News: Tailings dam concern may kill Iluka takeover of Sierra Rutile, page-12

I did read your comment, and found it misleading.
But perhaps I should choose my wording more carefully.

Seeing comments like
"by their very nature, tailings dams are designed to trap and contain toxic byproducts of mining activities"
Makes me see red a bit

But I'm not going to get into mudslinging

By definition clays and silica are not salts.

I agree gold, copper and base metals can mobilise heavy metals, etc. But there are lots of miens that either do not chemically modify and mobilise toxic species, or simply don't have them present.
My comment that "most mining does not release heavy metals" is more based on experience than stats. I'm not saying some mining does not. So for full disclosure I could be wrong. But its simplistic and (I believe) misleading to just say that this is mostly the case. for example, graphite, silica, limestone, dolomite, silica, even iron ore (and the list could go on). Activities do not results in the release of heavy metals.

Tailings dams are just used to hold waste material, you can't just dump slop back into the mine. In some instances tails facilities are eventually retuned to the pit.. but not always