviation of deeper compaction were reviewed; however, their cost-effectiveness under Australian soil conditions requires further investigation. Limit bulk density values of 1.45 and 1.60 g cm^-3 for the 0 to 350 mm and 350 to 700 mm depth intervals, respectively, are suggested as references for CSG-rehabilitated soil. These critical values may be used as guidance until further studies are undertaken. The assessment of soil chemical properties indicated that these were affected to a lesser extent by the establishment of CSG infrastructure. However, a general requirement is careful manipulation of sodium-rich subsoil and avoidance of soil blending during reinstatement operations. The dataset acquired and the simulation approach employed in this study can be used to further develop soil management guidelines relevant to the Australian CSG industry. Cost-benefit analyses of soil management practices for reinstatement, development of soil quality standards, and industry best management practices are required.

Porosity controls on secondary recovery at the Loudon field, south-central Illinois

Waterflooding has been used as an effective means to enhance oil recovery in mature oil fields for decades. The success of waterflooding is a function of geology, facies changes, and fluid dynamics, specifically, formation porosity and permeability. Within the Loudon oil field (Illinois), waterflooding has been used to increase production, but the degree of success has been variable. We have used 3D facies modeling was evaluate the variables controlling the success or failure of waterflooding. Three leases within the Loudon field exhibiting varying degrees of waterflood success were investigated. The K. Stubblefield lease, with the highest mean porosity of 13.5%, responded most favorably to waterflooding, with an increase of more than [Formula: see text]. Thick, high-porosity zones are well connected within the lease area, contributing to greater communication among the injection wells and the producing wells. The Rhodes-Williams lease, with porosity of 11.5%, had an increase in production of [Formula: see text]. The model showed that within this lease area, high-porosity zones were either orientated in directions that provided flow away from production wells or were lower porosity zones that finger with higher porosity zones restricting flow. The George Durbin lease, with porosity of 11.5%, produced only an additional [Formula: see text]. The model suggests that injector wells may be positioned in low-porosity zones and, as with the Rhodes-Williams lease, the alignment and distribution of the low porosities inhibit recovery within the producing wells. The 3D models indicated that although porosity plays an important role in the success of waterflooding, the alignment and distribution of the high- and low-porosity zones play a greater role in the success of secondary recovery techniques. Our research also demonstrated the utility and workflow of digitizing older paper well logs to incorporate into modern modeling software.

FEATURES OF TEMPESTITES FORMATION IN SEDIMENTS OF THE VIKULOV SERIES

A review of the genetic conditions of tempestites formation is made. It is shown that in the Vikulov series rocks the records of the storm influence are identified. The sedimentation settings are described in detail in which the productive deposits of the Vikulov series formed within the lease area Em-Egovski.

Transience and persistence of natural hydrocarbon seepage in Mississippi Canyon, Gulf of Mexico

Analysis of the magnitude of oil discharged from natural hydrocarbon seeps can improve understanding of the carbon cycle and the Gulf of Mexico (GOM) ecosystem. With use of a large archive of remote sensing data, in combination with geophysical and multibeam data, we identified, mapped, and characterized natural hydrocarbon seeps in the Macondo prospect region near the wreck site of the drill-rig Deepwater Horizon (DWH). Satellite image processing and the cluster analysis revealed locations of previously undetected seep zones. Including duplicate detections, a total of 562 individual gas plumes were also observed in multibeam surveys. In total, SAR imagery confirmed 52 oil-producing seep zones in the study area. In almost all cases gas plumes were associated with oil-producing seep zones. The cluster of seeps in the vicinity of lease block MC302 appeared to host the most persistent and prolific oil vents. Oil slicks and gas plumes observed over the DWH site were consistent with discharges of residual oil from the wreckage. In contrast with highly persistent oil seeps observed in the Green Canyon and Garden Banks lease areas, the seeps in the vicinity of Macondo Prospect were intermittent. The difference in the number of seeps and the quantity of surface oil detected in Green Canyon was almost two orders of magnitude greater than in Mississippi Canyon.

Методы функционально-стоимостного анализа в стратегическом планировании развития лесного хозяйства в современных условиях

Federal Law № 172-FZ &amp;#34;On the strategic planning in the Russian Federation&amp;#34; envisages the creation of a unified system of state strategic planning. Effective functioning of the system, includ-ing in the field of forest relations, is especially actual in times of economic crisis and federal budget deficit, when priority is to determine the priorities of the industry. For this purpose, the use of the method of value analysis is proposed to justify the choice of the most significant events of the state program &amp;#34;Development of Forestry&amp;#34; for the period of 2013-2020, its indicators. Differentiation is made on the performance of the first order (priority indicators - woody territory of the Russian Fed-eration, the amount of payments to the budget of the Russian Federation on the use of forests, the ratio of the actual amount of timber to set the allowable volume of wood removals); as well as indi-cators of the second and third orders, directly affecting the achievement of the three priority indica-tors. A mechanism is proposed to optimize the costs of priority forest management activities through increased funding through internal reallocation of resources within the state program. For example, increasing the &amp;#34;investment&amp;#34; attractiveness of forest areas for potential tenants can be achieved in the following way: an increase in funding for forest management will provide additional updating on state forest areas, which will increase the area of leased forest areas. In this way it is possible to achieve cost of saving from the federal budget for forest management activities on the forest plot (performed at the expense of the tenant) and - an increase in revenues in the fiscal system of the country. In order to justify the cost of the planned work in determining resource support activities of the state program it is recommended to create a unified system of standard costs for forestry works and services.

Mapping of groundwater potential zones in Salem Chalk Hills, Tamil Nadu, India, using remote sensing and GIS techniques.

This study proposes to introduce the remote sensing and geographic information system (GIS) techniques in mapping the groundwater potential zones. Remote sensing and GIS techniques have been used to map the groundwater potential zones in Salem Chalk Hills, Tamil Nadu, India. Charnockites and fissile hornblende biotite gneiss are the major rock types in this region. Dunites and peridodites are the ultramafic rocks which cut across the foliation planes of the gneisses and are highly weathered. It comprises magnesite and chromite deposits which are excavated by five mining companies by adopting bench mining. The thickness of weathered and fracture zone varies from 2.2 to 50 m in gneissic formation and 5.8 to 55 m in charnockite. At the contacts of gneiss and charnockite, the thickness ranges from 9.0 to 90.8 m favoring good groundwater potential. The mine lease area is underlined by fractured and sheared hornblende biotite gneiss where groundwater potential is good. Water catchment tanks in this area of 5 km radius are small to moderate in size and are only seasonal. They remain dry during summer seasons. As perennial water resources are remote, the domestic and agricultural activities in this region depend mainly upon the groundwater resources. The mines are located in gently slope area, and accumulation of water is not observed except in mine pits even during the monsoon period. Therefore, it is essential to map the groundwater potential zones for proper management of the aquifer system. Satellite imageries were also used to extract lineaments, hydrogeomorphic landforms, drainage patterns, and land use, which are the major controlling factors for the occurrence of groundwater. Various thematic layers pertaining to groundwater existence such as geology, geomorphology, land use/land cover, lineament, lineament density, drainage, drainage density, slope, and soil were generated using GIS tools. By integrating all the above thematic layers based on the ranks and weightages, eventually groundwater potential zones were demarcated. The study indicates that groundwater potential is good to high in 22 villages and moderate in 13 villages. The good to high potential zone occupies an area of 128 km2 and moderate potential zone occupies an area of 77 km2. Groundwater occurrence is poor in five villages which need artificial recharge to augment groundwater.

The impact of invasive tunicates on the demand for phytoplankton in longline mussel farms

Abstract Mussels (Mytilus edulis) cultivated on the eastern coast of Prince Edward Island (PEI), Canada, must compete for food resources with three invasive tunicates (Botrylloides violaceus, Ciona intestinalis and Styela clava). Clearance rates determined for each species were used to calculate clearance rate per unit lease area (CRArea) for various fouling scenarios. CRArea for mussels alone was estimated at 338 ± 20 l h− 1 m− 2. Surprisingly, the size of the mussels under cultivation had no significant effect on estimates of CRArea, due to self-thinning processes that gradually eliminated 89% of the seed mussels over the 2-year production cycle. CRArea was also unaffected by the presence of the fouling colonial tunicate B. violaceus. In contrast, the presence of the solitary tunicate C. intestinalis or S. clava significantly increased CRArea by 30–47% compared to non-infested scenarios, even with control/treatment measures in effect. Size fractionation of the available phytoplankton resources indicated that picophytoplankton (0.2–3.0 μm) accounted for a major proportion of the primary production (61.5 ± 4.0%) and standing stock biomass (75.8 ± 3.6%). M. edulis was much less efficient at retaining this picophytoplankton component (18.1 ± 2.2%) than were the invasive tunicates (59.0 ± 2.6%). Carrying capacity calculations indicated a balanced state of demand versus supply for nanophytoplankton (> 3.0 μm) when mussel leases occupy 33% of the spatial area of a bay. The presence of solitary tunicates effectively lowered this bay-scale occupancy threshold to 23–26% (treated sleeves) or 10–11% (non-treated sleeves).

Geophysical Characterization of Salinity Ingress in Surka Mining Lease Area of Gujarat, India

Salinity ingress is refers to the process of salt water invading areas which previously contained only fresh water. The coastal areas of Gujarat especially the villages lying within 20-25 km from the seashore are suffering from the problem of salinity ingress. Most of the rivulets that drain this region are seasonal at best and their water does not last beyond monsoons. The other aquifers like ponds, which get water from these rivers, also dry up as early as October. The present paper deals with the salinity ingress of Surka mining lease area of Gujarat.

Importance of Radius of Influence and its Estimation in a Limestone Quarry

Limestone mining at Lanjiberna limestone and dolomite quarry has created positive as well negative impacts on ground water. With further deepening of the mine, drawdown trend (negative effect) is observed and at the same time ground water recharge of the order of 4,527.48 m3/day, through mine pits (positive impact) is noticed. The aquifer present in the area is unconfined and mainly consists of weathered quartzite, phyllites, limestone and dolomite. To know the cumulative impact of mining on surroundings, the effective radius of influence (Re) for excavated mine area is calculated as 1,059 m. Here, it may be noted that three ‘concentric working pits’ (Pit No. 2 & 6; Pit no 1 & 3 and Pit No 4 & 5) produces limestone at this mine and the pit-wise radius of influence (Ro) is estimated. Value of Ro for Pit-2 & 6 is 612.14 m; Pit-1 & 3 is 475 m and Pit-4 & 5 is 384.15 m. Its average i.e., Ro (for all three pits, cumulative) is estimated as 490 m. From this typical case study and estimation of Ro and Re values, it is concluded that the maximum and minimum value of overall impact/influence lies in between 0.49 and 1.05 km. These estimated values of ‘area of influence’ are less compared to the whole mine lease area values. Local aquifer, which lies at shallower as well as at deeper depth had behaved consistently with respect to recharge and drawdown conditions. Thus, assessment of Ro and Re is extremely helpful for ‘integrated mine planning’ to achieve targeted production, economically with minimum interruptions.