annexc - Newmont Mining Corporation

Annex C4 – Water Resources Supplemental Information C4 - 16
Ionic chemistry of surface water was examined by plotting major cation and ion data on
trilinear, or Piper, diagrams. The diagram for the Pra River and its tributaries using water
quality data from the statistical summaries is presented in Figure C4-6. The Piper diagram
for the Mamang River and tributaries is shown in Figure C4-7.
Bicarbonate is the dominant anion in surface water samples from the Pra River, Mamang
River, and their tributaries. None of the major cations (i.e., calcium (Ca), magnesium (Mg),
sodium (Na), and potassium (K)) used for the analysis was dominant. There is more
variability in the ionic chemistry of samples from the Mamang River compared to Pra River
samples; however, the variability is low in both drainages. The following trends in ionic
chemistry were noted:
• Relative increase in sodium in dry season samples compared to wet season samples.
This may be due to an increase in the influence of groundwater chemistry during low
surface water flow conditions.
• In tributary streams, there is a relative increase in bicarbonate in dry season samples
compared to wet season samples. This trend is not apparent in main stem samples
from the Pra River and Mamang River.
• An apparent linear trend exists in the cation data between sodium and
calcium/magnesium, which may be due to cation exchange reactions or the relative
influence of groundwater on river water chemistry.
SPRINGS AND SEEPS
For the 10 spring/seep locations established in 2007 by Clear Creek Consultants (2008c),
three sampling events were conducted during early-March, late-July, and mid-November.
Statistical summaries of chemical analyses of spring/seep water samples collected in 2007 are
presented in Table C4-6. These data are compared to the water quality standards and
guidelines shown in Table C4-4.
A trilinear Piper diagram for all of the spring/seep water quality data using the statistical
summaries is presented in Figure C4-8. Bicarbonate is the dominant anion in the samples.
None of the major cations (i.e. Ca, Mg, Na, K) used for the analysis was dominant. An
exception to this generalization is the sample from Adentosu (ADET-1) which has a
dominant sulfate anion.
Akyem Gold Mining Project November 2008 FINAL EIS