Environmental Aspects of Phosphate and Potash Mining

Environmental Aspects of Phosphate and Potash Miningways, during loading and unloading operations, atconveyor transfer points and during the stacking ofstockpiles and reclamation operations. Exhaust gasesand particulates are largely produced by the operationof transport.A variety of dust control techniques are used, as discussedin Section 3.1.Equipment emissions are reduced by the use ofexhaust filters, regular equipment maintenance programsand replacing old engines with new, moreefficient and cleaner models.Watershed ProtectionRegulations in Florida to protect watersheds from disturbancehave restricted the development offloodplains, streams and rivers. Accordingly, phosphaterock mining operations must establish bufferzones and work around these features. However, onoccasions crossings may have to be constructedacross them to facilitate access to mining areas.Development of a new mining area at the IMCPhosphate Four Corners operation in central Floridarequired the construction of a river crossing. This wasdesigned to allow vehicle and equipment access andthe passage of several large diameter slurry pipelinesbetween the mining area and the beneficiation plant.The design has a number of features to mitigatepotential environmental impacts.Culverts have been placed under the earthen vehiclecrossing, allowing normal river flow to be maintained.Silt traps contain minor erosion sediments from thecrossing.During heavy rain, the water level rises and passesover the crossing. Surfacing the vehicle roadway withcoarse aggregate and the planting of grass on adjacentroadside areas has reduced the potential forerosion.The large-diameter ore slurry pipelines have beenplaced alongside the crossing roadway and elevatedto allow water to pass underneath. In the event of failure,the pipes are double lined at the crossing,discharging to a containment pond at one end, whilean automated monitoring system alerts management.Watershed protection is an integral part of the crossingdesign. The construction of a stable, non-erodingriver crossing and the installation of a monitoring andcontainment system in the event of a slurry pipelinefailure prevent contamination of downstream areas.Transport of Ore and Concentrate by SlurryPipelineThe transport of ore and concentrates as a slurry (amixture of water and ore particles in suspension) hasbenefits such as less road transport congestion,reduced vehicle exhaust emissions and the eliminationof sources of dust emission. Slurry pipelines areused at a number of operations worldwide.In Florida, the phosphate mining operations of companiessuch as Cargill Fertilizer Inc. and IMCPhosphate use high-pressure water jets to convert theore excavated by the draglines into a slurry which canbe pumped to the beneficiation plants through largediameter pipelines.In Brazil, Fertilizantes Fosfatados S.A. (Fosfertil) uses a125 kilometre long pipeline to transport phosphaterock concentrate slurry from the beneficiation plant atthe Tapira mining complex to the fertilizer processingcomplex at Uberaba.Uberaba Fertilizer processing complex - Fosfertil, BrazilPhosphate rock concentrate slurry tanks and pumping -Fosfertil, BrazilSlurry pipelines require significant quantities of water.This may present issues in areas of limited resources.Recycling or re-use of the water for other processesmay be possible.