De-watering is the removal of water
from a saturated medium caused by
the pumping of groundwater from wells,
or excavation into the medium allowing
groundwater to drain freely to the
void. This may lead to groundwater
inflow from surrounding areas, down
a gradient created by the de-watering.
Very hard quartz that makes sparks. GEOLOGY
- a very hard greyish-black
fine-grained form of quartz that occurs
widely as nodules and bands in chalk.
Structure of an area. The study
of the structure of the Earth or another
planet, in particular its rocks, soil,
and minerals, and its history and origins.
An exploratory program directed to
the examination of rock sediments
obtained via boring or drilling by
inspection of surface outcroppings.
Mining by surface excavation. Mining
in which excavation work takes place
on the surface and minerals are extracted
by removing the top cover in strips.
Unconsolidated surface material
such as earth, sand and boulders,
overlying and seperating the coal
A piezometer is a non-pumping bore,
generally of small diameter, that
is used to measure the elevation
of the water table or potentiometric
surface. A Piezometer generally
has a short well screen through which
water can enter.
Piezometric water level (or
Piezometric water level (or potentiometric
surface) is the level to which water
will rise in tightly cased wells. If
the head varies significantly with
depth in the aquifer, then there may
be more than one potentiometric surface. The
water table is a particular potentiometric
surface for an unconfined aquifer.
Relating to earthquakes. Relating
to or caused by an earthquake or earth
A subcrop is that part of a geological
formation (eg a coal seam) that is
close to the surface but is not outcropping. It
is usually under the soil profile
or alluvial sediments.