Potential acid rock drainage from
the destruction of metalliferous sulph-
ides is recognised as a critical factor
in the design and economics of any
mining venture. While this realisation
is relatively new, mining companies
have embraced the issue with the aim of
scientifically quantifying the magnit-
ude of the problem, specific to indiv-
idual properties.
Coinciding with the development
of the open pit mine at Porgera, a
comprehensive assessment of the potent-
ial for the formation of acid rock
drainage was initiated in 1991. Detail-
ed study of the mineralogical charact-
eristics of all rock types, along with
extensive test work to determine the
maximum potential of rocks to generate
and consume acid (known as acid base
accounting or ABA), has been conducted.
Correlating this with the known and
interpreted geology of the open pit has
indicated a strong relationship between
rock type, sulphur content and the acid
base character. This relationship is
used daily as a simple, cost effective
means for classification and management
of the variety of material types
produced from the minincx operation.