阅读说明：本技术 一种基于露天煤矿排岩场土地复垦废岩土壤化的方法 (Method for land reclamation of waste rock soil based on open pit coal mine rock dumping field ) 是由 徐友宁 杨敏 陈华清 于 2020-03-05 设计创作，主要内容包括：本发明属于生态环境防治技术领域,公开了一种基于露天煤矿排岩场土地复垦废岩土壤化的方法,在评估计算露天煤矿可采煤层之上不同沉积岩的岩性差异及空间分布的基础上,进行错台开挖、分类剥离可采煤层之上的不同类型的岩石(废岩),将废岩分类转运、堆积在排岩场(排土场)的不同位置,分层压实,表层堆积露天煤矿自身存在的风化煤、碳质页岩、页岩、泥岩等,代替土地复垦用的土壤,与矿山职工厨余生活垃圾混合发酵营养化、有机化,完成废岩土壤化的技术方法。本发明实现了绿色开采的废岩土壤化、废岩资源化、职工生活垃圾无害化的处理方法,创新形成了露天煤矿土地复垦无土化的土地复垦新模式,环境效应、经济效益和社会效应巨大。(The invention belongs to the technical field of ecological environment control, and discloses a method for land reclamation waste rock soil formation based on a strip rock yard of an opencast coal mine. The invention realizes the method for treating the waste rock soil for green mining, the waste rock resource and the worker domestic garbage harmlessness, innovatively forms a new land reclamation mode for the land reclamation of the open pit coal mine without soil, and has great environmental effect, economic benefit and social effect.)

1. The method for land reclamation waste rock argillization based on the opencast coal mine rockfall field is characterized in that on the basis of evaluating and calculating differences and spatial distribution of lithology of sedimentary rocks above a mined coal bed of an opencast coal mine, the method comprises the steps of excavating, classifying and stripping, classifying and transferring, classifying and stacking at different positions of the rockfall field through waste rock staggered platforms above the coal bed, layering and compacting, wherein weathered coal, carbonaceous shale, shale and mudstone are adopted on the surface layer to replace land reclamation soil; the waste is mixed with kitchen garbage of mine workers, fermented, cured and nourished to form the integration of coal resource mining, waste rock stripping, classified stacking and land reclamation projects of an open pit coal mine.

2. The method for reclamation of waste rock agrariation of a quarry land based on an opencut coal mine as recited in claim 1, wherein the utilization of the requirements before the mine staff kitchen waste, toilet waste and carbonaceous shale species of the quarry are mixed:

analyzing lithological differences and distribution of different sedimentary rock strata symbiotic above a coal seam, and delineating and calculating the spatial distribution and volume of weathered coal, carbonaceous shale, shale and mudstone;

secondly, carrying out layered stripping on the waste rocks by using a surface mining excavator, and carrying out classified transfer on the waste rocks to a rock dumping field by using an automobile or a conveyor belt;

and thirdly, stacking coarse sandstone, fine sandstone, mudstone, shale, carbonaceous shale and weathered coal in sequence from the bottom to the surface of the rock dumping field, and layering and compacting.

3. The method for reclamation of waste rock agrinization of pit coal mine quarry land as recited in claim 2, wherein the first step of analyzing differences and distribution of lithologies of different sedimentary rock formations paragenetic over a coal seam comprises:

(1) according to the subsequent positions of different lithologic rocks in a rock dumping field, the difference of replacing soil and the characteristics of resource, the rocks within the open pit coal mining boundary range are classified into three categories:

1) hard sandstones that are not prone to weathering, the hard sandstones comprising: conglomerate, coarse sandstone, fine sandstone;

2) mudstone species with clay minerals;

3) easily weathered carbonaceous shales having a high organic content, the carbonaceous shales including weathered coal and carbonaceous shales;

calculating the volume according to the occurrence, thickness and distribution range, and drawing a rock thickness contour map in an opencast coal mining boundary;

(2) calculating the type of the stripped waste rock according to the parameters of the land occupation range, the stacking height, the slope gradient and the type of the reclaimed land of the dumping yard, and optimizing the stacking space position relationship of the dumping yard;

(3) according to the calculation result, the open pit mining plan is combined, the sequence of top-down waste rock classification stripping and staggered platform excavation of the open pit is optimized, and the technology of rock separation transport and rock separation for stacking different waste rocks in the rock discharge yard space is optimized.

4. The method for reclaiming waste rock agrification in a strip mine quarry land based on claim 3, wherein the sandstone species piled at the middle lower part of the quarry comprises conglomerate, sandstone, siltstone; the rocks accumulated on the surface of the rock dumping field to replace soil are carbonaceous shales including weathered coal, carbonaceous shales, shales and mudstones.

5. The method for waste rock agrification in land reclamation based on the quarry of open pit coal mine according to claim 3, wherein the distribution of weathered coal, carbonaceous shale, mudstone within the openpit coal mining environment is plotted in thickness, and the volume of the distribution is calculated as the type of rock which is mainly stripped and land reclamation rock agrification.

6. The method for reclaiming waste rock materialization of rock field land based on opencut coal mine dumping field of claim 3, wherein the reclaimed land type comprises woodland, woodland or grassland, area of cultivated land, range, casing thickness.

7. The method for reclaiming waste rock agroinization in open pit coal mine waste rock site land of claim 2, wherein the method for reclaiming waste rock agroinization in open pit coal mine waste rock site land is used for formulating a waste rock classification stripping technology process on a mined coal bed according to the relationship of the calculated stripping waste rock and the amount of the lithology of the surface layer of the waste rock site capable of being agroinized; the lithology on the strip coal seam of the strip mine is stripped according to the classification of sandstone, shale and carbonaceous shale; wherein, the carbonaceous shale and the weathered coal must be separately stripped, classified, transported and stacked on the top layer of the rock dumping field.

8. The method for reclaiming waste rock agroforestry in opencut coal mine quarry land of claim 7, wherein the sandstone includes conglomerate, sandstone, siltstone, and can be mixed and stripped, and mixed and piled in the quarry.

9. The method for reclaiming waste rock in land based on an opencast coal mine quarry as claimed in claim 1, wherein the second step comprises the steps of stripping by layers and classified transportation to the quarry by an opencast mining excavator, wherein the classified stripping and classified transportation of the opencast coal mine comprise the steps of stripping by classification and classified transportation of the quarry, and sandstone with high hardness, difficult differentiation and easy formation of large stones after excavation are stacked at the bottom of the quarry, wherein the large stones with diameters of more than 50cm can be stacked in the toe region of the quarry alone, and the large stones can be dry-piled to form sandstone retaining walls or can be stacked at appropriate positions of the mine for landscaping; piling coarse sandstone, fine sandstone, mudstone, shale, carbonaceous shale and weathered coal in the rock dumping field from the bottom to the top in sequence; performing mechanical compaction while pushing and accumulating; stacking carbonaceous shale, weathered coal or shale on the surface layers of a rock dumping field platform and a step zone for land reclamation; reclaiming cultivated land, wherein the compaction coefficient of the carbonaceous shale waste rock paved on the surface layer is not less than 0.80, the final thickness is 50cm, the grassland thickness is 30cm, and the forest land thickness is 50 cm; if the quantity of the carbonaceous shale is insufficient, the forest land can adopt a pit method, and only the pit is paved with covering soil with the thickness of 100 cm.

10. The method for waste rock reclamation based on the quarry land of the opencut coal mine as claimed in claim 1, wherein the method for waste rock reclamation based on the quarry land of the opencut coal mine further comprises processes of waste rock reclamation, compound fertilizer eutrophication of the quarry land, and green manure organization of leguminous class.

Technical Field

The invention belongs to the technical field of ecological environment control, and particularly relates to a method for land reclamation waste rock soil formation based on a rock dumping field of an opencast coal mine.

Background

Currently, opencast coal mining achieves the purpose of mining underground coal resources by stripping surface vegetation, soil and rocks. Generally, the thickness of the cover layer above the coal seam is generally less than 100m, the cover layer is too thick, open-pit coal mining is not economical, and an underground mining mode needs to be changed. In open pit coal mining, rocks (sandstone, shale and shale) above a mined coal seam are stripped, and the stripped rocks are piled as solid wastes (waste rocks) in a place close to an open pit, namely a rock dumping field. Therefore, a deep large mining pit with dozens of steps and a huge rock discharge field can be formed in a mining area after the strip mine is mined. The former digging and damaging woodland, grassland, cultivated land and wasteland; the latter waste rock heaps occupy woodland, grassland, arable land or wasteland. Therefore, the department of natural resources requires mine enterprises to carry out land reclamation work on open-air dug and damaged land and waste residue accumulation and pressure occupation land, and the negative influence of mining resources on the ecological geological environment of a mining area is reduced.

Land reclamation refers to the condition that the land damaged by the construction project can be utilized after being renovated. The mine land reclamation work is based on fully investigating and researching the land utilization type around the mine, and the forest land, the grassland, the cultivated land, the construction land or the tourism land is recovered according to the local land utilization planning requirement of the mining area. The steps, the bottom pit and the rock dumping field of the open-pit mine all need land reclamation, but the rock dumping field is the most main land reclamation object of the open-pit mine, and the most basic requirement is to restore the original function of the land occupied by the waste rock heaped up or form a new land utilization type through development type treatment, so that a new industry is formed. In general, the most important direction of land reclamation is to restore woodland, grassland, and cultivated land.

At present, the conventional method for recovering woodland, grassland or cultivated land in a strip mine rock removal field is as follows: during mining of most mining enterprises, surface soil within the excavation boundary range of the open-pit coal mine and surface soil within the planned rockyard occupation range are mechanically stripped within a certain time before digging, damage and occupation, and the part of soil with plant survival is independently stacked in a surface soil stacking and arranging field or directly used as soil for land reclamation of a rockyard table top and steps which are already stacked. The effective thickness of the surface soil of the reclaimed forest is 50cm, the grassland is 30cm, and the cultivated land is 80 cm. Land reclamation generally requires soil improvement, i.e., curing of green manure in soil dressing or eutrophication of compound fertilizers. The reclaimed soil is mainly surface soil dug and damaged and compacted in the mine or outsourced foreign soil (residual slope, loess and the like). However, in most cases, the surface soil is not present in the area of the mine, or the soil layer is too thin to be mechanically stripped, so that the surface soil and rock in the surface mine are usually stripped together (the stripping cost is saved), and the surface soil and rock are mixed and accumulated in the rock dumping site. Subsequent land reclamation requires outsourcing of additional soil.

Soil is the most important factor of ecological environment and is the source of nutrients necessary for plant growth. Soil is a product of rock weathering, but under general conditions, the rock weathering process is extremely slow under natural conditions, and a long process of over ten thousand years is needed for the weathering of granite into soil. Relevant researches show that the time consumed for forming the soil with the thickness of 1cm is about 300-400 years, so that the soil has certain non-regenerability. But some rocks are easily earthed due to their lithological characteristics, such as carbonaceous shale, weathered coal, shale, and the like.

Soil is composed of solid matter (minerals, organic matter and microorganisms), liquid (soil moisture) and air in soil pores, and is the material basis for soil fertility. Soil organic matter mainly comes from applied organic fertilizers and residual stubbles. The minerals and humus are the main body of the soil, accounting for about 50% of the volume of the soil, and the pores between solid particles are occupied by gas and moisture.

The content of organic matters in the soil is an important mark for measuring the soil fertility, and the content of the organic matters in a plough layer of a common cultivated land only accounts for 0.5-2.5% of the dry weight of the soil. The soil organic matter comprises fresh organic matter, semi-decomposed organic matter and humus. The humus accounts for more than 85-90% of the total organic matter of the soil. The humus contains a large amount of nutrient elements such as nitrogen, phosphorus, potassium, sulfur, calcium and the like, and also contains various trace elements. The humus has the functions of enhancing the water absorption and fertilizer retention capacity of soil, improving the physical properties of the soil, improving the looseness and air permeability of the heavy soil and changing the loose state of sandy soil. The soil has the functions of water retention, ventilation and nutrition.

Coal is a sedimentary fossil energy source which is transformed by a large number of plants buried underground hundreds of millions of years ago through earth crust change, complex biochemical action and physicochemical action, and belongs to sedimentary mineral products. The geology of China has two most main coal-forming periods in history: the diadson of Shi-jiao (about 2.8-3.5 hundred million years from today) and Jurassic (about 1.4-1.95 hundred million years from today). Sedimentary rocks that co-exist with coal seams are primarily conglomerates, sandstones, siltstones, mudstones, shales, or carbonaceous shales. Sandstone is classified into coarse sandstone, fine sandstone, siltstone, and the like according to the particle size. Gravel-containing, so-called gravel-containing sandstone or conglomerate. The sandstone is rock consisting of debris substances with the granularity of 2-0.1 mm, the sand content is usually more than 50%, and the main components are quartz and feldspar. The particle size fraction of 0.1-0.01 mm in the siltstone is more than 50%, and quartz is mainly used. The mudstone is a rock consisting of clay minerals with the granularity of less than 0.0039mm, has a very fine structure, cannot be identified by naked eyes, and is a clay rock with an unobvious layer, and the clay minerals are hydromica, kaolinite, montmorillonite and the like. The mudstone is soft, has the performances of water absorption, adhesion, fire resistance and the like, and can be used for industries such as brick making, tile making, pottery making and the like. Shale has lamellar or lamellar joints, is called shale because of clear layering and easy peeling, and is easy to be weathered into fragments and tiny powder.

Carbonaceous shale: shale is a kind of shale, has a lamellar or lamellar structure, is named after containing a large amount of carbonized organic matters, and is commonly used in the top plate and the bottom plate of a coal-based stratum. When the excavator is used for excavation, the excavator is easy to crack into fragments and is easy to soften with water, and the content of organic matters reaches 3-10%. In part of coal-series strata of mines, weathered coal also exists.

Weathered coal: the chemical and physical properties of the coal layer exposed on the earth surface or buried in a shallow part are changed obviously after weathering, and the coal layer is actually not coal. The weathered coal is soft in texture, easy to twist and crush and black brown after being crushed. Because of high humic acid content, the humic acid ammonium fertilizer can be prepared by direct ammoniation. The weathered coal generally contains 25-40% of water and 40-80% of organic matters, wherein a part of the organic matters are humic acid. Therefore, the weathered coal can be used for producing sodium humate, potassium humate, humic acid urea, fulvic acid, humic acid organic-inorganic compound fertilizer and water-soluble fertilizer, and can also be used for producing petroleum drilling fluid treating agent and ceramic additive. Of course, the method is also a good substitute for land reclamation.

The coal-series stratum above the mined coal bed (which may be one layer of coal or multiple layers of coal) of the opencast coal mine is formed by rock rocks which are generally formed by mudstone or shale/carbonaceous shale + coal bed + sandstone + siltstone + mudstone or shale, and the rock rocks are vertically stacked (shown in figures 2 and 3). Various sandstone strata are mainly composed of feldspar and quartz minerals, the rocks are hard and are mostly blocky after mining, are not easy to be weathered into fine powder, and almost have no organic matters, so that the process of soil formation is difficult and long in time, the sandstone strata cannot be used as surface soil for reclamation, and only can be stacked at the bottom of a rock dumping site or used for constructing a retaining wall.

The characteristics of the mudstone, the shale, the carbonaceous shale and the weathered coal are easy to differentiate and break, high in organic matter content and rich in clay minerals, and the characteristics of the clay minerals and the soil with similar content to that of the soil, so the lithology is a valuable resource which is naturally existed in strip mines and can be used for reclaiming the land in a rock dumping field to replace the soil, and the weathered coal, the carbonaceous shale, the shale and the mudstone are ranked according to the conditions of superiority and inferiority for replacing the soil.

The land surface of many mountain mines in China is lack of soil or less soil, the gobi area is lack of soil, and the surface soil of the grassland area is limited, so that the lack of soil and the lack of soil become key factors for restricting land reclamation of the rock dumping field of the open-pit coal mine. According to literature, at present, 80% of surface soil stripped from mines in hundreds of open-pit mines in China is insufficient for land reclamation of rock dumping fields, so that the problem of soil utilization must be solved through outsourcing of soil sources. Outsourcing of the soil source requires 2/3 strong costs of approximately the total cost of land reclamation. Meanwhile, the soil-supply method is an unscientific method for dismantling the east wall and supplementing the west wall. Today, the soil reclamation method is greatly limited when ecological environment protection is comprehensively implemented. Therefore, the soil becomes a key problem for mine land reclamation.

Through the analysis, the prior land reclamation technical method for open pit coal mines in China is as follows:

(1) at present, most mining enterprises peel the surface soil and the rock on the mined coal bed of the opencast coal mine independently, and the surface soil is used for land reclamation. However, since the surface soil of some mines is thin, the separation alone is not economical, and the separation is mixed with the rock and mixed and accumulated. At present, most of rocks above the mined coal seam of the mine belong to mixed stripping, and a technical method for implementing classified stripping, classified transportation and classified accumulation according to lithological difference of sedimentary rocks is not provided.

(2) Reclaiming and recovering forest, planting grass or recovering farmland in the rock dumping field, wherein the soil source is the surface soil stripped from the mine and the land reclamation mode of outsourcing soil source (the land reclamation method of dismantling east wall and filling west wall). Rock existing in the mine itself with the ability to be transformed into soil is not utilized for land reclamation.

(3) At present, the method for improving the covering soil of the rock dumping field is generally a method for green manure and compound fertilizer. No method for organizing the mixed soil of the kitchen garbage, the toilet excrement and the carbonaceous shale of mine workers is adopted.

The difficulty in solving the above problems and defects is:

(1) the land reclamation replaces the substances of the traditional soil, has the basic properties of a large amount of similar soil, and can solve the key problem of the insufficient reclamation soil of the open pit coal mine dumping site;

(2) the material for replacing the traditional soil has the advantages of economic feasibility, popularization value and lower cost than the cost of purchased soil.

(3) The method has the advantages that the traditional soil is replaced, the materials are relatively easy to obtain, the mine stripping waste is well prepared, the resource utilization is realized, and the mining cost is reduced.

The significance of solving the problems and the defects is as follows:

(1) soil-oriented and resource-oriented utilization of waste rocks: the waste rock discharged by stripping in the mining of strip mine is the solid waste of mine, and the waste rock of mine is fully utilized: weathered coal, carbonaceous shale, mudstone and the like replace soil, the soil of rock is weathered, the landscape of waste rocks is recycled, the using amount of outsourcing soil is reduced, and meanwhile, the land occupation environmental problem caused by stacking of waste residues is also reduced.

(2) Constructing a new mode of land reclamation soil: the invention is based on weathered coal, carbonaceous shale, shale and mudstone waste rock above the mined coal bed of the open-pit coal mine, not only can be used for reclaiming the land in the rock dumping field of the open-pit coal mine, but also can be widely used for reclaiming the land in metal open-pit mines with weathered coal, carbonaceous shale, shale and mudstone waste rock, road and railway construction engineering fields, unused land and the like, and greatly expands the source of the land reclamation soil.

(3) The comprehensive benefits are remarkable

1) Environmental benefits: the method has the advantages that the waste rocks discharged from mines are adopted, the classification stripping of different rock types and the scientific and ordered mining activities of classification stacking are realized, the function of loaning of the waste rocks is realized, the unscientific behaviors of digging east and west walls and supplementing the west walls due to the fact that the landform and landform landscape and vegetation are ecologically destroyed caused by digging in different places are reduced, and the ecological environment destruction is reduced.

2) Social benefits are as follows: the rock properties and characteristics of the mine are fully utilized, and through scientific and orderly stripping, discharging, stacking and rock soil treatment, the novel technology and the novel method for resource utilization, quantitative reduction and discharge and harmless treatment of solid wastes are realized, a novel mode of green mining of open-pit coal mines is innovated and formed, and the sustainable development of mineral resource development and ecological environment protection is promoted.

3) Economic benefits are as follows: preliminary estimation, in an open mine producing 300 million tons of coal annually, land reclamation work of waste rock soil is adopted, the cost of reclaiming outsourcing extra soil in a dump land is saved by 1000-.

Disclosure of Invention

Aiming at the bottleneck problem of limiting the lack of soil in the open pit coal mine dumping field land reclamation, the invention provides a method for reclaiming waste rock soil on the basis of the open pit coal mine dumping field land reclamation.

The method for realizing the waste rock soil reclamation based on the open pit coal mine rock dumping field is realized by mixing kitchen garbage, toilet excrement and carbonaceous shale waste rock, mixing the kitchen garbage and the toilet excrement and the carbonaceous shale and shale in a ratio of 1: 15-1: 25, and stacking and fermenting for 20-40 days in different seasons; the weathered coal has high organic matter content, does not need to be mixed with kitchen garbage for fermentation, and can directly replace soil for reclamation. Within the range of reclaiming the grassland, laying 30cm of mixed carbonaceous shale on the surface layer of the refuse dump; in a region for reclaiming cultivated land, 50cm of carbon shale is laid in advance, cured carbon shale with the thickness of 30cm is laid on the carbon shale, and a mechanical plough share is used for ploughing; in the range of reclamation forest land, firstly, on the basis of fully laying 30cm of mixed carbonaceous shale, according to the requirements of row spacing and plant spacing for planting trees, excavating 1m by 1m pits, covering the mixed carbonaceous shale in the pits, and planting trees in the pits. The integration of open-pit coal mine coal resource mining, waste rock accumulation in a dumping yard and waste rock and soil land reclamation in a dumping yard is formed.

Furthermore, before mixed nutrition and organization, the mine workers use kitchen garbage, toilet excrement, carbonaceous shale, shale (weathered coal does not need to be mixed and directly replaces soil) and other waste rocks:

firstly, analyzing lithological differences and distribution of different sedimentary rock strata symbiotic above a coal seam;

secondly, carrying out staggered platform excavation, classification stripping and classification transfer to a rock dumping field through a surface mining excavator;

thirdly, sequentially stacking waste rocks from the bottom to the surface layer in a rock dumping field: coarse sandstone, fine sandstone, mudstone, shale, carbonaceous shale or weathered coal, and is compacted in a layered manner.

Further, the first step of analyzing lithology differences and distribution of different sedimentary rock formations symbiotic over the coal seam comprises:

(1) according to the action and the position difference of different lithologic rocks in reclamation of the rock dumping field land, the rocks within the boundary range of open coal mining are classified into three categories: calculating the volume of sandstone, mudstone and carbonaceous shale according to the production state, thickness and distribution range of the sandstone, mudstone and carbonaceous shale, and drawing a rock thickness diagram in an opencast coal mining boundary;

(2) calculating the types of the classified stripped waste rocks according to the parameters of the occupation range, the stacking height, the slope gradient, the type of the reclaimed land and the like of the rock dumping field, and optimizing the stacking space position and the required amount of the rock dumping field;

(3) according to the calculation result, the sequence of classification stripping of waste rocks from top to bottom and staggered platform excavation of the open pit is established, and the technical scheme of rock property separation transportation and rock property separation for stacking different waste rocks in the space of the rock discharge yard is established.

Further, the sandstone includes conglomerate, coarse sandstone, fine sandstone, siltstone; the carbonaceous shale is further divided into weathered coal, carbonaceous shale, shale and mudstone; and drawing a thickness line graph of the distribution of the weathered coal, the carbonaceous shale, the shale and the mudstone in the opencast coal mining boundary.

Further, the reclaimed land type includes parameters of forest land, forest (grass) land, range, area and grade of cultivated land.

Further, the method for reclaiming the waste rock in the rock dumping field land based on the opencut coal mine carries out classification stripping of the waste rock above the mined coal bed according to the relationship of the type and the amount of the waste rock which is calculated by evaluation and can be used for stripping the waste rock and the soil in the surface layer of the rock dumping field; stripping the lithology of the strip mine stripping coal seam according to sandstone, mud rock and carbonaceous shale or according to coarse sandstone, siltstone, mud rock, shale and carbonaceous shale; the carbonaceous shale and the weathered coal are required to be separately stripped, classified, transported and stacked on the surface layer of the rock dumping field.

Furthermore, the sandstone can be mixed and stripped from gravel sandstone, coarse sandstone, fine sandstone and siltstone.

Further, the second step of classified stripping and classified transfer to a rock dumping field through an open-pit mining excavator comprises classified stripping and classified transportation of open-pit coal mines, sandstone which is hard and difficult to differentiate and forms large stones through excavation is stacked at the bottom of the rock dumping field, and coarse sandstone, mudstone, shale, carbonaceous shale and weathered coal are sequentially stacked on the rock dumping field from bottom to top; and (5) performing mechanical compaction while pushing and accumulating. Stacking carbonaceous shale, weathered coal or shale on the surface of a rock dumping field platform and a step zone for land reclamation; in addition, part of large block-shaped sand rock bodies can be stacked on the slope toe of the rock dumping field to form a dry-built retaining wall, or the large block stones are stacked at a proper place of the mine to build a block stone landscape model. The method is characterized in that the reclamation grassland is directly paved by adopting weathered coal or mixed carbonaceous shale with the effective thickness of 30cm, compacted mechanically, the compaction coefficient is not less than 0.80, the ploughshare is 20cm, and grass seeds are scattered. In the region of reclamation farmland, 50cm of carbon shale is laid in advance, cured carbon shale or weathered coal with the thickness of 30cm is laid on the carbon shale, and a mechanical plough share is 20cm for planting crops; in the range of the reclaimed forest and grass land, firstly, 30cm of mixed carbonaceous shale is fully paved, and then the mixed carbonaceous shale is covered in 1m pits to plant trees.

Further, the method for reclaiming the waste rock soil on the basis of the rock dumping field of the opencast coal mine further comprises the steps of scattering compound fertilizer, planting leguminous green manure and curing the soil on the basis of the reclaimed waste rock soil of the rock dumping field. Reclamation of grasslands, cultivated lands, woodlands or woodlands.

By combining all the technical schemes, the invention has the advantages and positive effects that: the method aims at the bottleneck problem that a large amount of soil is needed for land reclamation and forest return, grass return or farmland restoration of the rock dumping field of the open pit coal mine at present, and is one of the key problems (the other problem is the problem of water) of land reclamation of the open pit coal mine in most of regions without soil or land. The invention provides a resource utilization technology of mine waste rocks (weathered coal, carbonaceous shale, shale and mudstone) capable of replacing land reclamation surface soil on a coal seam capable of being mined in an open pit coal mine. The method comprises the following steps of calculation, working procedures and technical methods of spatial distribution calculation of different rock types on a mined coal seam, classification stripping and transportation of different rock types, classification stacking, surface layer stacking and discharging of the rocks capable of being subjected to soil formation, organization with kitchen garbage, nutrition and the like.

The invention adopts the key technology of land reclamation of waste slag fields piled as mountains commonly existing in opencast coal mines, adopts the technology of exploiting waste rock soil in opencast coal mines, can realize self-use soil for land reclamation of rock dumping fields without dressing soil, realizes resource utilization of waste rock, changes the traditional technical method of land reclamation that soil and dressing soil are needed, organically combines waste rock stripping, piling and land reclamation, organically combines mineral resource development, waste rock resource utilization and mine life solid waste resource utilization, provides a new mode for ecological restoration and land reclamation of rock dumping fields of gobi areas, basement mountain areas, grassland open coal mine waste mining areas and metal mining areas in China, and has remarkable social benefit, environmental effect and economic benefit.

Compared with the prior art, the invention has the following advantages:

(1) the method is characterized in that the mine waste rock is subjected to argillization and waste rock landscaping, and a new green mine land reclamation mode is formed. The waste rock discharged by stripping in the mining of strip mine is the solid waste of the mine, and the waste rock of the mine is fully utilized: the weathered coal, the carbonaceous shale, the mudstone and the like replace soil, the boulder is used for retaining walls or stacking landscaping, the soil preparation of rocks and the landscaping of the boulder are realized, the land reclamation and the land occupation environment problem caused by stacking of waste residues are reduced, and a new green mine land reclamation mode is constructed.

(2) A new mode of land reclamation application is expanded: the invention relates to a retaining wall and a landscaping function based on the reclamation soil of the land in the rock dumping field of the opencast coal mine, such as weathered coal, carbonaceous shale, shale and mudstone waste rock above the coal mining layer of the opencast coal mine. The method can also be widely used for metal open mines with weathered coal, carbonaceous shale, shale and shale waste rock, highway and railway construction engineering fields and soil reclaimed by unused land, and greatly expands the source of the land reclaimed soil.

(3) The comprehensive benefits are remarkable

1) Environmental benefits: the method has the advantages that the waste rocks discharged from mines are adopted, the classification stripping of different rock types and the scientific and orderly movement of classification stacking are realized, the function of loaning of the waste rocks is realized, the unscientific behaviors of digging east and west walls and supplementing the west walls due to the fact that the landform, landform and landscape and vegetation are ecologically destroyed caused by digging in different places are reduced, and the ecological environment destruction is reduced.

2) Social benefits are as follows: the rock properties and characteristics of the mine are fully utilized, and through scientific and orderly stripping, discharging, stacking and rock soil treatment, the novel technology and the novel method for resource utilization, quantitative reduction and discharge and harmless treatment of solid wastes are realized, and a novel mode of green mining of an open pit coal mine is innovated and formed. The method promotes the reclamation work of open-pit mine lands in China, restores the ecological environment, reduces the social contradiction of shortage of the land for the mine lands, expands the sustainable development approach of coal resource development and ecological environment coordination, and achieves the aims of developing the silver mountains of the Jinshan mountains, repairing abandoned mines, reconstructing green water green mountains and forming new silver mountains of the Jinshan mountains.

3) The economic benefit is remarkable. Taking an open pit coal mine producing 300 ten thousand tons in one year in northern Shaanxi as an example, the comprehensive cost of purchasing foreign soil is 21 yuan/m³On the premise of the (1), the cost can be saved by only outsourcing the foreign soil in the reclamation of the grassland and the cultivated land in the rock dumping field by about 1200 ten thousand yuan. More than 200 open pit coal mines exist in China, and by analogy with the rock discharge field scale of 300 ten thousand tons per year, the soil purchasing cost can be saved by roughly estimating and replacing the alien soil by about 24 hundred million yuan. Therefore, the invention has very good application market and huge economic benefit.

The invention solves the key problems of limited land shortage and soil shortage of land reclamation, land recovery and land restoration of the strip mine rock dumping site, realizes the method for treating the waste rock soil, the waste rock resource and the worker domestic garbage harmlessness in green mining, innovatively forms a new land reclamation mode of the strip mine land reclamation without soil, and has great environmental effect, economic benefit and social effect. The invention is based on the properties of weathered coal bed, carbonaceous shale, mudstone and the like on the mined coal bed of the opencast coal mine: the clay mineral is high in mineral content and easy to weather, can be pulverized by mechanical action, contains organic matters, has the advantages similar to soil properties, can solve the bottleneck of troubling the insufficient land reclamation soil through the technical methods of scientific calculation, classified stripping, classified stacking and soil curing, and realizes the reclamation of waste rocks and the land reclamation of rock dumping fields.

Drawings

FIG. 1 is a flow chart of a method for reclaiming waste rock in a strip mine quarry land based on the embodiment of the invention.

FIG. 2 is a histogram of lithology and position of accretions at a drainage site above a mined coal seam provided by an embodiment of the present invention.

Fig. 3 is a schematic flow chart of a method for reclaiming waste rock stripping and stacking sequence based on opencast coal mine rock dumping site land provided by the embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Aiming at the problems in the prior art, the invention provides a method for reclaiming waste rock soil based on opencast coal mine rock dumping field land, and the invention is described in detail below with reference to the attached drawings.

As shown in figure 1, the method for reclaiming waste rock in the rock dumping field land based on the opencast coal mine provided by the invention comprises the following steps:

s101: according to the purpose of the soil quantity for reclaiming the land of the rock dumping field, the exploration data is utilized to evaluate and calculate the spatial distribution and the volume of sandstone, mudstone and carbonaceous shale within the boundary range of the open-pit coal mining, and the stripping and stacking mode, the sequence and the quantity of the rock of the open-pit coal are revised.

S102: and (3) slab staggering of the open pit coal mine is performed to strip different large rocks (sandstone, mud and carbonaceous shale), and mechanical excavation and classified transportation are performed.

S103: according to the waste rock stacking requirement of a rock dumping field, sands rock, mud rock and carbonaceous shale are sequentially stacked from the bottom to the surface layer, layered compaction is carried out, according to different types of reclaimed land, 30-80cm of carbonaceous shale (weathered coal, carbonaceous shale and shale) is covered, and mechanical leveling compaction is carried out. Meanwhile, hard large stones are accumulated in a toe zone of the rock dumping field to form a rock retaining wall stable side slope, and in addition, landscapes can be accumulated at a proper position to play a role in recycling waste of the hard stones.

S104: and (3) mixing, stacking and fermenting the carbonaceous shale on the surface layer of the waste dump and the mine domestic kitchen garbage and the like, and flattening to finish the soil reclamation by replacing the waste rock with the land.

The method for reclaiming the waste rock into the soil based on the open pit coal mine rock dumping field provided by the invention specifically comprises the following steps:

(1) an evaluation method of stratum lithology distribution based on open pit coal mine mucking field land reclamation mu. On the basis of analyzing the lithologic data of the stratum above the coal seam capable of being mined in the open pit coal mine, calculating and drawing all lithologic of the rocks in the mining boundary of the open pit coal mine based on the purpose of land reclamation soil of the open pit coal mine, particularly the distribution and equal thickness lines of weathered coal, shale and carbonaceous shale, and optimizing the technical processes and the sequence of mining and rock discharging of the open pit coal mine: excavating according to lithological characters (sandstone, shale and carbonaceous shale), transporting according to lithological characters (carrying cars or belts), and stacking waste rocks with different lithological characters in spatial positions of lithological character rock dumping yards.

(2) A method for classifying, stripping and stacking waste rocks on a recoverable coal seam based on reclamation of rock dumping field land. In the excavation process, the rocks above the coal seam capable of being mined are classified, delaminated, transported, classified and accumulated in a rock dumping field. Large stones, difficult-to-differentiate conglomerates, quartz sandstones and feldspar quartz sandstones are accumulated at the bottom of the rock dumping field; piling fine-grain sandstone and mudstone which are difficult to weather, have few clay minerals and few organic matters at the upper part of the material, filling pores formed by large stones at the lower part of the material, and mechanically compacting the materials; covering the surface of a platform, a step and a slope zone of the rock dumping field with 50-80cm thickness of shale, carbonaceous shale or weathered coal which contains organic matters and is easy to break into powder (the surface layer is preferably covered with the weathered coal, the carbonaceous shale, the shale and the mudstone in sequence).

(3) A method for reclaiming surface waste rock in a rock dumping field land. The method comprises the steps of accumulating the weathered coal, the carbonaceous shale and the like which have high clay mineral content, are easy to differentiate, break and pulverize on the outermost layer (a rock-discharging field table top, steps and slopes) of a rock-discharging field, and mechanically compacting, wherein the compaction coefficient is not less than 0.80. The thickness of the cover is 30-50cm for grassland and woodland persons after reclamation, and the thickness of the cultivated land persons is 80 cm.

(4) A method for reclaiming waste rock in a rock dumping field soil to realize soil formation and microbial formation. Mixing kitchen garbage and excrement of a mine worker restaurant with waste rock (carbonaceous shale, shale and mudstone) with the surface layer being 30cm, mixing the kitchen garbage and excrement with the waste rock (carbonaceous shale, shale and mudstone) with the surface layer being 1: 10-1: 15 according to the content of organic matters of different lithologies (weathered coal, carbonaceous shale and shale), covering the mixture by plastic cloth, stacking high-temperature compost for 20-35 days, covering the compost according to the effective thickness of 20-30 cm, then mechanically ploughing the compost to crack and pulverize the compost, and additionally, scattering compound fertilizer or leguminous green manure to increase the permeability of organic matters, nitrogen, phosphorus and potassium in soil and complete the soil reclamation. Planting trees or planting trees in pits, or broadcasting grasslands to restore grasslands, or planting crops.

The technical solution of the present invention is further described below with reference to the accompanying drawings.

As shown in fig. 3, the method for reclaiming waste rock in the dump field land based on the opencast coal mine provided by the invention comprises the following steps:

the method comprises the steps of firstly, calculating and drawing spatial distribution and equal thickness lines of all rock lithologies (coarse sandstone, fine sandstone, mudstone, shale, carbonaceous shale, weathered coal and the like) on a coal seam capable of being mined within the opencast coal mining boundary range on the basis of analyzing existing mining area coal-series stratum data, and designing, optimizing and perfecting the traditional technical method of space position and time sequence of stripping, transportation and stacking of the waste rock of the opencast coal mine.

And secondly, classifying stripping, classifying transportation and classifying accumulation of waste rocks on the stopable coal seam based on land reclamation of the rock dumping field, wherein when mechanical stripping is adopted to strip the open stopable coal seam, particular attention is paid to stripping sandstone layers, mud layers and shale layers separately, the sand layers, the mud layers and the shale layers are transported to the rock dumping field in a classifying mode, massive and difficultly differentiated gravelly sandstone, quartz sandstone and feldspar quartz sandstone are accumulated at the bottom of the rock dumping field, and sandstone blocks with the grain size larger than 50cm are accumulated at the edge of the bottom edge of the rock dumping field to build a dry rock retaining wall for stabilizing a side slope or be used for landscaping of the massive rocks of the mine. On the basis of stacking of coarse stones and sandstone, fine-grain sandstone and mudstone which are difficult to weather, less in clay minerals and less in organic matters are stacked at the upper part of the pile, pores among large stones are filled, and the piles are mechanically compacted; covering a rock dumping field platform, a step and a slope zone which are required to be reclaimed in the land with 50-80cm thick shale, carbonaceous shale or weathered coal (the surface layer is preferably covered by weathered coal or carbonaceous shale, and then shale and mudstone) which contains organic matters and is easy to break into powder. The stacking process is organically related, namely, after the sandstone is stacked in a certain range and height, the process of stacking sandstone while forming, stacking fine sandstone and mudstone on the sandstone (figure 2), and stacking carbonaceous shale on the table top and steps of the final rock dumping field is formed, and the land reclamation procedure and method of stripping while stacking and reclaiming are formed.

And step three, stacking easily differentiated, easily cracked and easily powdered carbonaceous shale or weathered coal on the surface layer (the rock-discharging field table top, steps and slope) of the rock-discharging field, wherein the stacking amount is at least designed to be used for grasslands and forest lands after reclamation, and the covering effective thickness is 30-50cm and the cultivated land thickness is 80 cm. Firstly, uniformly covering the surface layer according to the effective thickness of 30cm, further crushing, cracking and grain refining by using a mechanical plough share, and then mechanically compacting, wherein the compaction coefficient is not less than 0.80.

And step four, mixing kitchen garbage and human and animal excrements of the mine worker restaurant with waste rock (carbonaceous shale, shale and mudstone) with the surface layer being 30cm in thickness according to the content of organic matters of different lithologies (carbonaceous shale or weathered coal), mixing the kitchen garbage and the human and animal excrements with the waste rock on the surface layer, covering the surface soil with the organic matters of the carbonaceous shale or weathered coal according to the proportion of the household garbage to the waste rock being 1: 15-1: 20, preferably adopting composting for 20-35 days, covering the surface soil with the climate being 20-30 cm in effective thickness, then mechanically ploughing, crushing, cracking and powdering, and additionally, scattering compound fertilizers or leguminous green fertilizers, increasing the permeability of organic matters, potassium and soil in the soil, and completing the soil reclamation of the soil. Planting trees in seasons or in pits, or broadcasting grasslands to restore grasslands, or planting crops.

The invention relates to a rock-soil reclamation system and a technical method, wherein sedimentary rock lithology difference symbiotic with a mining coal seam is adopted, layered excavation, classified transportation and coarse weathering-resistant sandstone are stacked at the middle lower part of a rock dumping field, and argillaceous rocks, shales and carbonaceous shales with fine granularity and high clay are stacked at the upper part and the surface layer of the rock dumping field.

The invention scientifically evaluates the space distribution range, the volume, the stripped loose volume and the like of different lithologies on the coal mining layer according to the difference of lithological physical and chemical properties (rock compression resistance degree, weathering resistance degree (easy fragmentation and easy grain refining degree), clay components, organic matter content and the like) of the sandstone, mud and carbonaceous shale which are discharged on the coal mining layer and are stripped based on the aim of land reclamation of the rock dumping field of the open-pit coal mine, optimizes and designs the open-pit mining classification excavation, classification transportation, classification stacking space positions and the like, realizes the land reclamation technical method for reclaiming the waste rock and the domestic garbage land by mixing the mine domestic garbage (kitchen garbage, human and animal excrement) with the waste rock, realizes the land reclamation technical method for three-in-one of coal resource mining, waste rock resource recycling and domestic garbage harmless treatment, the key problem of restricting land reclamation in soilless and less-soil mining areas is solved, the method is a new mode of green mining development (waste rock soil formation and environmental influence minimization), the social effect, the ecological effect and the economic effect are obvious, and the method has great market popularization value.

The technical effects of the present invention will be described in detail with reference to examples.

In the example, a certain open-pit coal mine in Ullin city of Shaanxi province is taken as an example, the coal-mining carbon resource quantity of the mine can be served for 28 years, the mine is a concave open-pit mine, the mining elevation is + 1357- +1180 m, and the final boundary area of an open-pit mining pit is 32.1 ten thousand m²The deepest depth of the strip mine is 177m, and the final slope angle is 65 degrees. The thickness of the coal seam 2 layers can be mined, and the total thickness is 12-21 m. The direct roof of the strip mine coal seam is formed by gravel rock, silty mudstone, muddy silty sandstone, silty sandstone and mudstone, and the thickness of the direct roof is 1.05-31.45 m. The old top is medium and fine sandstone, siltstone and fine sandstone inclusion silty mudstone, the thickness is 0.80-40.18 m, and the mudstone includes the fine sandstone, the sandstone inclusion silty mudstone, the mudstone includes a coal line and the medium and coarse sandstone, which are mostly muded cemented. The direct bottom plate is mainly silty mudstone and carbon mudstone, the silty sandstone sandstones sandwich the coal line, the carbon mudstone and the silty sandstone are laminated, and the old bottom is the silty sandstone and the fine sandstone, and the medium and coarse sandstones and the mud silty sandstone sandwich the coal line. The firmness of the coal seam roof belongs to soft-extremely soft type, the coal seam roof is easy to break, the compressive strength is low, the coal seam roof belongs to soft type which is easy to fall, the rock is easy to soften, the rock expands when meeting water and is easy to generate bottom heave, the average compressive strength of the top and bottom rock of the two coal seams in a natural state is 6.10-81.50 MPa, the average compressive strength in a saturated state is 1.90-34.30 MPa, and the rock is soft rock. The softening coefficient average value of the bottom rock is below 0.50, and the bottom rock belongs to the rock which is easy to soften. The method comprises the steps of mechanically stripping rocks above the coal seam, leveling the stripped steps by using a front-shovel flatcar, excavating and loading the stripped waste rocks by using an excavator, transporting the stripped waste rocks by using a dump truck, and leveling the stripped waste rocks by using a bulldozerAnd (4) performing auxiliary operations such as leveling and cleaning a working surface and a transportation path. And (4) transporting the waste rocks to an external rock discharge site by a truck for discharge, and performing combined operation by a bulldozer. The occupied area of the rock dumping field is about 100 ten thousand meters²(1500 mu) and waste rock accumulation of about 2400 ten thousand meters³The maximum stacking height is 40m, the stacking is divided into two steps, and the stacking height of each step is 20 m.

Mine domestic waste landfill: the floor area is about 2000m²(3 mu), 50m 40m 2.5m specification, 5000m volume³. 340 mine staff appoint-staff, the daily life garbage produced in the year is about 56.1 tons (43.15 m) according to the daily work day of 330 days of 0.5kg per day³) (volume weight 1.3 ton/m)³). Cumulative discharge of household garbage 1122.8m in 28 years³. Because the garbage components mainly comprise kitchen garbage, plastics, paper, glass and waste batteries, the garbage belongs to mixed garbage and comprises organic pollutants and heavy metal pollutants, daily household garbage is temporarily placed in a garbage pool in an area and is cleaned and transported to a garbage landfill for compaction and burying treatment, and the garbage must be covered by pit-edge waste soil during each landfill.

The original development and utilization scheme of the mine can be seen as follows: (1) the mine development and utilization scheme focuses on the mechanical properties of rocks of a coal seam top plate and a coal seam bottom plate, and different types of rocks are evaluated without division and delineation: the distribution and thickness of sandstone, mudstone, shale, especially carbonaceous shale, weathered coal, shale which can be used as a substitute for soil for land reclamation are not separately circled. (2) The whole process of stripping, transporting and accumulating the waste rock above the coal mining layer to a rock discharge field is the mixed stripping, transporting and accumulating of the non-separated rock types. (3) The kitchen garbage and the harmful garbage are mixed into a whole by the worker household garbage, and the subsequent landfill treatment is carried out, so that the kitchen garbage which can be fermented to be used as organic fertilizer for rock dumping field land reclamation is not separately piled up and treated.

The open-pit mine is in Maowu sand, and the land utilization types of the open-pit mine such as excavation, damage and occupation are grassland, forest land and cultivated land. Wherein 1500 mu of rock field and 3 mu of domestic garbage landfill land occupy 680 mu of grassland and shrub forest land and occupy 820 mu of common cultivated land. Surface soil stripped in strip mine mining and surface soil of pressure occupied area of rock dumping field are only enough for subsequent strip mine platformsThe land and pit reclamation soil and the rock dumping field all need outsourcing soil. According to the land reclamation requirement, the mine at least needs to restore 1680 mu of rock dumping field to the grassland and cover the effective soil layer by 30cm (the compaction coefficient is not less than 0.80); the land reclamation area is 820 mu, and the thickness of the covering soil layer is not less than 0.8 m. Through investigation, the comprehensive cost (direct soil purchase cost, transportation cost and commercial land reclamation cost) of the commercial soil is 21 yuan/m³And then, the cost per mu of land reclamation and cultivated land is as follows:

the cost (Yuan) for recovering the soil on the grassland per mu is (666.7 m)²0.3 m/mu) 21 yuan/m³4200.21.26 yuan, the cost of 680 mu of grassland is 680 mu of 4200.21 is 2856142.8.8 yuan, that is, 285.61 ten thousand yuan is needed; the cost (Yuan) for recovering cultivated land per mu is (666.7 m)²0.8 m/mu) 21 yuan/m³And 11200.56 yuan, the cost (yuan) for recovering cultivated land of 820 mu 11200.56 yuan/mu 9184459.2 yuan, namely 918.45 ten thousand yuan, and the total cost for reclaiming the soil for the mine is 285.61 ten thousand yuan +918.45 ten thousand yuan 1204.06 ten thousand yuan.

That is, at present, the foreign soil is 21 yuan/m³The cost of purchasing clean soil is 1204.06 ten thousand yuan for reclaiming grassland and cultivated land in a quarry of open pit coal mining. In other words, if the shale which exists on the mined coal seam and can be used for surface soil is adopted, the corresponding land reclamation cost can be saved by 1204.06 ten thousand yuan, and the economic benefit is very obvious.

There are 200 open pit coal mines in the country, and the reclamation cost is estimated by analogy with rough estimation of the size of a rock dumping site of the coal mine (300 ten thousand tons produced per year), and the cost of purchasing earth can be saved by 200 × 1204.06 ten thousand yuan (240812 million yuan) or 24.0812 million yuan. Therefore, the invention has very good application market and huge economic benefit.

The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.