off the fine fractions on each of those grindings.
We do the sieving
because the fine fraction tends to cushion the oversize material that we
are trying to abrade.
We had an interesting occurrence in that every time we pried up the
lid of the can there was a puff of what looked like smoke.
kinds of extremes
awhile.
to
avoid that.
We cleaned
We went to all
up rather frequently for
We finally avoided that and a related problem ended by simply
puncturing the bottom of the can, that vents the air that's been heated up
by the ball-milling process, and we continue by cutting out the entire bot10
tom of the can (REECo 81).
11
the can and it also makes the transfer of the material out of the can a lot
12
easier because you are pouring it across a smooth surface instead of across
13
a rim.
That does away with stone lodging in the rim of
14
The steel balls are retrieved after the grinding session (REECo 82),
15
and we now come to the part which jis an absolute art, and that is, turning
16
the can upside down,
17
spilling it or dropping the whole thing.
18
Eddie Eubank have developed this talent to a high degree.
onto the sieve
(REECo 83), without making dust or
Richard Grisham in the back and
19
For those of you who have not seen a soil sieve (REECo 84), the set
20
consists of a metal pan. in which the "less-than" fraction is collected, the
21
brass screen, which does the separating, and the metal cover which keeps us
22
from contaminating the rest of the laboratory.
23
together as shown in the previous slide, and the separating is done on the
24
vibratory shaker (REECo 85).
25
separation is a function of the characteristics of the soil that is on the
26
screen.
27
20 or you'll sieve for six. hours at a setting of 75.
28
much more successful if you listen to the vibrator and the screen will tell
The three parts are taped
This, also, is an art.
The time to reach
You cannot say that you will sieve for ten minutes at a setting of
144
It has been found