They are usually buried six to eight feet deep and unless you were there during construction, the only indication you have of their existence is the occasional surface marker or casing vents at road crossings. A clear-cut strip through a wooded area may be another indication.
The two markers on the right in this image are casing vents. Third from right is a marker for aerial patrols. The other four provide a general location of the pipeline and usually include warnings to “Call before you dig.”
The advocates are always looking for new ways to divert your attention from the two greatest threats to our wild horses: Themselves and the public-lands ranchers.