SemGroup Corp./NGL Energy Partners LP joint venture Glass Mountain Pipeline LLC will add a 44-mile extension to deliver crude oil from north-central Oklahoma's STACK resource play to Cushing, Okla.

The 215-mile system already delivers crude oil from the Mississippi Lime and Granite Wash plays to Cushing, Okla. Route selection is complete, and right-of-way acquisition is ongoing. The extension is set to be in service in the last three months of 2017, according to a Dec. 19 news release.

Glass Mountain also entered a long-term, fee-based transportation agreement including a committed area of dedication with a major investment-grade producer in the STACK.

Glass Mountain is owned 50/50 by SemGroup and NGL Energy Partners.