On Shabbos: Shaking basket with fruits and rock, why not borer (selecting)?

Question

It says in SA OC Siman 309 Sif 3 that on Shabbos if one wants to carry a basket that has in it fruits for the purpose of the fruits themselves if there is a rock inside of the basket as well one must shake out the rock from the basket (in order that it shouldn't be a problem carrying a muktzeh item together with the fruit.) This is however only in a case where the fruits will not be damaged in the process (if they will be one doesn't have to shake out the rock.)

Why is this not a problem of borer (selecting) when one shakes the basket with the intention and purpose of removing only the rock from the basket that is mixed together with the fruits? It could be however that the wording of the poskim (Shulchan Aruch itself as well as the SA HaRav in Siman 309 Sif 5 and M"B in Siman 309 Sif-Katan 11) that one is shaking out the fruit together with the rock would show that there is no problem of borer in such a case (and that the intention was in telling the person to remove the rock was to do so together with the fruit.) However from M"B Sif-Katan 10 we see that if there is a possibility to take out the rock itself then that should be done. So my question again is removing the rock from the basket by way of shaking it, why is this not considered to be a problem of borer?

Answer 1

I found in a Sefer "Toras HaShabbos Chelek Alef" (a modern day kitzur Sefer that he addresses this point. See Perek 15 on Hilchos Borer Footnote 102 (towards the end.)

He writes that seemingly it should be ossur to remove the rock so why does the SA allow this. He says that could be the reason is is because the person is not m'cavain (doesn't have the intention) to be "m'sacain" ("fix") the mixture of friends for the purpose of eating it, rather his intention is to eliminate the any problems of muktzeh in order to carry the basket with the fruits. However if his intention would have be to remove the rock in such a way in order to make the fruits now "fitting" to eat then this would be ossur.

This reasoning I have heard as well in the name of poskim. However I believe this still needs investigation.

(He makes an additional (interesting) point in the Sefer Toras HaSahbbas that if this is considered to be "borer m'doraisa" or perhaps ossur only m'drabbanan. See there. His reasoning being that this is considered "borer c'lachar yad" (selecting in the not normal way.)

Answer 2

In order for for Borer to be an issue one must have a teruvos, a mixture (see Shemiras Shabbos K'Hilchasa 3:3). Unfortunately this can be difficult to define precisely, but it would seem obvious that the situation as described must be one where it isn't applicable. I think this can be illustrated by imagining the situation. If you were to picture a bowl of Apples and Oranges mixed together, you have a mixture. A stone on the bottom of a basket, is a stone in a bottom of a basket. Perhaps even in a situation where the stone is "in" the apples it could be small enough that it would/could settle to the bottom on its own, which would also exclude it from the category of a mixture (see Shemiras Shabbos K'Hilchasa 3:6).