annexc - Newmont Mining Corporation

Annex C4 – Water Resources Supplemental Information C4 - 33
GROUNDWATER QUALITY
Laboratory analysis for metals in groundwater samples was conducted at the SGS
Laboratory in Amsterdam, Netherlands, while all other physio-chemical constituents were
analyzed at the SGS Laboratory in Accra, Ghana. All laboratory analyses were performed in
accordance with “Standard Methods for the Examination of Water and Wastewater” of the
American Public Health Association (1995). Water quality standards or guidelines for the
parameters analyzed are presented in Table C4-4. The drinking water standard with the
lowest concentration for each parameter, if available, was used for comparison of analytical
results in statistical summaries.
Statistical summaries of chemical analyses of groundwater samples collected from
monitoring wells between 2001 and 2007 are presented in Table C4-7. These data are
compared to the water quality standards and guidelines shown in Table C4-4.
Ionic chemistry of groundwater was examined by plotting major cation and ion data on
Piper diagrams. Graphic water quality data from the statistical summaries of the monitoring
wells is presented in Figure C4-14. The Piper diagram for groundwater samples from
village wells is shown in Figure C4-15. Groundwater samples from monitoring wells are
either weakly Mg-dominant (two wells), Na-dominant (five wells), or Ca-dominant (three
wells). Bicarbonate is the dominant anion in monitoring well samples. There are no
apparent trends in major ion data from monitoring wells, although more variability in cation
concentrations is noted in monitoring well samples compared to village well samples.
Dominant anions in village well samples are bicarbonate and chloride. There is an apparent
linear trend between these anions. There are no apparent trends in cations in village well
samples. Most wells do not display a dominant cation, although a few are calcium-dominant
and even fewer are sodium-dominant. A comparison of water quality data from bored wells
and hand dug wells revealed no apparent trends.
Akyem Gold Mining Project November 2008 FINAL EIS