Title of Invention	METHOD OF DETERMINING THE SUSTANIBILITY PERIOD OF STOCKPILED MINED SOIL FOR PLANT GROWH IN MINING AREA
Abstract	The method of determining the period of sustainability of stockpiled mined soil for plant growth in mining areas comprising the steps of measurement of soil properties such as texture, pore space, field moisture, field capacity, water holding capacity (WHC), wilting capacity, pH, electrical conductivity (EC), cation exchange capacity (CEC), Ca, Mg, Na, K, sodium absorption ratio (SAR), organic carbon (OC), phosphorous, microbial population required for plant growth on different aged stockpiled mined soil dumps and unmined land of similar geographical conditions, analysis of the deterioration of soil properties stockpiled mined soil with respect to time and finally determining the said period of sustainability as the time period till which the soil have the soil properties required plant growth as in case of mined soil of similar conditions.

Title of Invention

METHOD OF DETERMINING THE SUSTANIBILITY PERIOD OF STOCKPILED MINED SOIL FOR PLANT GROWH IN MINING AREA

Abstract

The method of determining the period of sustainability of stockpiled mined soil for plant growth in mining areas comprising the steps of measurement of soil properties such as texture, pore space, field moisture, field capacity, water holding capacity (WHC), wilting capacity, pH, electrical conductivity (EC), cation exchange capacity (CEC), Ca, Mg, Na, K, sodium absorption ratio (SAR), organic carbon (OC), phosphorous, microbial population required for plant growth on different aged stockpiled mined soil dumps and unmined land of similar geographical conditions, analysis of the deterioration of soil properties stockpiled mined soil with respect to time and finally determining the said period of sustainability as the time period till which the soil have the soil properties required plant growth as in case of mined soil of similar conditions.

Full Text	1.0 Field of invention This invention relates to a noble method of determining the sustainability period of stockpiled soil for suitable plant growth without biological reclamation. 2.0 Back ground of the invention Opencast mining is progressively increasing in India"s coal production. In the process of opencast mining, the area is completely stripped of vegetation to remove the overburden covering the coal seam. There are several changes occur in the physical, chemical and microbiological properties of soils as a result of storage. Some caused by the actual construction of the store rather than during the course of storage. By for the greatest impact of mining on the nation"s soil resources is due to opencast mining, which is having a very much potential for the deterioration of soil quality than underground operations. The following qualitative losses suffered by dug topsoil over time: i) Complete loss of profile due to mixing of soil horizons, ii) Dominance of sand particles indicating low stability of aggregates, iii) Decrease of the silt and clay fraction due to increased erosion, iv) Increase of bulk density and pore spaces arising out of the use of earth moving heavy machineries. As a result gaseous diffusion becomes more difficult and restricts growth of deep-rooted plants. v) Decrease of moisture retention properties due to changes of topography, vi) Increase in wilting capacity indicates the deficiency of plant growth materials, vii) Increased acidity due to leaching of basic cations and increase of soluble salts due to the mixing of lower soil horizons, viii) Decrease in cation exchange capacity (CEC) owing to the presence of low content of organic matter and decrease of clay percent, ix) Increase in organic carbon and total nitrogen probably due to low humification due to the lack if soil micro flora. x) Increase in C/N ratio due to lack of microbial decomposition, xi) Reduction in fertility status (NPK) due to maximum leaching and mixing of soil horizons. xii) Increase of the concentration of available (Diethylenetriamine pentacetic acid i.e.DTPA extractable) iron and manganese due to increase of acidity. xiii) Reduction in soil microbes due to the presence of low concentration of organic carbon, moisture and other edaphic factors. xiv) Reduction in native seed species due to degradation of soil characteristics. Mineral extraction process must ensure the return of the productivity of the affected land. With the rising environmentalism concurrent post-mining reclamation of the degraded land has become integrated feature of the whole mining spectrum. Conservation and reclamation efforts to ensure continued beneficial use of land resources are essential. Opencast mining severely disturbs land in and around mining areas. It is reported that every million tonne of coal extracted by surface mining methods damage a surface area of about 4 ha in India. The coal industry alone accounts for rendering biologically unproductive area of about 500 ha a year during 1994-95, which rose to 1400 ha a year by 2000 AD. The topsoil must be mined separately at the beginning of the mining operation. This is particularly necessary in coal mining areas due to the scarcity of soil in the coalfields. Five years or more may pass between the removal of topsoil and its replacement over the reclaimed area. During this time the soils are found to become biologically sterile, and its nutrient value are found to be lost completely The US Department of Interior regulations require that topsoil should be removed in a separate layer from the areas to be disturbed. The main environmental factors inhabiting the plant growth in soil dumps are instability, unknown steep slopes, high levels of toxic elements, wind erosion and low nutrient status and absence of soil microorganism and soil fauna. Stockpiling of soil materials has been found to degrade the soil quality by decreasing the organic matter content, disrupting nutrient cycles and increasing the bulk density. Areas damaged by mining depend on seam thickness, stripping ratio and quarry depth. Direct damage to land takes place due to excavation and creation of overburden, mineral dumps, civil structures, roads and colonies. Indirect damage takes place due to water pollution, hydrological disturbance, silting and run off. Opencast mining also leads to rapid erosion of land because of slope stability problems and sometimes it may cause landslides. Land degradation may result in soil erosion leading to the destruction of watersheds, siltation and loss of valuable fertile soil. To combat these situation a fact finding survey is essential 3.0 Drawback associated with the known art Topsoil is an essential component in abandoned mines for growth of vegetation and has to be preserved for post-mining land reclamation. It is seriously damaged if it is not mined out separately in the beginning with view to replacement of for reclamation of the area. It is necessary to save topsoil for latter use in a manner to protect the primary root medium from the contamination and erosion, hence its productivity. Systematic handling and storage practice can protect the properties of topsoil while in storage and also when it has been redistributed on to the regarded areas. It should be noted that the period between the initial removal of the topsoil and final laying of the same over the reclamated area might be a long time lapse. So the properties of stockpiled soil deteriorate and become biologically unproductive. The issue is the preservation of topsoil (stockpiling) in such a manner as to protect its productivity for later use in restoration of mined land. This problem is very much acute in India and a vast mined out areas are continually being biologically sterile every year. Reclamation of degraded land has become a great challenge to Indian coal mining industry. Efforts to grow vegetation on overburden dumps and degraded mined lands as a part of biological reclamation are not being successful. The reasons are not completely understood and no work in this line has yet been reported As this soil is to be utilized for the reclamation of degraded mined land it is essential to search out the reasons of mined out areas of being biologically unproductive 4.0 Object of invention The method of determining the period of sustainability of stockpiled mined soil for plant growth in mining areas specifically in open cast mining areas. 5.0 A summary of invention Thus according to the present invention there is provided a method of determining the period of sustainability of stockpiled soil for plant growth in mining areas comprising the steps of measurement of soil properties required for plant growth on different aged stockpiled mine soil dumps and unmined land of similar geographical conditions. analysis of the deterioration of soil properties stockpiled mine soil with respect to time determining the said period of sustainability as the time period till which the soil have the soil properties required plant growth as in case of mined soil of similar conditions. As this soil is to be utilized for the reclamation of degraded mined land it is essential to determine the the period of sustainability of stockpiled. No systematic study has been reported to determine shelf life period. It has been observed that prolonged stockpiling implies continual loss of fertility, which ultimately leads to biological sterility. Almost in every mineral-bearing zone mining and land degradation have been inseparably connected. Irrespective of the scheme of exploitation, mining may be expected to affect the environment and ecology of the region. By far the greatest impact of mining on India"s soil resources with opencast mining having a greater potential for the deterioration of soil quality than underground operations. In the process of opencast mining the area is completely stripped of vegetation to remove the overburden covering the coal seam. There are several changes in the physical, chemical and microbiological properties of soils as a result of storage, some caused by the actual construction of the storage rather than during the course of storage. Topsoil is an essential component of land reclamation in mining areas. The topsoil is very seriously damaged if it is not mined out separately in the beginning with a view for replacement for due reclamation of the area. This is particularly necessary to save topsoil for a later use in a manner to protect the primary root medium from contamination and erosion and hence its productivity. It has been indicated, however, that systematic handling and storage practices can protect physical and chemical characteristics of topsoil while in storage and also after it has been redistributed onto the regarded area. Monitoring and implementation of these steps in accordance with site-specific modern technology will minimize the deterioration and provide a medium for plant growth. Topsoil is very useful in abandoned mines for the growth of vegetation. It is extremely required for post mining land reclamation. It is to be excavated separately and stockpiled when it becomes impractical to redistribute immediately. Efforts to grow vegetation on overburden dumps and degraded mined lands as a part of biological reclamation are not being successful in India. The reasons were not completely understood. . It is claimed that if the shelf life period of soil in a particular area is determined, mining authority can decide whether it becomes essential to go for cost intensive biological reclamation or they can preserve the mined soil by technical reclamation only. This ensures the saving time as well as money. A prior knowledge of topsoil shelf life periods would enable the mine planner to draw up an appropriate strategy for topsoil excavation vis-a-vis mine scheduling. An appropriate concurrent and post mining reclamation strategy can also be chalked out. By determining the deterioration of physical, chemical and microbiological properties in different aged soil dumps the shelf life period can be ascertained. Shelf life period indicates whether biological reclamation is required for the stockpiled topsoil. Biological reclamation must be adopted to preserve the topsoil if the storage period exceeds the shelf life period. If the shelf life period of topsoil in a particular area is determined, the mining authority can decide whether it is essential to choose biological reclamation for the preservation of topsoil or whether they can preserve the soil by technical reclamation only. A prior knowledge of topsoil shelf life period would enable mine planners to draw up an appropriate strategy for topsoil excavation vis-a-vis mine scheduling. An appropriate concurrent and post mining reclamation strategy can also be determined. This will not only save time but also save money. Another important aspect of this invention is the shortening of time frame for the determination of shelf life period. Generally such a study would require 10 years time to determine the shelf period in a particular area. But an innovative approach has been developed, which requires only 5-6 months time for the study for the determination of the said shelf life. The techniques adopted for achieving the target are given below: • The shelf life period in a particular area depends on climatic conditions, soil characteristics and site-specific factors. It will vary from area to area. To determine the shelf life period in a particular area one opencast coal mine (working) is to be investigated. • Unmined areas surrounding the working mine are to be investigated for the generation of base line data of unmined soil and they are to be compared with those of mined soil to determine the deterioration of soil quality due to mining. • From the different aged soil dumps (1 to 10 years) and from the unmined land of similar soil type soil samples are to be collected. • Approach for the selection of soil sampling locations in virgin areas as well as from the dumps, method of sampling, sample preparation, parameters to be considered determination of soil quality, method of determination are given in the Data collection methods section (Section 6.2). • Representative soil samples are to be collected from different spots taken from a uniform depth and of the same approximate volume, which are distributed at random covering each sampling unit and twelve number of composite samples are to be prepared • Field tests and laboratory tests are to be conducted to generate the base line data for the unmined land and for different aged soil dumps with respect to physical and water retention properties, physico-chemical and ion-exchange properties, available macro and micro nutrients and microbial population and the base line data of the unmined land and different aged soil dumps are to be determined. • Profile characteristics of the soil, soil physical properties, infiltration rate, water retention properties, available macronutrients, micronutrients and microbial status of soil are to be studied. The properties of the unmined soil are to be compared with those of the different aged soil dumps and the deterioration of the soil properties with respect to time is to be determined. • The graphical representation of the deterioration of soil organic carbon, nitrogen, phosphorous, potassium are to be plotted and the data results are to be examined to determine the quantitative losses of soil properties with respect to time till sterility • From the deterioration of soil physical, chemical and microbiological properties in different aged dumps till sterility shelf life period is to be determined.. 6.0 Detailed description of the invention 6.1 Description of the study area One large opencast coal project was investigated for the determination of shelf life period. The opencast project was the largest project of Eastern Coalfields Limited (ECL) located in the Godda District of Jharkhand. It is situated between latitudes 24 °58"39" and 25°1"37" N and longitudes 87°20"32" and 87 °23"58" E. The mining started in the year 1980. Target production of coal is lOMt/y. The total volume of overburden has been worked out as 985.15 Mm3. The life of the project is 71 years. The mineable reserve is 430.43 Mt.. The surface of excavation is about 15 sq. km. The total land requirement for the project is 2177 ha out of which 1873.81 ha is agricultural land, 113.05 ha "danga" (cultivable waste) land and 110.56 ha forest land .Land to be affected by direct mining will about 67% (quarry only) . The region was mostly agricultural land (1874 ha) with a small area of wasteland (113 ha), reserved forest and sharb forest (110 ha) he agricultural activities depend on ponds and rains. The major crops cultivated in the region were paddy (Oryza sativa), sugar cane {Sacchurm officimarum) gram (Cicer arietimum). The most important aspect of the invention 17 different parameters of a specific soil samples wherein mining is done are measures. Those parameters are texture, pore space, field moisture, field capacity, water holding capacity (WHC), wilting capacity, pH, electrical conductivity(EC), cation exchange capacity (CEC), Ca,Mg,Na, K, sodium absorption ratio (SAR), organic carbon (OC), phosphorous, microbial population. 6.2 Data collection methods Determination of shelf life period includes various field tests and laboratory tests. Soil samples were collected from the unmined land in and around the project areas. Ten numbers of sub samples were collected from spots, which were distributed at random covering each sampling unit. Each sub sample was taken to a uniform depth and of the same approximate volume. Twelve numbers of composite soil samples were prepared. The depth of the topsoil varied from 15 to 22cm in the area. They were striped and stockpiled separately. Soil samples were also collected from six different age classes (1,3,4,6,9 and 10 years old) of mine soil dumps around the working coal mine of the opencast project, which were not vegetated.. Eight samples were collected from each dump. The sampling location sites were randomized after site facing. The mine soil dumps were having moderate to steep slope ranging in height 7 to 8 m. After the collection, soil samples were air dried at room temperature and lightly crushed with mortar pastels and passed through 2mm sieve for analysis. Infiltration rates were measured by cylinder infiltrometer method. Field capacity and bulk density were measured according to standard method. The water holding capacity (WHC) and moisture content of the soils were measured by gravimetric methods. Soil pH, electrical conductivity (EC), organic carbon, available nitrogen, phosphorous and potassium were determined. The wilting coefficient was measured by plant method; cation exchange capacity (CEC) and exchangeable cations were also determined by neutral normal ammonium acetate method. The available micronutrient cations, i.e. iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn), were extracted with diethylene- triamine penta acetic acid /calcium chloride (DTPA-Cl2) solution and analyzed by atomic absorption spectrophtometry. 6.3 Data results The soil profile of unmined soil was found to be grayish in color, sub angular blocky structure, sticky and plastic with gradual smooth boundary. In different aged soil dumps these were found to be light grayish brown in color, single green structure, nonsticky and non-plastic and having many vertical tubular pores. Infiltration rates (IRs.) for unmined areas were found to be 3.12 to 0.7cm h4 After 240 min, the average IRS was 0.6cm h"1. The physical and water retention properties of unmined soil and different aged soil dumps are given in Table I. Average values for the particle size distribution were 61.2% (sand) 27.7%(Silt) as 11.1% (Clay), respectively. The bulk density of unmined soil was found to be 1.39 Mg/t. The bulk densities of soil dumps gradually increased from 1.66 Mgmt for one-year-old dumps to 1.72 Mgm3 for ten-year-old dumps. The mean value of pore space of unmined soil was found to be 47.2% for the soil dump this varied from 37.4% for a one year old dump to 35.1% for a ten year old dump. The field moisture, maximum water holding capacity % wilting capacity found to decrease along with the increase of age of the dumps. Values in parentheses represent range In unmined soil the pH value was found to be 6.38 but it was found to be decreased gradually and at 10th year it was more acidic ( was 0.24 ds m-1 and varied for 0.36 dsm-1 (1st year) to 0.26 dsm-1 (10th year). The cation exchange capacity of the unmined soil was found to have a mean value of 11.8 cm ol (P+) Kg -1. In the soil dumps this value decreased gradually from 9.61 to 7.41 cmol (P+) Kg-1 with the increase of age. Exchangeable Ca, Mg, Na, and K levels were also found to be lower than those in unmined soils. The sodium adsorption ratio (SAR) in unmined soil was 0.14 and it was varied between 0.12 and 0.15 in soil dumps. The percentage base saturation in unmined soil was found to be 76.0% and gradually decreased as the age of the soil dumps increased from 74.3 to 56.1%. 6.4 A brief description of the accompanying drawings Figure 1: Variation of organic carbon in different aged soil dumps and unmined soil Figure 2: variation of available nitrogen in different aged soil dumps and unmined soil Figure 3: Variation of available phosphorous in different aged soil dumps and unmined soil Figure 4: Variation of available potassium in different aged dumps and unmined soil Figure 5: Variation of microbial population in different aged soil dumps. The variation in the organic carbon (c) content in soil dumps and unmined soils is shown in Figure. 1. The organic carbon content in unmined soil was 0.72% and the soil dumps were found to be very poor and varied from 0.38 to 0.26%. The organic carbon content levels in unmined soil decreased markedly with storage to about 47% levels in the 1-year-old dumps, about 23% in the 1-6 year-old dumps and about 6% in 6-10 year old dumps. From Table 3 it will be seen that the mean value of available NPK in unmined soils were 221.0 kg ha-1, 8.4 Kg ha-1 and 223.6 hg ha -1 respectively .The variation in available nitrogen (N), phosphorous (P) and potassium (K) in different aged soil dumps and unmined soils are shown in Figures.2, .3 and .4, respectively. In soil dumps NPK values were found to decrease with increasing age of the soil dumps over the ranges 151.7 to 112.5 Kg ha-1, 6.5 to 5.5 Kg ha-1 and 162.0 to 121.2 kg ha,-1 respectively. In unmined soils the available Fe was found to be 28.9 mgKg- 1, Mn 18.6 mg Kg-1, Cu 0.7 mg Kg-1 and Zn 0.53 mg Kg -1. The available Fe, Mn, Cu and Zn in soil dumps showed no consistent trends with the increasing age of soil dumps. The microbial population in soil dumps decreased sharply in comparison to unmined soil. In the one year aged dump, the population of bacteria, actinomycetes and fungi were found to be 5 to 8 times lower. There was a gradual decrease in population of bacteria, actimycetes and fungi from 1 to 10 year- aged dumps (Figure. 5) and at the 10th year these were 44%, 60% and 76%, respectively. The decrease was statistically significant. The clay content and the field moisture content showed strong and significant positive correlation with field capacity, water holding capacity and wilting coefficient at 1-% level (Table 4). Very high positive correlation coefficient was also observed among organic, available nitrogen and available phosphorous, while available potassium did not show strong correlation with other parameters (Table 5). Changes in microbial numbers due to the increased age of soil dumps showed a continuous decrease every year and at the end of the 6th year the number decreased to a minimum level. (Table 6). F.M. = Field moisture; O. C. = Organic Carbon; B = Bacteria; A = Actinomycetes; F= Fungi 6.5 Determination of shelf life period Particle size analysis revealed that sand particles increased, silt and clay particles decreased, with respect to unmined soil. This trend may be because of increased erosion. Dominance of sand particles indicated low stability of aggregates and consequently a high rate of infiltration. The average infiltration rate was found to be intermediate in nature . The infiltration rate or water intake rate is initially high, but decrease with time. Infiltration rates also decreased, approaching a steady infiltration rate with time. The soil was medium acidic to sub-tropical climate. The high bulk density of the dumps was evidently influenced by the use of machinery. This has serious implication for subsequent change of soil properties because gaseous diffusion is made more difficult. Such high bulk density would pore restrictions on the growth of deep-rooted plants and may be one of the reasons of cessation of plant growth at the shrub stage. The porosity was found to be less than that found in unmined soil due to that found in unmined soil due to compaction during excavation and, as a result, plants cannot grow smoothly. For good plant growth, bulk density should be below 1.4-g cm-3 for clays and 1.6g cm"3 for sand. The most useful water parameters of the soil relating to plant growth, are moisture content, field capacity, water-holding capacity and the wilting coefficient that were found to be lower in the soil dump samples than those of unmined soil and decreased slightly with age due to the decrease in organic carbon. It is also reported a decrease in soil water holding capacity as a result of storage. The greater value of the wilting coefficient indicates the deficiencies of the plant growth materials. The pH of soil dumps was acidic due to leaching of basic cations. Under such acidic conditions, H-ion toxicity, high availability of Al and Mn and unavailability of Mo are the principal deterrents of plant growth. A pH range of 6.5 to 7.5 is optimum for plant nutrient availability. Electrical conductivity decreased with the increasing age of the soil dump but was higher than the surrounding unmined soils. A mixing of lower surface horizons may cause this. The action exchange capacity of soil dumps was lower than unmined soils and decreased with increasing age of the soil dumps. Again, the mixing of the lower soil horizons may cause this. Similar trends were also observed for exchangeable Ca, Mg, Na, and K. The organic carbon gradually decreased with the increasing age of soil dumps, probably due to low humification by the lake of soil micro flora. The organic carbon content levels in unmined soil decreased markedly with storage to about 47% levels in the 1-year-old, about 23% in the 1-6 year-old dumps and about 6% in 6-10 year old dumps. It appears that after 6 years the organic carbon content reached a steady state condition. The available phosphorous was much lower than the available nitrogen and potassium because most of the phosphorous present in the soil is not readily available to plants. The deficiency in nutrients was probably caused by the reduction in soil microbes induced by stockpiling and excessive leaching. Available macronutrients (NPK) decreased considerably in comparison to unmined soil and also decreased with the increasing age of the soil dumps. This may be produced by the reduction in soil microbes caused by stockpiling and excessive leaching. Available nitrogen was found to decrease rapidly in 1-year-old dumps (31%), and gradually decreased in 1-6 years-old dumps (27%), reaching a stagnant condition (5%) in 6-10 years. A similarly decreasing trend was also observed for the available phosphorous content from 23% (1 year) to 6 % (6-10 years), and potassium, from 28% (1 year) to 18% (1-6 years) to 11% (6-10 years). Mn and Fe were found to increase as soil dumps aged. In dumps of a 1-6 year-old age range the available Fe was not found to be toxic to plants, but in 9-10 year-old dumps Fe concentration was toxic. Changes in microbial numbers due to the increased age of soil dumps showed a continuous decrease every year and at the end of the 6th year the number decreased to a minimum level This period up to the 6th year may be considered as the shelf life period of the topsoil in that particular area. As discussed earlier shelf life of topsoil means the time over which stored things remain usable by technical reclamation only. The change in soil quality will be drastic in the first year and it would continually deteriorate every year due to the loss of nutrients by leaching. The organic carbon and NPK values will come to a stagnant condition and will microbiologically be decreased to a minimum level. This period may be called the shelf life in that particular area. The shelf life of topsoil indicates the period over which the mine soil will maintain its sustainability for suitable plant growth without major biological reclamation. The user agencies are the different mining companies and the applications of shelf life concept are immense. The outcome of invention is that systematic handling and storage practices can protect physical and chemical properties of the topsoil. It should be stockpiled only when it is not feasible to promptly redistribute such materials on regarded areas. By critically analyzing the deterioration of soil characteristics in stockpiled soil, the shelf life period can be ascertained. It is essential to know shelf life period to choose whether biological reclamation is essential to preserve topsoil or it can be preserved by technical reclamation only. The invention identifies the reason behind the biological sterility of stockpiled soil. The adverse climatic conditions in India are also responsible for such situation in some ways. In India average rainfall is high but it is not uniformly distributed throughout the year. It falls heavily during two months of the year and the nutrients released by microbiological activity are lost entirely by leaching and erosion. It should be stockpiled only when it is not feasible to promptly redistribute on regarded areas. However, if storage is unavoidable, stockpiled topsoil should be reclaimed biologically when the redistribution of such materials over the regarded areas requires beyond the shelf life period. A prior knowledge of topsoil shelf life would enable mine planners to draw up an appropriate strategy for topsoil excavation vis-a-vis mine scheduling. An appropriate concurrent and post mining reclamation strategy can also be determined. This wills not only save time but also save money. Another important out come of this study is the development of an innovative approach for the shortening of the study period. Hopefully, the methodology adopted for the present study may have formed a guideline for the determination of shelf life period of topsoil, for systematic handling and storage practices of topsoil for mining areas and renewal of damaged for sustainable beneficial use. It is claimed that the methodology will be useful on industrial scale for various sites. I claim 1. The method of determining the period of sustainability of stockpiled mined soil for plant growth in mining areas comprising the steps of - measurement of soil properties as herein described, required for plant growth on different aged stockpiled mined soil dumps and unmined land of similar geographical conditions. - analysis of the deterioration of soil properties stockpiled mined soil with respect to time. - determining the said period of sustainability as the time period till which the soil have the soil properties required for plant growth as in case of unmined soil of similar conditions. 2. The method as claimed in claim 1, wherein soil properties are texture, pore space, field moisture, field capacity, water holding capacity (WHC), wilting capacity, pH, electrical conductivity (EC), cation exchange capacity (CEC), Ca, Mg, Na, K, sodium absorption ratio (SAR), organic carbon (OC), phosphorous, microbial population. 3. The method as claimed in claim 1, wherein it is applicable specifically in opencast mining areas having similar geographical conditions and soil properties as herein described The method of determining the period of sustainability of stockpiled mined soil for plant growth in mining areas comprising the steps of measurement of soil properties such as texture, pore space, field moisture, field capacity, water holding capacity (WHC), wilting capacity, pH, electrical conductivity (EC), cation exchange capacity (CEC), Ca, Mg, Na, K, sodium absorption ratio (SAR), organic carbon (OC), phosphorous, microbial population required for plant growth on different aged stockpiled mined soil dumps and unmined land of similar geographical conditions, analysis of the deterioration of soil properties stockpiled mined soil with respect to time and finally determining the said period of sustainability as the time period till which the soil have the soil properties required plant growth as in case of mined soil of similar conditions

Full Text

1.0 Field of invention
This invention relates to a noble method of determining the sustainability period of
stockpiled soil for suitable plant growth without biological reclamation.
2.0 Back ground of the invention
Opencast mining is progressively increasing in India"s coal production. In the process of
opencast mining, the area is completely stripped of vegetation to remove the overburden covering
the coal seam. There are several changes occur in the physical, chemical and microbiological
properties of soils as a result of storage. Some caused by the actual construction of the store rather
than during the course of storage. By for the greatest impact of mining on the nation"s soil
resources is due to opencast mining, which is having a very much potential for the deterioration of
soil quality than underground operations. The following qualitative losses suffered by dug topsoil
over time:
i) Complete loss of profile due to mixing of soil horizons,
ii) Dominance of sand particles indicating low stability of aggregates,
iii) Decrease of the silt and clay fraction due to increased erosion,
iv) Increase of bulk density and pore spaces arising out of the use of earth moving
heavy machineries. As a result gaseous diffusion becomes more difficult and
restricts growth of deep-rooted plants.
v) Decrease of moisture retention properties due to changes of topography,
vi) Increase in wilting capacity indicates the deficiency of plant growth materials,
vii) Increased acidity due to leaching of basic cations and increase of soluble salts due
to the mixing of lower soil horizons,
viii) Decrease in cation exchange capacity (CEC) owing to the presence of low content
of organic matter and decrease of clay percent,
ix) Increase in organic carbon and total nitrogen probably due to low humification due
to the lack if soil micro flora.
x) Increase in C/N ratio due to lack of microbial decomposition,
xi) Reduction in fertility status (NPK) due to maximum leaching and mixing of soil
horizons.
xii) Increase of the concentration of available (Diethylenetriamine pentacetic acid
i.e.DTPA extractable) iron and manganese due to increase of acidity.
xiii) Reduction in soil microbes due to the presence of low concentration of organic
carbon, moisture and other edaphic factors.
xiv) Reduction in native seed species due to degradation of soil characteristics.
Mineral extraction process must ensure the return of the productivity of the affected land. With
the rising environmentalism concurrent post-mining reclamation of the degraded land has become
integrated feature of the whole mining spectrum. Conservation and reclamation efforts to ensure
continued beneficial use of land resources are essential. Opencast mining severely disturbs land in
and around mining areas. It is reported that every million tonne of coal extracted by surface
mining methods damage a surface area of about 4 ha in India. The coal industry alone accounts for
rendering biologically unproductive area of about 500 ha a year during 1994-95, which rose to
1400 ha a year by 2000 AD.
The topsoil must be mined separately at the beginning of the mining operation. This is
particularly necessary in coal mining areas due to the scarcity of soil in the coalfields. Five years
or more may pass between the removal of topsoil and its replacement over the reclaimed area.
During this time the soils are found to become biologically sterile, and its nutrient value are found
to be lost completely The US Department of Interior regulations require that topsoil should be
removed in a separate layer from the areas to be disturbed. The main environmental factors
inhabiting the plant growth in soil dumps are instability, unknown steep slopes, high levels of
toxic elements, wind erosion and low nutrient status and absence of soil microorganism and soil
fauna. Stockpiling of soil materials has been found to degrade the soil quality by decreasing the
organic matter content, disrupting nutrient cycles and increasing the bulk density. Areas damaged
by mining depend on seam thickness, stripping ratio and quarry depth. Direct damage to land takes
place due to excavation and creation of overburden, mineral dumps, civil structures, roads and
colonies. Indirect damage takes place due to water pollution, hydrological disturbance, silting and
run off. Opencast mining also leads to rapid erosion of land because of slope stability problems
and sometimes it may cause landslides. Land degradation may result in soil erosion leading to the
destruction of watersheds, siltation and loss of valuable fertile soil. To combat these situation a
fact finding survey is essential
3.0 Drawback associated with the known art
Topsoil is an essential component in abandoned mines for growth of vegetation and has to
be preserved for post-mining land reclamation. It is seriously damaged if it is not mined out
separately in the beginning with view to replacement of for reclamation of the area. It is necessary
to save topsoil for latter use in a manner to protect the primary root medium from the
contamination and erosion, hence its productivity. Systematic handling and storage practice can
protect the properties of topsoil while in storage and also when it has been redistributed on to the
regarded areas. It should be noted that the period between the initial removal of the topsoil and
final laying of the same over the reclamated area might be a long time lapse. So the properties of
stockpiled soil deteriorate and become biologically unproductive. The issue is the preservation of
topsoil (stockpiling) in such a manner as to protect its productivity for later use in restoration of
mined land. This problem is very much acute in India and a vast mined out areas are continually
being biologically sterile every year.
Reclamation of degraded land has become a great challenge to Indian coal mining industry.
Efforts to grow vegetation on overburden dumps and degraded mined lands as a part of biological
reclamation are not being successful. The reasons are not completely understood and no work in
this line has yet been reported As this soil is to be utilized for the reclamation of degraded mined
land it is essential to search out the reasons of mined out areas of being biologically unproductive
4.0 Object of invention
The method of determining the period of sustainability of stockpiled mined soil for plant
growth in mining areas specifically in open cast mining areas.
5.0 A summary of invention
Thus according to the present invention there is provided a method of determining the period
of sustainability of stockpiled soil for plant growth in mining areas comprising the steps of
measurement of soil properties required for plant growth on different aged stockpiled mine soil
dumps and unmined land of similar geographical conditions.
analysis of the deterioration of soil properties stockpiled mine soil with respect to time
determining the said period of sustainability as the time period till which the soil have the soil
properties required plant growth as in case of mined soil of similar conditions.
As this soil is to be utilized for the reclamation of degraded mined land it is essential to
determine the the period of sustainability of stockpiled. No systematic study has been reported to
determine shelf life period. It has been observed that prolonged stockpiling implies continual loss
of fertility, which ultimately leads to biological sterility.
Almost in every mineral-bearing zone mining and land degradation have been inseparably
connected. Irrespective of the scheme of exploitation, mining may be expected to affect the
environment and ecology of the region. By far the greatest impact of mining on India"s soil
resources with opencast mining having a greater potential for the deterioration of soil quality than
underground operations. In the process of opencast mining the area is completely stripped of
vegetation to remove the overburden covering the coal seam. There are several changes in the
physical, chemical and microbiological properties of soils as a result of storage, some caused by
the actual construction of the storage rather than during the course of storage.
Topsoil is an essential component of land reclamation in mining areas. The topsoil is very
seriously damaged if it is not mined out separately in the beginning with a view for replacement
for due reclamation of the area. This is particularly necessary to save topsoil for a later use in a
manner to protect the primary root medium from contamination and erosion and hence its
productivity. It has been indicated, however, that systematic handling and storage practices can
protect physical and chemical characteristics of topsoil while in storage and also after it has been
redistributed onto the regarded area. Monitoring and implementation of these steps in accordance
with site-specific modern technology will minimize the deterioration and provide a medium for
plant growth.
Topsoil is very useful in abandoned mines for the growth of vegetation. It is extremely
required for post mining land reclamation. It is to be excavated separately and stockpiled when it
becomes impractical to redistribute immediately. Efforts to grow vegetation on overburden dumps
and degraded mined lands as a part of biological reclamation are not being successful in India. The
reasons were not completely understood.
. It is claimed that if the shelf life period of soil in a particular area is determined, mining
authority can decide whether it becomes essential to go for cost intensive biological reclamation or
they can preserve the mined soil by technical reclamation only. This ensures the saving time as
well as money. A prior knowledge of topsoil shelf life periods would enable the mine planner to
draw up an appropriate strategy for topsoil excavation vis-a-vis mine scheduling. An appropriate
concurrent and post mining reclamation strategy can also be chalked out.
By determining the deterioration of physical, chemical and microbiological properties in
different aged soil dumps the shelf life period can be ascertained. Shelf life period indicates
whether biological reclamation is required for the stockpiled topsoil. Biological reclamation must
be adopted to preserve the topsoil if the storage period exceeds the shelf life period. If the shelf
life period of topsoil in a particular area is determined, the mining authority can decide whether it
is essential to choose biological reclamation for the preservation of topsoil or whether they can
preserve the soil by technical reclamation only. A prior knowledge of topsoil shelf life period
would enable mine planners to draw up an appropriate strategy for topsoil excavation vis-a-vis
mine scheduling. An appropriate concurrent and post mining reclamation strategy can also be
determined. This will not only save time but also save money.
Another important aspect of this invention is the shortening of time frame for the
determination of shelf life period. Generally such a study would require 10 years time to determine
the shelf period in a particular area. But an innovative approach has been developed, which
requires only 5-6 months time for the study for the determination of the said shelf life. The
techniques adopted for achieving the target are given below:
• The shelf life period in a particular area depends on climatic conditions, soil
characteristics and site-specific factors. It will vary from area to area. To determine the
shelf life period in a particular area one opencast coal mine (working) is to be
investigated.
• Unmined areas surrounding the working mine are to be investigated for the generation
of base line data of unmined soil and they are to be compared with those of mined soil
to determine the deterioration of soil quality due to mining.
• From the different aged soil dumps (1 to 10 years) and from the unmined land of
similar soil type soil samples are to be collected.
• Approach for the selection of soil sampling locations in virgin areas as well as from the
dumps, method of sampling, sample preparation, parameters to be considered
determination of soil quality, method of determination are given in the Data collection
methods section (Section 6.2).
• Representative soil samples are to be collected from different spots taken from a
uniform depth and of the same approximate volume, which are distributed at random
covering each sampling unit and twelve number of composite samples are to be
prepared
• Field tests and laboratory tests are to be conducted to generate the base line data for the
unmined land and for different aged soil dumps with respect to physical and water
retention properties, physico-chemical and ion-exchange properties, available macro
and micro nutrients and microbial population and the base line data of the unmined
land and different aged soil dumps are to be determined.
• Profile characteristics of the soil, soil physical properties, infiltration rate, water
retention properties, available macronutrients, micronutrients and microbial status of
soil are to be studied. The properties of the unmined soil are to be compared with those
of the different aged soil dumps and the deterioration of the soil properties with respect
to time is to be determined.
• The graphical representation of the deterioration of soil organic carbon, nitrogen,
phosphorous, potassium are to be plotted and the data results are to be examined to
determine the quantitative losses of soil properties with respect to time till sterility
• From the deterioration of soil physical, chemical and microbiological properties in
different aged dumps till sterility shelf life period is to be determined..
6.0 Detailed description of the invention
6.1 Description of the study area
One large opencast coal project was investigated for the determination of shelf life period.
The opencast project was the largest project of Eastern Coalfields Limited (ECL) located in the
Godda District of Jharkhand. It is situated between latitudes 24 °58"39" and 25°1"37" N and
longitudes 87°20"32" and 87 °23"58" E. The mining started in the year 1980. Target production of
coal is lOMt/y. The total volume of overburden has been worked out as 985.15 Mm3. The life of
the project is 71 years. The mineable reserve is 430.43 Mt.. The surface of excavation is about 15
sq. km. The total land requirement for the project is 2177 ha out of which 1873.81 ha is
agricultural land, 113.05 ha "danga" (cultivable waste) land and 110.56 ha forest land .Land to be
affected by direct mining will about 67% (quarry only) . The region was mostly agricultural land
(1874 ha) with a small area of wasteland (113 ha), reserved forest and sharb forest (110 ha) he
agricultural activities depend on ponds and rains. The major crops cultivated in the region were
paddy (Oryza sativa), sugar cane {Sacchurm officimarum) gram (Cicer arietimum). The most
important aspect of the invention 17 different parameters of a specific soil samples wherein
mining is done are measures. Those parameters are texture, pore space, field moisture, field
capacity, water holding capacity (WHC), wilting capacity, pH, electrical conductivity(EC), cation
exchange capacity (CEC), Ca,Mg,Na, K, sodium absorption ratio (SAR), organic carbon (OC),
phosphorous, microbial population.
6.2 Data collection methods
Determination of shelf life period includes various field tests and laboratory tests. Soil
samples were collected from the unmined land in and around the project areas. Ten numbers of
sub samples were collected from spots, which were distributed at random covering each sampling
unit. Each sub sample was taken to a uniform depth and of the same approximate volume. Twelve
numbers of composite soil samples were prepared. The depth of the topsoil varied from 15 to
22cm in the area. They were striped and stockpiled separately. Soil samples were also collected
from six different age classes (1,3,4,6,9 and 10 years old) of mine soil dumps around the working
coal mine of the opencast project, which were not vegetated.. Eight samples were collected from
each dump. The sampling location sites were randomized after site facing. The mine soil dumps
were having moderate to steep slope ranging in height 7 to 8 m. After the collection, soil samples
were air dried at room temperature and lightly crushed with mortar pastels and passed through
2mm sieve for analysis. Infiltration rates were measured by cylinder infiltrometer method. Field
capacity and bulk density were measured according to standard method. The water holding
capacity (WHC) and moisture content of the soils were measured by gravimetric methods. Soil
pH, electrical conductivity (EC), organic carbon, available nitrogen, phosphorous and potassium
were determined. The wilting coefficient was measured by plant method; cation exchange capacity
(CEC) and exchangeable cations were also determined by neutral normal ammonium acetate
method. The available micronutrient cations, i.e. iron (Fe), manganese (Mn), copper (Cu) and zinc
(Zn), were extracted with diethylene- triamine penta acetic acid /calcium chloride (DTPA-Cl2)
solution and analyzed by atomic absorption spectrophtometry.
6.3 Data results
The soil profile of unmined soil was found to be grayish in color, sub angular blocky structure, sticky
and plastic with gradual smooth boundary. In different aged soil dumps these were found to be light grayish
brown in color, single green structure, nonsticky and non-plastic and having many vertical tubular pores.
Infiltration rates (IRs.) for unmined areas were found to be 3.12 to 0.7cm h4 After 240 min, the average IRS
was 0.6cm h"1. The physical and water retention properties of unmined soil and different aged soil dumps are
given in Table I. Average values for the particle size distribution were 61.2% (sand) 27.7%(Silt) as 11.1% (Clay),
respectively. The bulk density of unmined soil was found to be 1.39 Mg/t. The bulk densities of soil dumps
gradually increased from 1.66 Mgmt for one-year-old dumps to 1.72 Mgm3 for ten-year-old dumps. The mean
value of pore space of unmined soil was found to be 47.2% for the soil dump this varied from 37.4% for a
one year old dump to 35.1% for a ten year old dump. The field moisture, maximum water holding capacity %
wilting capacity found to decrease along with the increase of age of the dumps.
Values in parentheses represent range
In unmined soil the pH value was found to be 6.38 but it was found to be decreased
gradually and at 10th year it was more acidic ( was 0.24 ds m-1 and varied for 0.36 dsm-1 (1st year) to 0.26 dsm-1 (10th year). The cation exchange
capacity of the unmined soil was found to have a mean value of 11.8 cm ol (P+) Kg -1. In the soil
dumps this value decreased gradually from 9.61 to 7.41 cmol (P+) Kg-1 with the increase of age.
Exchangeable Ca, Mg, Na, and K levels were also found to be lower than those in unmined soils.
The sodium adsorption ratio (SAR) in unmined soil was 0.14 and it was varied between 0.12 and
0.15 in soil dumps. The percentage base saturation in unmined soil was found to be 76.0% and
gradually decreased as the age of the soil dumps increased from 74.3 to 56.1%.
6.4 A brief description of the accompanying drawings
Figure 1: Variation of organic carbon in different aged soil dumps and unmined soil
Figure 2: variation of available nitrogen in different aged soil dumps and unmined soil
Figure 3: Variation of available phosphorous in different aged soil dumps and unmined soil
Figure 4: Variation of available potassium in different aged dumps and unmined soil
Figure 5: Variation of microbial population in different aged soil dumps.
The variation in the organic carbon (c) content in soil dumps and unmined soils is shown
in Figure. 1. The organic carbon content in unmined soil was 0.72% and the soil dumps were
found to be very poor and varied from 0.38 to 0.26%. The organic carbon content levels in
unmined soil decreased markedly with storage to about 47% levels in the 1-year-old dumps, about
23% in the 1-6 year-old dumps and about 6% in 6-10 year old dumps.
From Table 3 it will be seen that the mean value of available NPK in unmined soils were
221.0 kg ha-1, 8.4 Kg ha-1 and 223.6 hg ha -1 respectively .The variation in available nitrogen (N),
phosphorous (P) and potassium (K) in different aged soil dumps and unmined soils are shown in
Figures.2, .3 and .4, respectively. In soil dumps NPK values were found to decrease with
increasing age of the soil dumps over the ranges 151.7 to 112.5 Kg ha-1, 6.5 to 5.5 Kg ha-1 and
162.0 to 121.2 kg ha,-1 respectively. In unmined soils the available Fe was found to be 28.9 mgKg-
1, Mn 18.6 mg Kg-1, Cu 0.7 mg Kg-1 and Zn 0.53 mg Kg -1. The available Fe, Mn, Cu and Zn in
soil dumps showed no consistent trends with the increasing age of soil dumps. The microbial
population in soil dumps decreased sharply in comparison to unmined soil. In the one year aged
dump, the population of bacteria, actinomycetes and fungi were found to be 5 to 8 times lower.
There was a gradual decrease in population of bacteria, actimycetes and fungi from 1 to 10 year-
aged dumps (Figure. 5) and at the 10th year these were 44%, 60% and 76%, respectively. The
decrease was statistically significant. The clay content and the field moisture content showed
strong and significant positive correlation with field capacity, water holding capacity and wilting
coefficient at 1-% level (Table 4). Very high positive correlation coefficient was also observed
among organic, available nitrogen and available phosphorous, while available potassium did not
show strong correlation with other parameters (Table 5). Changes in microbial numbers due to the
increased age of soil dumps showed a continuous decrease every year and at the end of the 6th year
the number decreased to a minimum level. (Table 6).
F.M. = Field moisture; O. C. = Organic Carbon; B = Bacteria;
A = Actinomycetes; F= Fungi
6.5 Determination of shelf life period
Particle size analysis revealed that sand particles increased, silt and clay particles
decreased, with respect to unmined soil. This trend may be because of increased erosion.
Dominance of sand particles indicated low stability of aggregates and consequently a high rate of
infiltration. The average infiltration rate was found to be intermediate in nature . The infiltration
rate or water intake rate is initially high, but decrease with time. Infiltration rates also decreased,
approaching a steady infiltration rate with time.
The soil was medium acidic to sub-tropical climate. The high bulk density of the dumps
was evidently influenced by the use of machinery. This has serious implication for subsequent
change of soil properties because gaseous diffusion is made more difficult. Such high bulk density
would pore restrictions on the growth of deep-rooted plants and may be one of the reasons of
cessation of plant growth at the shrub stage. The porosity was found to be less than that found in
unmined soil due to that found in unmined soil due to compaction during excavation and, as a
result, plants cannot grow smoothly. For good plant growth, bulk density should be below 1.4-g
cm-3 for clays and 1.6g cm"3 for sand. The most useful water parameters of the soil relating to plant
growth, are moisture content, field capacity, water-holding capacity and the wilting coefficient
that were found to be lower in the soil dump samples than those of unmined soil and decreased
slightly with age due to the decrease in organic carbon. It is also reported a decrease in soil water
holding capacity as a result of storage. The greater value of the wilting coefficient indicates the
deficiencies of the plant growth materials. The pH of soil dumps was acidic due to leaching of
basic cations. Under such acidic conditions, H-ion toxicity, high availability of Al and Mn and
unavailability of Mo are the principal deterrents of plant growth. A pH range of 6.5 to 7.5 is
optimum for plant nutrient availability. Electrical conductivity decreased with the increasing age
of the soil dump but was higher than the surrounding unmined soils. A mixing of lower surface
horizons may cause this. The action exchange capacity of soil dumps was lower than unmined
soils and decreased with increasing age of the soil dumps. Again, the mixing of the lower soil
horizons may cause this. Similar trends were also observed for exchangeable Ca, Mg, Na, and K.
The organic carbon gradually decreased with the increasing age of soil dumps, probably
due to low humification by the lake of soil micro flora. The organic carbon content levels in
unmined soil decreased markedly with storage to about 47% levels in the 1-year-old, about 23% in
the 1-6 year-old dumps and about 6% in 6-10 year old dumps. It appears that after 6 years the
organic carbon content reached a steady state condition. The available phosphorous was much
lower than the available nitrogen and potassium because most of the phosphorous present in the
soil is not readily available to plants. The deficiency in nutrients was probably caused by the
reduction in soil microbes induced by stockpiling and excessive leaching. Available
macronutrients (NPK) decreased considerably in comparison to unmined soil and also decreased
with the increasing age of the soil dumps. This may be produced by the reduction in soil microbes
caused by stockpiling and excessive leaching. Available nitrogen was found to decrease rapidly in
1-year-old dumps (31%), and gradually decreased in 1-6 years-old dumps (27%), reaching a
stagnant condition (5%) in 6-10 years. A similarly decreasing trend was also observed for the
available phosphorous content from 23% (1 year) to 6 % (6-10 years), and potassium, from 28%
(1 year) to 18% (1-6 years) to 11% (6-10 years). Mn and Fe were found to increase as soil dumps
aged. In dumps of a 1-6 year-old age range the available Fe was not found to be toxic to plants, but
in 9-10 year-old dumps Fe concentration was toxic.
Changes in microbial numbers due to the increased age of soil dumps showed a continuous
decrease every year and at the end of the 6th year the number decreased to a minimum level This
period up to the 6th year may be considered as the shelf life period of the topsoil in that particular
area.
As discussed earlier shelf life of topsoil means the time over which stored things remain usable
by technical reclamation only. The change in soil quality will be drastic in the first year and it
would continually deteriorate every year due to the loss of nutrients by leaching. The organic
carbon and NPK values will come to a stagnant condition and will microbiologically be decreased
to a minimum level. This period may be called the shelf life in that particular area. The shelf life
of topsoil indicates the period over which the mine soil will maintain its sustainability for suitable
plant growth without major biological reclamation.
The user agencies are the different mining companies and the applications of shelf life
concept are immense. The outcome of invention is that systematic handling and storage practices
can protect physical and chemical properties of the topsoil. It should be stockpiled only when it is
not feasible to promptly redistribute such materials on regarded areas. By critically analyzing the
deterioration of soil characteristics in stockpiled soil, the shelf life period can be ascertained. It is
essential to know shelf life period to choose whether biological reclamation is essential to preserve
topsoil or it can be preserved by technical reclamation only.
The invention identifies the reason behind the biological sterility of stockpiled soil. The
adverse climatic conditions in India are also responsible for such situation in some ways. In India
average rainfall is high but it is not uniformly distributed throughout the year. It falls heavily
during two months of the year and the nutrients released by microbiological activity are lost
entirely by leaching and erosion.
It should be stockpiled only when it is not feasible to promptly redistribute on regarded areas.
However, if storage is unavoidable, stockpiled topsoil should be reclaimed biologically when the
redistribution of such materials over the regarded areas requires beyond the shelf life period. A
prior knowledge of topsoil shelf life would enable mine planners to draw up an appropriate
strategy for topsoil excavation vis-a-vis mine scheduling. An appropriate concurrent and post
mining reclamation strategy can also be determined. This wills not only save time but also save
money. Another important out come of this study is the development of an innovative approach
for the shortening of the study period. Hopefully, the methodology adopted for the present study
may have formed a guideline for the determination of shelf life period of topsoil, for systematic
handling and storage practices of topsoil for mining areas and renewal of damaged for sustainable
beneficial use. It is claimed that the methodology will be useful on industrial scale for various
sites.
I claim
1. The method of determining the period of sustainability of stockpiled mined soil for plant
growth in mining areas comprising the steps of
- measurement of soil properties as herein described, required for plant growth on
different aged stockpiled mined soil dumps and unmined land of similar geographical
conditions.
- analysis of the deterioration of soil properties stockpiled mined soil with respect to time.
- determining the said period of sustainability as the time period till which the soil have the
soil properties required for plant growth as in case of unmined soil of similar conditions.
2. The method as claimed in claim 1, wherein soil properties are texture, pore space, field
moisture, field capacity, water holding capacity (WHC), wilting capacity, pH, electrical
conductivity (EC), cation exchange capacity (CEC), Ca, Mg, Na, K, sodium absorption
ratio (SAR), organic carbon (OC), phosphorous, microbial population.
3. The method as claimed in claim 1, wherein it is applicable specifically in opencast mining
areas having similar geographical conditions and soil properties as herein described
The method of determining the period of sustainability of stockpiled mined soil for
plant growth in mining areas comprising the steps of measurement of soil properties such as
texture, pore space, field moisture, field capacity, water holding capacity (WHC), wilting
capacity, pH, electrical conductivity (EC), cation exchange capacity (CEC), Ca, Mg, Na, K,
sodium absorption ratio (SAR), organic carbon (OC), phosphorous, microbial population
required for plant growth on different aged stockpiled mined soil dumps and unmined land of
similar geographical conditions, analysis of the deterioration of soil properties stockpiled
mined soil with respect to time and finally determining the said period of sustainability as the
time period till which the soil have the soil properties required plant growth as in case of
mined soil of similar conditions

Documents:

445-cal-2002-granted-abstract.pdf

445-cal-2002-granted-claims.pdf

445-cal-2002-granted-description (complete).pdf

445-cal-2002-granted-drawings.pdf

445-cal-2002-granted-form 1.pdf

445-cal-2002-granted-form 18.pdf

445-cal-2002-granted-form 2.pdf

445-cal-2002-granted-form 3.pdf

445-cal-2002-granted-letter patent.pdf

445-cal-2002-granted-reply to examination report.pdf

445-cal-2002-granted-specification.pdf

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Patent Number

212136

Indian Patent Application Number

445/CAL/2002

PG Journal Number

47/2007

Publication Date

23-Nov-2007

Grant Date

20-Nov-2007

Date of Filing

26-Jul-2002

Name of Patentee

DR. MRINAL KANTI GHOSH

Applicant Address

CENTRE OF MINING ENVIRONMENT, INDIAN SCHOOL OF MINES, DHANBAD-826004.

Inventors:

#	Inventor's Name	Inventor's Address
1	DR. MRINAL KANTI GHOSH	CENTRE OF MINING ENVIRONMENT, INDIAN SCHOOL OF MINES, DHANBAD-826004.

PCT International Classification Number

A 01 G 31/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA