Dump leaching at Teller in its present form began in the fourth
quarter of 1988 as an adjunct to milling operations. Initial plans
called for a dedicated dump leach facility capable of processing
ore at an annual rate of 2.0 million tonnes. Construction of a
dump leach pad, collection and process ponds, carbon adsorption
system, elution plant as well as reagent addition and ancillary
facilities was initiated in mid-1988. During the course of construction, additional reserves were
proven. As a result, design throughput was increased to
4.0 Mtpa. Leach pad capacity and solution supply systems were
upgraded to handle the larger throughput. However, the carbon
adsorption/elution facilities were not upgraded due to space
limitations. During 1990 it was decided to expand the dump leach
operation to 6.0 Mtpa. Construction of a second leach pad was
required which was initiated in early-1991. Plans were again
upgraded prior to completion to a target annual throughput of
10.0 million tonnes was. A further two leach pads have been
constructed. The first of these being completed during the latter
part of 1992. Construction of the latest and largest pad
commenced early in 1994.