A new face drilling rig for narrow tunnels and ... - Advanced Mining

• Sound protection by terrain topology, buildings and cultivation
of plants
• Avoid acoustic start warnings or have it individually adapted
to the background noise level +10dB
• Avoid great falls of material, make provision for material
upholsters, if necessary
Some simple rules:
• In the free field, the sound pressure level measured
reduces by 3dB with a doubling of the distance from the
source. (This way, it is made possible to check whether
there is a free field condition).
• A difference in sound power level of 3dB corresponds
to a halving or doubling of the sound power.
• If the speed of the gearbox is halved, the sound power
level will reduce by approx. 6dB.
• The doubling of the gearbox torque results in an
increase of the sound power level by approx. 3dB.
Conclusion
Today, it is enabled plants to be calculated and planned
with regard to their sound emission. On account of the
complex evolutionary and propagation mechanisms of
sound, however, these prognoses are only considered
reference values. That is why independent measures on
plants already built are absolutely necessary to be capable
of understanding acoustic particularities of machines and
plants.
The operators must also aware of the fact that the
realization of low-noise machines and plants will not be
possible cost-neutral.
Issue 04 | 2010
TRANSFER OF TECHNOLOGY
Industrial scale equipment, spread over a very large
area, require a kind of emission deal to be concluded
between supplier and client, making it possible to offset
loud plant components against quiet ones.
Unfortunately, many aspects, in particular the
comparison with different technologies, had to be left
aside due to the limitation to fundamental principles. So, a
grab-type unloader can either be slewing crane or a portal
crane. That has an influence on the kind of noise formation
and propagation, and the actions to be taken in the matter
of sound protection for both types are different as well, as
far as the expenditure on costs and work and their effect
is concerned. The table shown below shall help to make
this clear.
Seen from a theoretical point of view, the unloading
operation could also take place with the aid of continuous
ship unloader. Their advantage is the capability of being
used for loading operations as well. But at places where
this function is not necessary, it would be useful to take
the technology of the continuous ship unloaders into
consideration.
The transport technology allows a selection from
different possibilities, on certain conditions, too. Transports
are also possible by means of wheel loaders and trucks.
But they would only make sense, if the stockyard topology
would be subject to frequent changes. The planner has to
take into account not only the dust- and CO2-emissions,
but also the energy efficiency.
Table 12:
Comparison with the sound power of
different crane types
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