XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2041
the TS18.60 screen. In Figure 3, under the TS18.60 screen
there were 8 hoppers and boxes on the rails that were pulled
through the screen underflow and overflow simultaneously
to take samples from the industrial-scale process. After the
process was stabilized, samples were taken. The circuit was
operated with different feed rates, feed material size dis-
tributions, aperture sizes and inclinations. (Viilo 1998)
In Figure 4 and Figure 5, 32 tests were done (excluding
strength tests and test number 10) and ten of them were
taken under examination for the evaluation of the passing
probability model.
The comparison process between the passing prob-
ability model results and the 1998s test results was done.
First, the test results data was converted to a form where
the screening efficiency, the throughput rate and the mate-
rial bed depth were calculated from the laboratory test sieve
results of the sample boxes. When the distance between the
boxes was known, it was possible to obtain the screening
efficiency and the throughput rate along the screen deck.
The side distances of the boxes discharge end from the
feed end were 500 mm for box B8, 1500 mm for box B7,
2500 mm for box B6, 3500 mm for box B5, 4500 mm
for box B4 and 5170 mm for box B3. In the selected tests
under examination, only the first screen deck was in use,
due to that, the box B2 was not used. The box B1 was the
oversize material box and from there, the size distribution
for oversize material was determined in the rock laboratory.
After the data from 1998s test results were calculated,
the data from the screened material was entered into the
passing probability model in Excel as the feed size distribu-
tion, the feed rate, the material solid density, the material
bulk density, and the transport speeds in the three different
Figure 2. The test plant layout for the 1998s screen tests (Viilo 1998)
Figure 3. The sample box and hopper arrangement under the TS18.60 screen (Viilo 1998)
the TS18.60 screen. In Figure 3, under the TS18.60 screen
there were 8 hoppers and boxes on the rails that were pulled
through the screen underflow and overflow simultaneously
to take samples from the industrial-scale process. After the
process was stabilized, samples were taken. The circuit was
operated with different feed rates, feed material size dis-
tributions, aperture sizes and inclinations. (Viilo 1998)
In Figure 4 and Figure 5, 32 tests were done (excluding
strength tests and test number 10) and ten of them were
taken under examination for the evaluation of the passing
probability model.
The comparison process between the passing prob-
ability model results and the 1998s test results was done.
First, the test results data was converted to a form where
the screening efficiency, the throughput rate and the mate-
rial bed depth were calculated from the laboratory test sieve
results of the sample boxes. When the distance between the
boxes was known, it was possible to obtain the screening
efficiency and the throughput rate along the screen deck.
The side distances of the boxes discharge end from the
feed end were 500 mm for box B8, 1500 mm for box B7,
2500 mm for box B6, 3500 mm for box B5, 4500 mm
for box B4 and 5170 mm for box B3. In the selected tests
under examination, only the first screen deck was in use,
due to that, the box B2 was not used. The box B1 was the
oversize material box and from there, the size distribution
for oversize material was determined in the rock laboratory.
After the data from 1998s test results were calculated,
the data from the screened material was entered into the
passing probability model in Excel as the feed size distribu-
tion, the feed rate, the material solid density, the material
bulk density, and the transport speeds in the three different
Figure 2. The test plant layout for the 1998s screen tests (Viilo 1998)
Figure 3. The sample box and hopper arrangement under the TS18.60 screen (Viilo 1998)