The nether star hammer mines a 3x3 tunnel 16 blocks deep. MinersAdvantage allows when holding the tilde key to mine a specific number of blocks, I have it set to 3x3x3 a 27 block tunnel. When using both mods and holding the tilde key the game crashes. Sometimes the crash is intermittent, so I'm guessing that this could be related to MinersAdvantage veination feature to mine connected ore veins. This is just a guess. The crash is very repeatable. I am using the latest mod release for both mods.

MinersAdvantage-1.12.2-1.3.18.223.jar
sparkshammers-1.12.2-1.9.2.jar

MOD CONFIG FILES
config.cfg.txt
minersadvantage.cfg.txt

CRASH
crash-2018-08-25_18.19.10-server.txt

PS, NOTE: Another tool that does multi-block mining which does not crash. Cyclic adds a pickaxe called "mattock" that mines multiple blocks. When combined with MinersAdvantage it does not crash when holding the tilde key. It has an odd effect, but basically it combines the mining rules of both. For example if I have set MinersAdvantage to mine a 3x3x3, mattoc is statically set to mine a 3x3x1, the end results is that for every block in the 3x3x3 that MinersAdvantage tries to mine, at each block a 3x3x1 get mined.

Even without holding the tilde key with both mods enabled, the netherstar hammer crashed, again, guessing its a conflict between the minersadvantage veination logic that mines ores outside the scope when using the netherstar hammer.