<Item href="/Effects/_(ParticleInstance)/Buildings/Mines/OreMine_sparks.xdb#xpointer(/ParticleInstance)"/>
I removed the reference to them in the effect. And the glow disappeared.
To be more precise, in the sparks themselves the orange glow could have been removed by deleting Glow05. But a strange bug occurred where some piece of texture flickered at a certain angle... so I went with this approach — removed the sparks. Of course, this also got rid of the tiny shimmering of gray dots, but it's better than what was there before.

Below I'll post an example (removed the glow, but at a certain angle this thing on the right flickers)