mining tailings versus orebodies

Many of the financial risks involved in mining revolve around the problems of finding, characterising, measuring, and mining ore. There are many highly variable characteristics of ore deposits that can result in disastrous cost over-runs or negative profitability. These characteristics include the continuity of the ore, the uniformity, the grade, the dip angle, the depth, the haulage distance, the geotechnical stability of pit slopes and underground openings, and so on.

By comparison, consider the risks that have been avoided or minimised in Envirogold's plan to extract gold and silver from tailings, such as at Las Lagunas:

1. Tailings are usually of far more homogeneous grade than ore bodies. Don't underestimate the significance of this: many a mining venture has failed because there proved to be little or no ore between the drill holes.

2. Tailings have already been crushed.

3. Tailings storage locations are usually more centralised and closer to infrastructure than ore bodies. There is water and grid power available at Las Lagunas.

4. In general, the reprocessed tailings can be disposed of to a pre-existing storage.

5. There's no need to construct pits or tunnels to mine tailings. An end-loader typically suffices. There is little or no overburden to strip.

There are of course other sources of risk, but it's nice to know that at least some risks associated with mining either don't apply to Envirogold, or are significantly diminished.