Thread Content
Soil and Water Conservation Plan for Mine Mining Projects and Its Characteristics Zou Zhanqiang, Chen Ziping, Guo Xinbo (Guangdong Institute of Water Resources and Hydropower, Guangzhou, 510610) Abstract: Based on the actual conditions of the limestone mining project at the New Guangzhou Cement Plant and the requirements of the Soil and Water Conservation Law, a soil and water conservation plan for this limestone mining project was formulated. The characteristics of soil and water loss control in such mining projects were analyzed. Through the implementation of this conservation plan, the degree of soil and water loss control in the project area reached over 95%, the soil erosion modulus dropped below 0.05 ten thousand tons/km2·year, the soil and water loss control ratio was 100%, the rate of retaining waste materials from the project was over 98%, the rate of restoration of disturbed land exceeded 95%, and the vegetation recovery rate was also over 95%; furthermore, the coverage rate of forest and grass vegetation was above 30%. Keywords: limestone mining project, soil and water conservation, plan, soil erosion, prevention and control, characteristics. With the development of economic construction in Guangdong Province, as well as the ’95 plan for the building materials industry in that province and the plan for restructuring the cement industry in Guangzhou, a new Guangzhou Cement Plant was planned and constructed. The limestone quarry area of the cement plant is located in Huadu District, Guangzhou City, and falls within the areas designated as key zones for monitoring soil erosion, as specified in the \"Notice Issued by the People’s Government of Guangdong Province on Designating Key Areas for Preventing and Controlling Soil Erosion across the Province\". The Soil and Water Conservation Law and related regulations stipulate that for all development and construction projects that may cause soil erosion, a soil and water conservation plan must be prepared to carry out effective measures for preventing and controlling such erosion. The purpose is to control and prevent soil erosion caused by mining; it is one of the effective measures for improving and beautifying the ecological environment in mining areas. At the same time, it helps to define, in a practical manner, the scope of responsibilities that the construction units must assume for preventing soil erosion, thereby providing a scientific basis for the supervision and inspection activities carried out by the authorities responsible for soil conservation. The implementation of soil and water conservation measures can, on the one hand, ensure the safety of the main project ； On the other hand, it can effectively control soil erosion caused by construction, reduce adverse impacts on rivers, irrigation/drainage ditches, fish ponds, and farmland in downstream areas, and at the same time prevent potential soil erosion from occurring. 1 Overview of the Project and the Project Site 1.1 Project Overview The location of the new Guangzhou Cement Plant is in Maxi Village, Xinhua Town, Huadu District, Guangzhou City. This project involves the construction of a cement production line using a new dry process pre-decomposition kiln with a capacity of 6,000 tons per day, along with related supporting facilities. It is expected that the new Guangzhou Cement Plant will begin operations around May 2005, with an annual cement production capacity of 2.274 million tons. The total investment for this project amounts to 1,821,957.1 thousand yuan. The planned start date for the limestone mining area is January 2005; it is expected to produce 2.76 million tons of limestone per year, as well as 460,000 tons of siliceous and silico-aluminous raw materials per year. The total investment amount is 105.629 million yuan. The limestone mining project is located in the Qinglonggang mining area of Wuchabu Limestone Mine, Tanbu Town, Huadu District, Guangzhou City, about 9 km from the factory site and approximately 33 km from the downtown area of Guangzhou. The mining area starts from Exploration Line 8 in the north and extends to Exploration Line 18 in the south, with a length of 2012 m and a width of 288–682 m; the lowest mining elevation is -135 m. The total mineral reserve within the mining area amounts to 109.35 million tons/40.6507 million m3 (including ore seams), which is sufficient to meet the factory’s production needs. The amount of Quaternary overlying strata that needs to be removed is 28.038 million tons/19.472 million m3; this material can be used as a silico-aluminous raw material to meet the production needs of factories. 1.2 Overview of the mining project: The mining operations include the northern mine site and the southern mine site; the mining area of the northern site is 44.15 hm2, while that of the southern site is 68.05 hm2. The construction and mining period for the northern site is 10 years, whereas it is 40 years for the southern site. Mine factory: Located on the former site of Jiangxia Village after its relocation. The mine factory is equipped with production facilities such as a comprehensive mine office, a mine material warehouse, a machine repair facility for mines, a garage, a temporary vehicle repair shop, a barrelized oil storage area, vehicle washing stations, a gas station, and a blasting materials warehouse, as well as facilities for daily living. Flood control dike: Located around the perimeter of the mining area, this dike is constructed using compacted clay; its crest elevation is +4.5m, and the width of the crest is 3m. Electrical gates are installed at the culverts through which the embankment is connected to the external water system. Stockpile area: 1.3625 million m3 of clay raw material is stored here. The project includes three stockpile areas, with a total area of 21.10 hm2; these are located within the southern mining site. 272 Mineral transport roads: Designed in accordance with the standards for Class II transport roads in open-pit mines; these are two-lane roads. Three new mineral transport roads will be constructed as part of this project – one to transport minerals from the mine pit to the crushing station, and another to transport clay to the dumping site. The total length of these roads is 1.81 km, with a road surface width of 17.5 m and a subgrade width of 21 m. The road surfaces will be made of stabilized gravel. 2 Characteristics and Prediction of Soil Erosion in the Project Area 2.1 Current Status of Soil Erosion in the Project Area The topography of the mining area consists of low mountains and hills, primarily eroded residual mounds and alluvial plains, formed from sandstone, shale, and reddish soil. The regional vegetation is growing well; it mainly consists of artificially planted vegetation and cash crop plants. The main species include lychees, longans, citrus fruits, oranges, wood** plants, banyan trees with small leaves, pine trees, green-barked bamboo, olives, bananas, pineapples, rice, and various vegetables. The vegetation is lush, with a coverage rate of over 80%. The soil erosion situation in this region is mainly found in plain areas, with some areas of gentle hills as well. Soil erosion in the plain areas is mild; it is mainly caused by agricultural cultivation and remains within the acceptable range of erosion ； In the hilly areas, due to the local emphasis on protecting the ecological environment, administrative measures such as zoning restrictions are implemented, along with extensive efforts to plant trees and grasses for greening; as a result, the vegetation is lush and soil erosion is minimal. 2.2 Characteristics of soil and water loss in the project area (1) Concentrated distribution of soil and water loss: Soil and water loss is primarily concentrated in the mining area and its vicinity. The total area of the construction site for this project is 121.47 hm2, and due to the long period of ore extraction, the time required for soil and water conservation measures is also long. (2) The volume of earthwork excavation is large, and the construction period is long, posing a risk of human-induced soil erosion. 2.76 million tons of limestone ore are mined each year, along with 460,000 tons of siliceous and silico-aluminous materials per year. Based on a mining period of 50 years, the main project will involve the extraction of 137.8 million tons (51.227 million m3) of limestone ore, and 22.95 million tons (15.938 million m3) of siliceous and silico-aluminous materials. For the flood control dike project, 47,600 m3 of earth and rock materials need to be filled; the volume of work is large and concentrated. Additionally, since some siliceous and silico-aluminous materials have been left exposed for extended periods, secondary soil erosion can easily occur. Under the climate conditions of heavy and prolonged rainfall in this area, soil erosion is a potential risk due to the scouring effect of stormwater runoff. (3) Soil and water loss occurs throughout the entire construction and mining period. Soil and water loss takes place during all stages of construction and mining. 2.3 Contents and Methods of Soil Erosion Prediction Soil erosion prediction includes the following: (1) Prediction of the area of the original landscape that is disturbed and of the land and vegetation that is damaged during the construction process ； (2) Prediction of the amount of soil, rock, and slag to be discarded during the project construction process ； (3) Prediction of the area and quantity of soil and water conservation facilities damaged during the project construction process ； (4) Prediction of the area and total amount of soil and water loss that may occur during the project construction process ； (5) Prediction of the potential hazards of soil and water loss during the project construction process. Soil and water loss prediction is carried out using a combination of qualitative and quantitative methods. The background values of soil erosion are determined through field surveys, while the predicted values are established using the analog prediction method. 2.4 Prediction Zones The prediction zones are mainly divided into: the main mining area of the project, flood control dikes, stockpiling areas, mine facilities, and temporary construction areas, etc. 2.5 Prediction of additional soil and water loss: The total amount of additional soil and water loss is estimated by determining the soil and water loss in various areas where construction takes place, based on the construction plan required by the design specifications for the mining project, as well as factors such as the geology, topography, landforms, vegetation, and rainfall in the construction area. Based on the predictions of soil and water loss in the various areas mentioned above, the baseline value for soil and water loss in this project is 15,876 tons, with the predicted total increase in soil and water loss amounting to 86,349 tons. As shown in Table 2-1. 3 Soil and Water Loss Control Plans 3.1 Principles and Objectives for Plan Formulation The formulation of these plans follows the soil and water conservation policy of \"giving priority to prevention, conducting comprehensive planning, adopting integrated control measures, adapting approaches to local conditions, strengthening management, and focusing on efficiency\". This plan is part of the limestone mining project for the new Guangzhou Cement Plant; it is subordinate to the main project and serves as a modification, supplement, and improvement to it. The formulation of the plan must comply with the **overall requirements regarding soil and water conservation and environmental protection, be in harmony with the main project and the local soil conservation plans, and soil and water conservation projects must adhere to the \"three simultaneities\" principle. 273 Table 2-1: Statistics on the Estimated Increase in Total Soil Erosion Amount. Amount of soil erosion: Serial number, Item, Area affected by soil erosion (hm2), in tons, %, Remarks. 1. Main project: 112.20, 32855, 32.7. 2. Flood control dike: 5.19, 1408, 1.4. 3. Material storage area: 21.10, 65539, 65.3. 4. Mines and factories: 2.72, 371, 0.4. 5. Temporary construction areas: 1.36, 185, 0.2. 6. Total: 121.47, 100358, 100. 7. Estimated total increase in soil erosion: 84482. The baseline value for soil erosion is 15876 tons. Through the implementation of these measures, the following goals will be achieved: (1) By implementing soil conservation measures, it will be possible to achieve a situation where there is no significant soil erosion, with the rate of soil erosion control in the project area reaching over 95%. (2) After the implementation of soil and water conservation plant measures, the soil erosion modulus dropped below 0.05 ten thousand t/km2.a, and the soil erosion control rate reached 100%. (3) The target value for the slag retention rate in construction waste is over 98% of the predicted total amount of loss. (4) The rate of disturbed land remediation reaches over 95%. (5) The vegetation restoration coefficient reaches over 95% of the area available for greening ； The coverage rate of forest and grass vegetation is over 30%. 3.2 Scope of responsibility for soil and water loss control The scope of responsibility for preventing and controlling soil and water loss is determined in accordance with the principle that \"those who develop the land are responsible for its protection, and those who cause soil and water loss are accountable for addressing it.\" The scope of responsibility for prevention and control mainly includes the project construction area and the directly affected area. The project construction area encompasses the northern mining site, southern mining site, flood control dike, material storage area, mine factory, and temporary construction areas, with a total area of 121.47 hm2. The direct impact area mainly includes the areas surrounding the main construction site, the flood control dike, the material storage sites, the temporary construction areas, and the auxiliary buildings, covering an area of 3.93 hm2. The area under the responsibility for prevention and control in this project is 125.40 hm2. 3.3 Areas for Soil and Water Loss Control: The areas designated for soil and water loss control are determined based on the characteristics of the project construction, as well as the types and severity of soil and water loss in the construction area. For this project, the soil and water conservation measures are applied in the following areas: (1) Area for control of the main project works ； (2) Flood control dike protection area ； (3) Stockyard prevention and control area ； (4) Mine plant prevention and control area ； (5) Temporary construction control area. 3.4 Soil and Water Conservation Control System Soil and water conservation measures consist of engineering measures and non-engineering measures. Engineering measures include civil engineering measures and plant engineering measures. Civil engineering measures include temporary and permanent measures, which mainly involve retaining walls, slope protection works, drainage systems, land consolidation, temporary sand bags for sediment and water control, and temporary geotextile covers ； Plant engineering measures are mainly aimed at the later stages of construction, including the greening of mine facilities, stockpiles areas, flood dike slopes, excavation slopes, construction zones, as well as ecological restoration projects following site cleanup. The non-engineering measures for soil and water conservation rely on scientific construction design, strict construction management, reasonable construction procedures, and advanced construction techniques to avoid inappropriate construction methods, reduce the volume of earthwork and stone work, as well as prevent human-induced waste of such resources, thereby avoiding soil and water loss. 3.5 Soil and water conservation engineering measures in the prevention and control zones: These measures include the excavation of drainage ditches, the filling with sandbags, their removal, the laying of plastic film, and land remediation. Based on calculations, the volume of work required for these soil and water conservation measures is shown in Table 3-1. 274 3.6 Plant-based measures for soil and water conservation in prevention and control zones Table 3-1: Statistics on the volume of work for soil and water conservation engineering measures. The principle behind implementing plant-based soil and water conservation measures is to \"protect soil and water resources and improve the environment.\" In implementation, a combination of trees, shrubs, and grasses is adopted, with local native tree species as well as mixed planting methods used for afforestation. The quantities of plant-based soil and water conservation measures in the limestone mining area are detailed in Table 3-2. 4 Soil and Water Loss Monitoring 4.1 Monitoring Items and Methods Table 3-2 Statistics Table of Engineering Quantities for Vegetation Measures for Soil and Water Conservation Vegetation measure item Unit Quantity Specification (cm×cm) Recommended seedling variety and planting method Remarks High-quality turf hm2 1.0 In bundles of 30×30 Zoysia, Bermuda – Artificially laid turf Mines and factories Ordinary grass planting hm2 32.37 (3237 kg of seeds) Sugar cane grass, carpet grass, St. Augustine grass – Artificially sown in mining sites, stockpiles areas, flood embankments, and temporary construction areas Greening trees, street trees Number 2921 Diameter at ground level × Height of seedling 1×60 Ficus microcarpa, Acacia kenii, Eucalyptus urophylla – Planted by digging holes Mines and factories, roads Soil and water conservation shelter forests Number 789 Diameter at ground level × Height of seedling 1×60 Acacia velutina, Acacia macrophylla, Eucalyptus urophylla – Planted by digging holes in temporary construction areas The main items monitored include rainfall within the area under responsibility for soil and water conservation, the area affected by soil and water loss, the amount of soil lost, vegetation coverage rate, soil and water conservation measures as well as efforts to restore soil and water conditions, and the amount of soil and water loss resulting from drainage in mining areas and its associated impacts. The monitoring methods mainly involve positioning monitoring and inspection, with a focus on monitoring during the project’s construction phase. 4.2 Layout of monitoring points: Monitoring point No. 1: North mining area ； 2# Monitoring site: South Mining Site ； Monitoring Point 3#: Flood control dike at the northern end of the North Mining Site ； Monitoring Point 4#: Flood control dike at the southern end of the South Mining Site (including monitoring the drainage in the mining area) ； Monitoring Point 5#: Material stacking area. 4.3 Monitoring Implementation Monitoring soil and water loss can provide a scientific basis for the formulation and implementation of soil and water conservation plans. It should be entrusted to units with professional technical capabilities and those qualified for monitoring ecological construction related to soil and water conservation. 5 Estimation of Investment for Soil and Water Conservation and Benefit Analysis 5.1 Estimation of Investment for Soil and Water Conservation The estimation of investment is based primarily on Document No. [2003]67 issued by the Ministry of Water Resources, as well as information regarding labor costs and unit prices for the main projects and other relevant technical data. The total estimated investment for the soil and water conservation project is 15.9324 million yuan, of which 15 million yuan is allocated to the components of the main project that serve soil and water conservation purposes, while 932,400 yuan is intended for additional soil and water conservation measures. Among the additional investment in soil and water conservation projects: the cost for engineering measures amounts to 287,100 yuan, the cost for vegetation-based measures is 230,600 yuan, the cost for temporary measures is 121,000 yuan, the cost of independent expenses is 233,600 yuan, the basic reserve fund is 7,000 yuan, the compensation fee for soil and water conservation is 53,100 yuan, and the cost for soil and water conservation monitoring is 39,600 yuan. 5.2 Benefit Analysis The comprehensive benefits of soil and water conservation include ecological benefits, as well as social and economic benefits, with ecological benefits being the most significant. (1) Ecological benefits: After the implementation of the soil and water conservation measures, soil erosion is reduced by over 95%; it is possible to effectively trap 80,300 tons of sediment. In the project area, 80% of the exposed land is covered with vegetation, resulting in the greening and restoration of that land. The mining area and its surroundings are also made more green and attractive, thereby improving the environmental landscape of the mining area. (2) Social benefits: After the implementation of the soil and water conservation plan, the waste materials generated by the project are thoroughly managed, the original landscape that was disturbed is restored, and the capabilities for retaining water and soil are improved. On the one hand, it prevents damage to water plants, villages, and surrounding farmlands downstream due to soil erosion ； On the other hand, it can improve the local landscape and promote local economic development. (3) Economic benefits: The soil and water conservation plan requires thorough protection of raw materials such as clay extracted from the mining site. The \"waste slag, waste soil, and waste rock\" generated during the construction of the mining area cannot be treated as ordinary waste; they are among the essential raw materials for cement production in cement factories. By turning waste into resources, this approach achieves two goals at once – it fulfills the functions of comprehensive soil and water conservation while also increasing economic benefits. By creating beautiful environmental landscapes, it has improved the local investment climate, attracted more investments, spurred local economic development, and contributed to the economic growth of Guangzhou. 6 Characteristics of soil and water loss control: (1) Soil and water loss is concentrated, mainly occurring in and around the mining areas; due to the long duration of ore mining, the time required to address soil and water loss issues is also long. (2) The amount of earthwork excavation is large, posing a risk of soil erosion. Since some siliceous and silico-aluminous raw materials are left exposed and piled up for long periods, secondary soil erosion can occur, necessitating preventive measures. (3) Soil and water loss occurs throughout the construction and mining phases, and control measures are also implemented throughout these same phases. (4) The soil and water conservation plan requires thorough protection of clays and other materials extracted from the mining site. The \"waste slag, waste soil, and waste rock\" generated during the construction of the mining area cannot be treated as such waste like in other types of projects; they are among the raw materials necessary for cement factories to produce cement. This post was last edited by hesonchang214 on 2009-4-6 08:40.]