A OPEN PIT MINING AÇIK OCAK MADENCİLİĞİ

23 rd
During our investigation we have
planned the flights of different sectors
according to their geolithological,
geomorphological and vegetation coverage
characteristics.
For each sector have been defined the
single different consistent resolutions needed
for the elaboration of the DEM of the fronts,
the quarry lay, the landfills, the derbies
accumulations and for the over-flow
furrows. This area of interest (AOI)
investigated includes a front of about 215 m
long with an average height of 15m, which
defines a quarry area of about 9.361 square
meters. The quarry lay morphologically
consists of several levels resulting in both
phases of mineral extraction and different
sizes sterile materials accumulation. Inside
this quarry there are different degradation
processes like collapses from vertical walls,
diffuse runoff, accelerated and differential
erosion.
These problems are particularly acute in
the northern portion of the quarry lay, where
the action of the water has given rise to deep
furrows, gradually conveying the surficial
runoff materials to the Rio S'Alluminu.
The photogrammetric survey of this area
has been developed in three steps. The first
step is the camera calibration performed in
bundle adjustment, with the set of fixed focal
length lenses to be used, and correcting.
The second step is the planning of the
very first flight, used for the construction of
an orthophoto of the AOI. The orthophoto
was generated using as a basis a network of
GPS points, geo-tagged with the UAV-GPS
flight log (latitude, longitude and elevation).
This flight was performed at the altitude of
80m usith fixed focal length of 20mm, in
order to garantee a fast coverage of the area.
The orthophoto was finally imported in
the dedicated software “MikroKopterTool”
(by Mikrokopter) as a base to accurately
planning (in terms of flight altitudes and a
safe distance from the walls the next
photogrammetric flight).
The different altitudes of the acquisition
flights (from 5 to 50m) have been
established taking into account the ground
sample distance (GSD) needed (0.02 to 0.06
m/pix) in relation to the fixes focal lenses of
35 and 50mm used.
After the definition of these parameters
the flyght was planned by waypoints,
according to the photogrammetry rules:
longitudinal overlap >70% and cross-overlap
>=50% (Fig. 3).
The flight planning is a very important
phase, especially when the surfaces that have
to be reproduced, as in our case, show
different material characteristics, strong
steepness and different exposition to the
incident light.
The flights were performed at various
distances from the surface, taking always
convergent photos. Any combination of
photographs, whether in stereo pairs, stereo
triples, strips, sub-blocks or blocks, is
handled by forming the set of observation. In
addition, the UAV platform used allowed to
replace the traditional photo capture from
the ground, performing some very lowaltitude
flights (5m) with GPS flight log. The
total number of photos captured is 284.
The third step of our work has been the
use of the Topcon RTK-GPS receiver for
collecting GCPs field data points with an
accuracy of RMSE measurements