It's called Frack Focus, but you have to know which well it is, and the time of the frack. It usually is not reported until 2 months after the well comes out of confidential status, way after the fact. You track the wells by permit date, and the North Dakota Industrial commission provides a website that provides most of the info as to what well, & permits are actively being drilled. It takes a great deal of skill & data mining talent to get the data for which you are looking, but it is possible. Otherwise we are truly treated like mushrooms, kept in the dark & fed BS...
Don't expect the local papers to cover it, the local are kept ignorant of any negative Oil company activity until it's really obvious to the owners. The containment pond, is a earth built, plastic lined berm pond, in which the store the frac fluid. That probably breached, due to poor contraction, if that is the issue here.
Check out the Frack focus site, and look at previous Frack fluid reports by that company to get the formulas. There's more sand & ceramic micro beads in the frack fluid than salt.
On the other hand, the real problem is the need to dispose of the well water products from the Oil pumping, as that is the main source of salt water. There's usually equal parts of Oil, salt water & Natural gas liquids recovered from a frakked well, and that may be the source of the "Brine". This is usually re-inserted back into the earth via a deep disposal well, which casings are supposed to be heavily regulated. These wells may be Old frakked wells, that have ended production. If that breached, or leaked, you could get a fairly bad contamination & land spoilage event, and that has happened before, many times.