Open-Pit Mine Soil Amendment By Coal-Based Compost Method

Mining is an environmental destruction activity that results in the removal of the surface layer of the soil and the removal of nutrients beneficial to the survival microorganisms and growth of plants from the soil.These degradations dangerously affect not only the lives of humans,but also affect the lives of all other living beings in the same way.Thus,the best way to mitigate the effects of environmental degradation caused by mining is to do post-mining restoration work.This research is part of this restoration framework.Another problem of daily life is environmental pollution through poor waste management.Most of these wastes are incinerated,which leads to the release of a significant amount of greenhouse gases that actively participates in the global warming process,or these wastes are buried in the ground,which leads to the pollution of soil,waterways and groundwater.One of the best ways to treat these wastes is composting and it’s this method that has been used in this thesis as a method of restoration.Therefore,the purpose of this research is to use the composting method to improve the soil of the West pingzhuang open-pit mine to restore the ecosystem destroyed by mining activity.Overall,although the experiment was successful,there are factors,if not carefully considered,that can cause the overall operation to fail or hinder their success.After the composting process,which lasted 28 days,the important characteristics of the compost were:TOM=28.46%,TOC=16.55%,TN=0.95%,TP=0.076%,PK=1.43%,p H=7.1,EC=3.32 m S/cm and carbon/nitrogen ratio was 17.42.Since there was a real doubt about the possible use of lignite,a first test was carried out on the soil not improved and on the soil improved with lignite-based compost.On the soil not improved,TOM=0.96%,p H 6.8,alfalfa germination rate was 80%and 10 days after seeding,plant height was 2.4 cm while on soil improved with lignite-based compost,TOM=14.92%,p H of 5.4,alfalfa germination rate of 50%and plant height to 1.6 cm.Since the results were not satisfactory,5 other treatments were implemented.The unimproved soil treatment was represented by T1,the mixture between compost and soil in proportions1:1,1:2 and 1:3 were respectively represented by T2,T3 and T4 and finally a 5th treatment consisting of soil improve with chemical fertilizer noted by T5 were prepared and arrogated for 5 days to 50 ml of distilled water and 25 ml of distilled water for another 5 days after seeding seeds.20 days after the preparation of the 5 treatments,the tests showed that T3 consisting of 1/3 compost and 2/3 soil was theoretically the best improvement plan for the site.On this T3,the bulk density was 0.93 g/cm~3 while the soil without improvement T1 had a bulk density of 1.41 g/cm~3.10 days after the last watering,the water content of T3 was 24.75%while T1 had only 12.93%.The main nutrient contents on T3 were:TOM=10.70%,TOC=6.22%,TN=132 mg/kg,TP=10.56mg/kg and TK=198 mg/kg whereas in T1,TOM=0.96%,TOC=0.56%,TN=45 mg/kg,TP=3.6 mg/kg and TK=67.5 mg/kg.The electrical conductivity on T3 was 1.95 m S/cm while it was only 0.54 m S/cm on T1.Although T3 was theoretically better,only plants could confirm this status.So three crops including wheat,corn and alfalfa were used.But based on the germination rate,wheat proved to be the most suitable plant for this restoration although natural revegetation is chosen as a method of revegetation in this thesis.20 days after sowing the 10 wheat seeds on each treatment,on T3,the wheat plants reached a maximum size of 27 cm,a maximum root length of 13 cm and an arian and underground biomass of 4.02 g while on T1,the maximum plant size was 24.5 cm,the maximum root length was 9 cm and the arian and underground biomass was 2.18 g.On T3,the roots were still much more branched than on T1.During the observation period,the plants were better in all respects on T3 than on T1.And finally an on-site improvement plan has been established.This plan summarizes all the operations carried out in the field such as remodeling the topography of the site,decompaction of the site,application of fertilizers to the soil of the site,seeding or planting and subsequent plant maintenance work.These test and analysis results showed that:(1)Combined composting of chicken waste,household waste,wheat straw and fallen leaves can produce compost of sufficient quality to improve degraded and depleted soils by mining.(2)In the composting process,the adequate frequency of ventilation that was done every 4 days,the daily control of the water content and the installation of a temperature maintenance device around the compost silo made it possible to considerably shorten the composting time to 28 days despite the influence of freshness which is an inhibitory or delaying factor of the aerobic decomposition process.(3)With the types of wastes used in the experiment,this lignite-based compost is no better suited in the ecological restoration of the site because the soil of the site is also acidic just like lignite.However,if it’s to be used,it must be used at very low doses.There are 35 figures,11 tables,105 references in the thesis.