Ken,

If you remove the extraneous sieve sizes that are out of the sequence of
progressively smaller aperture as follows it all makes sense.  (check out
the changes I made below)  The % Retained is not cumulative, and you must
add the % retained at a given sieve size and all the % retained at the
larger (smaller number) sieve sizes above it to get the % Cumulative
Retained which when added to the % Passing should equal within decimal
points of 100%.  It is also important to use the correct sieve type whether
International, American, British, French or German.  The U.S. STD/ASTM E11
and the British BS 410 are very similar and easily confused.  You have U.S.
STD/ASTM E11 screens here since the British does not use a 50 mesh screen
but a 52 mesh instead.  I wouldn't split hairs with it though, the figures
are obviously rounded off to the nearest 5%.  And remember... keep your
finger off the scale when you are weighing it!
Happy screening.
Mark Sherman

>Sieve Size      % Passing       % Retained              % Cumulative
Retained
>4                       100                       0
0
>8                       100                       0
0
>16                        90                    10
10        (10+0)
>30                        70                    20
30        (20+10+0)
>50                        40                    30
60        (30+20+10+0)
>100                       15                    25
85        (25+30+20+10+0)
>200                         0                   15
100        (15+25+30+20+10+0)




-----Original Message-----
From: Ken Follett <[log in to unmask]>
To: [log in to unmask]
<[log in to unmask]>
Date: May 25, 1999 8:51 AM
Subject: Sand Sieve Analysis


>Could someone please explain to me where, in the following sand sieve
>analysis that we have in one of our proejct specifications, the difference
in
>passing to retained goes? Should the passing & retained when added together
>equal 100%? If not, why not? I'm faced w/ a dilemma of not being able to
get
>this exact mix from our supplier and needing to understand what is intended
>in order to proceed.
>
>Sieve Size      % Passing       % Retained              Where?
>4                       100                       0
>8                       100                       0
>16                        90                    10
>30                        70                    20
>10
>50                        40                    30
>30
>100                       15                    25
>60
>200                         0                   15
>85
>
>
>Thanks,
>][<en Follett
>