Physicochemical properties of pit-water from ishiagu lead/ zinc (Pb/Zn) mine as an index for alkaline classification of the mine drainage

The nature and chemical composition of mine pit-water was investigated in ishiagu lead/zinc (pb/zn) mine in southeastern, nigeria. laboratory determination of some physicochemical parameters namely, temperature, total dissolved solids (tds), conductivity , chloride, ph, alkalinity, hardness, sulphate and dissolved metal constituents like calcium and magnesium were assessed in the three mine pits using standard methods. the results showed that ishiagu pb/zn mine is slightly acidic with moderate levels of dissolved metal constituents. seasonal variation observed in the parameters indicate higher levels for ph (6.7-8.1), alkalinity (36.4--115.3mg/l) and sulphate (6.8-84.4) in the wet season when compared with corresponding values, ph (6.1-7.3), alkalinity (31.3- 98.4mg/l) and sulphate (6.1-78mg/l) in the dry season. the consistently the higher levels of ph, alkalinity, hardness, calcium, magnesium, total dissolved solids (tds) and conductivity in more than 66% of the mine pits (mine 1and mine 3) investigated across the season is an indication of changing state of the mine pit-water to more alkaline mine drainage. this phenomenon is attributable to preponderance and buffering effect of carbonate minerals in the area.