Gregg’s law practice primarily consists of representing businesses involved in unconventional and conventional oil and gas, coal, coalbed methane gas, and other minerals and natural resources, and technologies related to underground mine safety. He devotes significant time to mergers and acquisitions, mineral conveyancing and counseling clients about regulation of oil and gas and coal.

He represents publicly traded and closely held oil and gas producers in connection with mergers and acquisitions, joint development, participation, exploration, operating agreements, drilling agreements, and gathering agreements.

Gregg also represents coal producers and developers in all aspects of coal mergers and acquisitions, coal reserve leasing, acquisition and disposition, contract mining, and mineral conveyancing matters. He represents coal producers and consumers in all aspects of coal supply agreements. He has been active in synthetic fuel and refined coal siting, feedstock and synfuel off-take and facility development and facility operation agreements.

Gregg represents oil and gas and coal producers in matters including facility siting, permitting, design, compliance and reclamation matters. He acts as regulatory counsel to gas producers and coal producers in proceedings before federal and state regulatory agencies involving matters related to license and permit suspension and revocation, ownership and control permit blocking issues, designation of areas unsuitable for mining, and reclamation bond forfeitures. In the past, He also has represented coal producer trade associations on legislative issues before federal and state regulatory and legislative agencies.

Currently, Gregg is the principal McGuireWoods contact with the Marcellus Shale Coalition of which McGuireWoods is a member.

Gregg is a past member of the Pennsylvania Ad Hoc Task Force on Mining Legislation, the group responsible for revising Pennsylvania's surface coal mining laws and regulations to meet the primacy requirements of the Federal Surface Mining Control and Reclamation Act of August 3, 1977; the Pennsylvania Mining Advisory Committee, the group responsible for periodic amendments to Pennsylvania's surface coal mining laws and regulations; and the Pennsylvania Environmental Hearing Board Rules Committee, the group responsible for amending the rules of procedure governing administrative law proceedings before Pennsylvania's environmental trial court.