Having lived in coal mining country, and visited a coal mine, I'm not. Methane and other gasses that leak during coal mining are carefully monitored and tracked because they're a hazard not only to the safety of the miners, but to the entire operation.
An explosion can kill dozens, destroy the mine, and leave it burning for decades.
But I will state that I'm an outsider in this field, and I suspect you are, too. Perhaps someone with direct knowledge can comment more authoritatively.
It's closely tracked when it's something that could seriously impact the ability of the operation to continue producing revenue.
But what about when it's simply an environmental externality? Some contaminated water supplies can be conveniently swept under the rug, who's going to know and if they do how are they going to prove that you did it? Much better not to keep records on that type of thing and look the other way.
Having a noxious gas sensor in a coal mine is not at all the same as tracking methane emissions from a fracking operation, which can occur over many square miles of the surrounding countryside (the whole point is to fracture underground rocks containing hydrocarbons, which then seep to the surface).
Trump administration is currently getting rid of all rules about methane emissions, so producers will have zero legal requirement in the USA to track, identify, report on, or prevent any methane leaks.
An explosion can kill dozens, destroy the mine, and leave it burning for decades.
But I will state that I'm an outsider in this field, and I suspect you are, too. Perhaps someone with direct knowledge can comment more authoritatively.