I've made a dangerous assumption in this case that all coins are of different mintmarks.
By the way, here are the thickness of them:

The third coin is a massive 11.6 grams opposed to coin next to it, which is just a mere 8.6grams. The technical weight is supposed to be at 10.24 grams but we know it's rarely close to there. It's usually weighted in kilograms or something.
The weights of the 7 coins that I'm going to present are as follows: (Of course, corrosion does have an impact on how heavy these coins should weight originally)
1: 9.5g
2: 9.7g
3: 11.6g
4: 8.2g
5: 10.2g
6: 10.0g
7: 10.6g
Nevertheless, here is for 1840. Special attention is paid upon the font characters of 1 копейка серебром
I've uploaded larger photos here: http://www.gxseries.com/numis/rus_imperial/1840_2/
Coin 1: SPM?

Coin 2: EM?

Coin 3: CM?
Out out the first three, it's easy to assume that coin 2 and 3 are of EM and CM origin as they only have two characters. I have trouble designating which one should go to which but it's interesting to note that in this particular year, the letter "O" overlap the letter "M"
The only reason why I judged the third coin as a coin from CM is due to it's crudeness as well as I suspect CM mint has a less severe weight control program. I find this year difficult to judge. Maybe someone has a better idea than I do.
Part 2 continues in the next post...



