I happened upon this bug (well, exploit) by accident while trying to move the diamond chest of ores I mined using my digital miner.

The digital miner mined 2 rock crystals, which were in the chest. When I tried to put a Mekanism cardboard box on the chest, so I could move the chest with it's contents, 2 rock crystals popped out of the cardboarded chest. When I removed the cardboard box, there were still 2 rock crystals. So now I have 4 rock crystals.

I tried placing the 4 rock crystals in a vanilla chest, put on a cardboard box, and now 4 rock crystals popped out. I remove the cardboard box, and the 4 rock crystals were still within the chest, so I now have 8 rock crystals.

I'm on version 0.5.4 of the pack, with no changes to the modpack.