Mining_Methods_UnderGround_Mining - Mining and Blasting
Mining_Methods_UnderGround_Mining - Mining and Blasting
Mining_Methods_UnderGround_Mining - Mining and Blasting
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Mineral prospecting <strong>and</strong><br />
exploration<br />
Finding orebodies<br />
For a geologist in the mining business,<br />
exploiting an orebody is the<br />
easy part of the job. The hardest<br />
part is to find the orebody <strong>and</strong> define<br />
it. But how do you find these<br />
accumulations of metallic miner-<br />
als in the earth's crust? The mining<br />
company has to ensure that an ore-<br />
body is economically viable, <strong>and</strong><br />
needs a guarantee of ore production<br />
over a very long period of time,<br />
before it will engage in the heavy<br />
investment required to set up a<br />
mining operation. Even after production<br />
starts, it is necessary to<br />
locate <strong>and</strong> delineate any extensions<br />
to the mineralization, <strong>and</strong><br />
to look for new prospects that<br />
may replace the reserves being<br />
mined. Investigating extensions,<br />
<strong>and</strong> searching for new orebodies,<br />
are vital activities for the mining<br />
company.<br />
Prospecting<br />
Prospecting involves searching a district<br />
for minerals with a view to further operation.<br />
Exploration, while it sounds similar<br />
to prospecting, is the term used<br />
for systematic examination of a deposit.<br />
It is not easy to define the point where<br />
prospecting turns into exploration.<br />
A geologist prospecting a district is<br />
looking for surface exposure of minerals,<br />
by observing irregularities in co-<br />
lour, shape or rock composition. He uses<br />
a hammer, a magnifying glass <strong>and</strong> some<br />
other simple instruments to examine<br />
whatever seems to be of interest. His<br />
experience tells him where to look, to<br />
have the greatest chances of success.<br />
Sometimes he will stumble across ancient,<br />
shallow mine workings, which<br />
may be what led him to prospect that<br />
particular area in the first place.<br />
Soil-covered ground is inaccessible<br />
to the prospector, whose first check<br />
would be to look for an outcrop of the<br />
mineralization. Where the ground cover<br />
comprises a shallow layer of alluviums,<br />
Gold panning in the wind.<br />
trenches can be dug across the mineralized<br />
area to expose the bedrock. A<br />
prospector will identify the discovery,<br />
measure both width <strong>and</strong> length, <strong>and</strong><br />
calculate the mineralized area. Rock<br />
samples from trenches are sent to the<br />
laboratory for analysis. Even when minerals<br />
show on surface, determining any<br />
extension in depth is a matter of qualified<br />
guesswork. If the prospector's<br />
findings, <strong>and</strong> his theorizing about the<br />
probable existence of an orebody are<br />
solid, the next step would be to explore<br />
Mineral PrOSPeCTing <strong>and</strong> exPlOraTiOn<br />
the surrounding ground. Exploration<br />
is a term embracing geophysics, geochemistry,<br />
<strong>and</strong> also drilling into the<br />
ground for obtaining samples from any<br />
depth.<br />
geophysical exploration<br />
From surface, different geophysical me-<br />
thods are used to explore subsurface formations,<br />
based on the physical properties<br />
of rock <strong>and</strong> metal bearing minerals<br />
such as magnetism, gravity, electrical<br />
underground mining methods 13