MINING AND METALLURGY INSTITUTE BOR ISSN: 2334-8836 UDK: 622 UDK: 622.27:504.06(045)=20 DOI:10.5937/MMEB1302097L Ružica Lekovski*, Miomir Mikić*, Daniel Kržanović* IMPACT OF THE FLOTATION TAILING DUMPS ON THE LIVING ENVIRONMENT OF BOR AND PROTECTIVE MEASURES** Abstract In the southeastern Serbia, in the area of the municipality Bor, there are three flotation tailing dumps: FTD Bor, FTD RTH (the ore body H) and FTD Veliki Krivelj. The Flotation Tailing Dump Bor is abandoned, partly reclamated. The other two are active flotation tailing dumps. All three flotation tailing dumps are serious polluters of air, water and soil. The affected zones by dust from these tailing dumps threat large areas in a direction of dominant wind from the northwest direction. The affected areas by the impact zone of dust from: the Bor Flotation Tailing Dump amount to 18,361,074 m2, flota- tion tailing dump of the ore body H, 3,713,408 m2 and Flotation Tailings Dump Veliki Krivelj, 16,077,805 m2. The most effective measure against dust rising from dry areas by the wind is the use of reclamation with the phases of technical, agrotechnical and biological reclamation. Keywords: flotation tailing dumps, environmental protection, accidents, flood wave, affected zone INTRODUCTION Preparation of the low grade copper Various forms of construction the flota- ore in the Flotation Plant Bor and Flota- tion tailing dumps were used for the flota- tion Plant Veliki Pine Krivelj and concen- tion tailing dumps Bor, RTH and Veliki trations of useful components in the form Krivelj. of copper concentrate provides large The oldest Flotation Tailing Dump Bor amounts of flotation tailings, which re- was initially built as a valley type in the Bor quires occupation of large areas for their stream, then the combined valley and plain storage (disposal). Thereby, concentrate type of construction were used for upgrading and tailings are obtained in the mixture the tailing dump. with water in a form of pulp. Concentrate, The Flotation Tailing Dump RTH was as useful component, is dewatered and originally built as a deep type of tailing stored in bins in the plant for further pro- dump in the excavated area of the open pit cessing in the Copper Smelter Bor, while RTH, and then the radial method was used tailings is transported to the disposal place for upgrading, nowadays the outgoing predominantly by hydraulic plastic pipes method. The Flotation Tailing Dump Veliki (FTD RTH) and gravity using the concrete Krivelj is the valley type, and dams were channels (FTD V.Krivelj). built by ingoing method, while the upgrai- * Mining and Metallurgy Institute Bor, 19210 Bor, Serbia ** This work is the result of Project No. 33021 "Research and Monitoring the Changes of Stress-strain State in the Rock Massif "in-situ" Around the Underground Rooms with Development a Model With a Special Review to the Tunnel of the Krivelj River and Jama Bor", funded by the Ministry of Education, Science and Technological Development of the Republic of Serbia No. 2, 2013 97 Mining & Metallurgy Engineering Bor ding is done using the outgoing method. For Disposal of tailings into the accumula- disposal of flotation tailings, resulting in the tion space is performed depending on the processing of ore, the space obtained by field morphology around the tailing dump, damming the Veliki Krivelj river valley is the position of sedimentary lake, length of used (1). Tailings was delayed by in-depth beache, and it is aimed to maximum utili- type without separating the solid from liquid zation of available space. In pump dis- phase, while in the partitioned areas with charging into accumulation space, it is dams and peripheral dikes, the cycloning of taken into account, in the operational tailings and separate disposal are done. Only work, that its jet does not mechanically hydrocyclone overflow is deposited into the damage the foot of inside dam slope. accumulation area, and the hydrocyclone A lake is formed inside the flotation sand on dams, which also serves as the ma- tailing dump in which the sedimentation terial for construction of dams and peripher- of slime from pulp and separation of pure al embankments to the designed level. In water are performed, where the highest order to realize the new extension of flota- point in relation to the dam elevation must tion tailing dump, it is necessary to previous- be reduced for 3.0 to 5.0 m depending on ly build the new facilities for deviation the the catchment area around the flotation Krivelj River, located in the zone of flotation tailing dump. Clarified water from the tailings (2). In this way, the space will be lake is returned back into the process by provided for permanent disposal of flotation pumps floating on a raft in the lake. tailings. (2) Flotation reagents, representing differ- Because of the reliability of service ent chemical compounds, are used in the and safe exploitation of predicted space of technological process of flotation concen- flotation tailings in order to protect the tration, including: xanthogenates, alkali environment, initially after start the con- metals, dithiophosphates, polyglycols and struction of tailing dump with artificial lime, which is used for pH value control barriers of dams and dikes, the followings of technological water. Flotation reagents were built: are absorbed on the surfaces of particles, - Basic (starting or initial) dam of solid and a part remains in the water in dis- material (soil, sand or crushed stone) solved and dispersed state. In addition to which is the support and filter base, water, which is transported into the lake - Drainage system in the basement of from the Flotation Plant with flotation starting dam with collector for ac- tailings, the lake is also filled with pure ceptance the inflow water and de- water from the precipitation within the watering the dam around the con- basin of flotation tailing dumps (rain and tours of the landfill, snow melting). - System for hydro transport, slime The leachate from tailing dump is col- cycloning,construction and filling of lected in front of the protective dam over the dam and peripheral dyke of the flo- drainage system and returned back in the tation tailing dump and disposal of fine lake. Water inflow through dam is con- slime and water into sedimentary lake, trolled. Untimely control of inflow water - System for evacuation of clarified leads to softening of embankment foot and water in the flotation process, dam accident. Part of the water from tailing dump is - System for acceptance the inflow and also lost by infiltration - groundwater re- overflow water and their return into charging or evaporation. The excess of sedimentary lake or reuse. Therefore, clarified water, corresponding to the third their proper sizing, design and solid class of water stream from the flotation construction are very important. lake, is discharged through the overflow No. 2, 2013 98 Mining & Metallurgy Engineering Bor body and collector into the river (eg. FTD downstream of the town of Bor. Accidents V. Krivelj). In case of lack of water in the or incidents on the flotation tailing dumps flotation lake (minimum water for normal are caused by natural disasters, technical operation of the Flotation Plant), the re- failures, and the combination of both (3). quired amount of water is taken from the On this occasion they result into ocurrence Bor Lake (FTD RTH) and the Krivelj of dangerous threats to the environment River (FTD V. Krivelj). where they pollute the water, soil, plants, destroy the habitat of animals and flood CONSTRUCTION OF THE DAM the houses of people (3). Many environmental accidents hap- Construction of dams pened in RTB Bor due to the damages on the flotation tailing dumps with pollution Hydrocyclones are installed along the of rivers, soil and plants. Damages of ac- dam on the fixed and stable stands at suffi- cidents on the flotation tailing dumps hap- cient height of the existing dam crest eleva- pened due to the technical failures and tion or on mobile platforms, which can be natural disasters. moved in any direction. During construction Causes of accidents in the Flotation of the dam, the sand is quite compact. If this Plant Bor and discharge the tailings into is not achieved, the additional compaction of the Bor River in the seventies of the last sand or rolling are applied. century were classified in a group of tech- nical failures (inadequate design solutions, Stability of the dam unreliability of device operation in the production system and the lack of control The dam is the main object of flotation and breaching the rules). Frequent power tailing dumps, so its stability is vey im- cuts during this period caused the failure portant. The basic condition for dam stabil- of equipment, used in the Flotation Plant ity is that the line of inflow water (depresion and flotation tailing dump Bor for disposal line) should not be closer to the outer slope of tailings, so the flotation tailings was of the dam. The inflow water line is obtained discharged into the Bor River. by reading the water level in the built-in Occurrence of sudden flooding waves piezometers. When the inflow water line with hazardous chemical contamination approaches to the outer slope of dam, the has led to the destruction of flora and fau- rehabilitation of dam drainage system has to na in the Bor River, and the arable areas be done immediately. The task of drainage on the banks of the river were flooded and system is to collect and safely take the water the flotation tailings were deposited on that passes through the body of dam. The them in the sediment higherr than 50 cm.