Mineral Processing Engineering

The scaling technique significantly reduces computation time below that required for streamline modeling and simplifies desk-top calculations. The scaling technique applies to any flow processes (tracers, nonadsorbing species, or displacements) where chromatographic spreading/sharpening overrides physical dispersion.

Description of Streamline-Material Balance Model

In order to develop a standard for measuring the scaling technique, we present a brief description of the streamline-material balance model. Both restoration and leaching models are based on the coupling of streamlines with material balances.

The travel time T of a fluid particle along a streamline is

where Δtk is the travel time over a finite increment

and M is the total number of increments required for the streamline to traverse from injector to producer. Thus, the length of the streamline is

L = MΔl……………………………………………………………………….(3)

Since mobilities are constant, the flow rate associated with each streamline is constant and given as

where Qp is the production well flow rate and Ns is the number of streamlines associated with each producer. Since streamlines are traced backward, the production rate, instead of injection rate, is used in computing the streamline

The Tonopah silver mining district, was first discovered in the summer of 1900 and primitive small scale mining operations had started by the end of the year.

Millers Tailings Mineralogy

Mineralogical studies showed that the principal gangue minerals in the Millers tailings were, in order of abundance, quartz, feldspar and sericite. Hornblende, chlorite and a carbonate, possibly rhodocrosite, were also identified.

Chemical analysis of samples showed that, in addition to silver and gold, the Millers tailings contain 1.3-1.6% iron and 0.3-0.5% manganese. Other metals were present in insignificant quantities, viz., Copper – 0.01% or less, Zinc – 0.1% or less, Arsenic 0.05% or less, and Molybdenum, Tellumium, Mercury, Cadmium, Antimony all less than 0.001%. The samples showed variable organic content between 0.03% and 0.3%.

Development Test Work of the Sulfurous Acid Pre-Leach Process at Millers

Test work had shown that only 40-50% of the silver values could be leached by conventional cyanidation from the Tonopah Mining Company tailings, whereas upwards of 65% could be extracted from the Tonopah Belmont Development Company tailings.

Only minor improvements in silver extraction could be attained by increasingly fine grinding, additional cyanide addition and extension of the leach residence time. It was, however, shown that carbon-in-leach had