How do you know that? The article doesn't say anything about it and you don't provide any proof either.
Well for starters I've worked in the industry for a few decades, I've been a lead engineer on several major pipelines have a decent understanding that all pipelines in the US are buried unless there is an extreme reason not to bury them.
Secondly, this isn't the only discussion about this pipeline. A little searching can provide some direct information.
http://mountainvalleypipeline.info/
The pipeline, a joint venture of EQT Corp. and NextEra Energy, would transport natural gas at high pressure from West Virginia through a buried, 42-inch-diameter steel pipe.
I've been involved in preliminary planning and permitting of US pipeline, mostly Natural Gas like this one. This one isn't unique and different.