Related by context. Frequent words. (Click for all words.) 56 taconite 56 bentonite 55 tailings 55 mine tailings 55 frac sand 54 mill tailings 54 pelletizing 53 evaporation ponds 53 silica sand 53 quicklime 51 sulfide 51 Vermiculite 50 gravel 50 fly ash 50 chlorides 50 contaminated soils 50 silica 50 ore 50 Leaching 50 lignite coal 49 iron oxides 49 sediment 49 crushed limestone 49 contaminated soil 49 Taconite 49 trona 48 pelletized 48 Tailings 48 wood preservatives 48 hydrofluoric acid 48 iron manganese 48 manganese 48 arsenic mercury 48 hydroxide 48 iron ores 48 sodium carbonate 48 fluorspar 48 ores 48 brine 48 leaching 48 diatomaceous earth 48 sludge 48 Niobium 48 quarries 48 contaminating groundwater 47 ferrous metal 47 asphalt pavement 47 tailing ponds 47 limestone 47 Sediments 47 sediments 47 cobalt 47 roadbeds 47 smelting 47 gravel pits 47 sulphide ore 47 metals 46 polluted groundwater 46 slag 46 sulphates 46 Hoyt Lakes 46 copper nickel 46 coarse sand 46 absorbents 46 salts 46 sulphate 46 zeolites 46 glacial till 46 soda ash 46 bitumen 46 byproducts 46 borate 46 Sediment 46 heap leaching 46 metallic minerals 45 sulfate 45 crumb rubber 45 dredge spoils 45 chlorinated solvents 45 coal tar 45 gravels 45 minerals 45 contaminated sediments 45 slurries 45 apatite 45 mercury arsenic 45 soils 45 limestone quarry 45 perlite 45 quarry 45 dewater 45 suspected carcinogen 45 tributary streams 45 mineral salts 45 carbonaceous 45 phosphate fertilizer 45 sulfuric acid 45 cobalt nickel 45 asphalt 45 cullet 45 dissolved solids