Mining engineering is an engineering discipline that involves the practice,
the theory, the science, the technology, and application of extracting and
processing minerals from a naturally occurring environment. Mining engineering
also includes processing minerals for additional value. Mineral extraction is
essential to modern society. Mining activities by their nature cause a
disturbance of the environment in and around which the minerals are located.
Mining engineers must therefore be concerned not only with the production and
processing of mineral commodities but also with the mitigation of damage to the
environment as a result of that production and processing.
History
of mining engineering
Since the beginning of civilization
people have used stone and ceramics and, later, metals found on or close to the
Earth’s surface. These were used to manufacture early tools and weapons. For
example, high quality flint found in northern France and southern England were
used to set fire and break rock. Flint mines have been found in chalk areas
where seams of the stone were followed underground by shafts and galleries. The
oldest known mine on archaeological record is the "Lion Cave" in Switzerland.
At this site, which radiocarbon dating indicates to be about 43,000 years old, Paleolithic
humans mined mineral hematite, which contained iron and was ground to produce
the red pigment ochre.
The ancient Romans were innovators
of mining engineering. They developed large scale mining methods, perhaps most
notably the use of large volumes of water brought to the mine head by numerous a
que duct for hydraulic mining. The exposed rock was then attacked by fire-setting
where fires were used to heat the rock, which would be quenched with a stream
of water. The thermal shock cracked the rock, enabling it to be removed. In
some mines the Romans utilized water-powered machinery such as reverse overshot
water wheel. These were used extensively in the copper mines at Rio Tinto in
Spain, where one sequence comprised 16 such wheels arranged in pairs, lifting
water about 80 feet (24 m).
Black powder was first used in
mining in Hungary (present-day Slovakia) in 1627. This allowed blasting of rock
and earth to loosen and reveal ore veins, which was much faster than
fire-setting. The Industrial Revolution saw further advances in mining
technologies, including improved explosives and steamed-powered pumps, lifts,
and drills as long as they remained safe.
Salary
and statistics
In the United States, there are an
estimated 6,630 employed mining engineers. The mean yearly salary for a mining
engineer in the U.S. is $90,070. You can relatively look at your country and
determine it with respect to economic viability.
Mineral
exploration
Mining engineers are consulted for
virtually every stage of a mining operation. The first role of engineering in
mines is the discovery of a mineral deposit and the determination of the
profitability of a mine.
Mineral
discovery
Mining engineers are involved in the
mineral discovery stage by working with geologists to identify a mineral
reserve. The first step in discovering an ore body is to determine what
minerals to test for. Geologists and engineers drill core samples and conduct
surface surveys searching for specific compounds and ores. For example, a
mining engineer and geologist may target metallic ores such as galena for lead or
chalcopyrite for copper. A mining engineer may also search for a non-metal such
as phosphate, quartz, or coal.
The discovery can be made from
research of mineral maps, academic geological reports or local, state, and
national geological reports. Other sources of information include property
assays, well drilling logs, and local word of mouth. Mineral research may also
include satellite and airborne photographs. Unless the mineral exploration is
done on public property, the owners of the property may play a significant role
in the exploration process, and may be the original discoverer of the mineral
deposit.
Mineral
determination
After a prospective mineral is
located, the mining engineer then determines the ore properties. This may
involve chemical analysis of the ore to determine the composition of the
sample. Once the mineral properties are identified, the next step is
determining the quantity of the ore. This involves determining the extent of
the deposit as well as the purity of the ore. The engineer drills additional
core samples to find the limits of the deposit or seam and calculates the
quantity of valuable material present in the deposit.
Feasibility
study
Once the mineral identification and
reserve amount is reasonably determined, the next step is to determine the feasibility
of recovering the mineral deposit. A preliminary study shortly after the
discovery of the deposit examines the market conditions such as the supply and
demand of the mineral, the amount of ore needed to be moved to recover a
certain quantity of that mineral as well as analysis of the cost associated
with the operation. This pre-feasibility study determines whether the mining
project is likely to be profitable; if it is then a more in-depth analysis of
the deposit is undertaken. After the full extent of the ore body is known and
has been examined by engineers, the feasibility study examines the cost of
initial capital investment, methods of extraction, the cost of operation, an
estimated length of time to payback, the gross revenue and net profit margin,
any possible resale price of the land, the total life of the reserve, the total
value of the reserve, investment in future projects, and the property owner or
owners' contract. In addition, environmental impact, reclamation, possible
legal ramifications and all government permitting are considered. These steps
of analysis determine whether the mine company should proceed with the
extraction of the minerals or whether the project should be abandoned. The
mining company may decide to sell the rights to the reserve to a third party
rather than develop it themselves, or the decision to proceed with extraction
may be postponed indefinitely until market conditions become favorable.
Mining
operation
Mining engineers working in an
established mine may work as an engineer for operations improvement, further mineral
exploration, and operation capitalization by determining where in the mine to
add equipment and personnel. The engineer may also work in supervision and
management, or as an equipment and mineral salesperson. In addition to
engineering and operations, the mining engineer may work as an environmental,
health and safety manager or design engineer.
The act of mining required different
methods of extraction depending on the mineralogy, and location of the
resources. Characteristics such as mineral hardness the mineral stratification and
access to that mineral will determine the method of extraction.
Generally, mining is either done
from the surface or underground. Mining can also occur with both surface and
underground operations taking place on the same reserve. Mining activity varies
as to what method is employed to remove the mineral.
Surface
mining
Surface comprises 90% of the world's
mineral tonnage output. Also called open pit mining, surface mining is removing
minerals in formations that are at or near the surface. Ore retrieval is done
by material removal from the land in its natural state. Surface mining often
alters the land characteristics, shape, topography and geological make-up.
Surface mining involves quarrying
which is excavating minerals by means of machinery such as cutting, cleaving,
and breaking. Explosives are usually used to facilitate breakage. Hard minerals
such as limestone, sand, gravel, and slate are generally quarried into a series
of benches.
Strip mining is done on softer
minerals such as clays and phosphates are removed through use of mechanical
shovels, track dozers, and front end loaders. Softer Coal seams can also be
extracted this way.
With Placer mining minerals can also
be removed from the bottoms of lakes, rivers, streams, and even the ocean by
dredge mining. In addition, in-situ mining can be done from the surface using
dissolving agents on the ore body and retrieving the ore via pumping. The
pumped material is then set to leach for further processing.
Hydraulic mining
is utilized in forms of water jets to wash away either overburden or the ore
itself.
Mining
process
Explosives are used to break up a
rock formation and aid in the collection of ore in a process called blasting.
Blasting utilizes the heat and immense pressure of the detonated explosives to
shatter and fracture a rock mass. The types of explosives used in mining are high
explosives which vary in composition and performance properties. The mining
engineer is responsible for the selection and proper placement of these
explosives, in order to maximize efficiency and safety. Blasting occurs in many
phases of the mining process, such as development of infrastructure as well as
production of the ore.
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