What Constitutes Maintenance

My question involves an easement in the state of: KENTUCKY

My grandmother owns several properties with easements from the 1920's to a gas company that read "...so long as such lines and appurtenances thereunto shall be maintained..."

My question is: What constitutes "maintained?"

There has been no gas flowing through those lines for a long time. However, the gas company's successor claims that they have "maintained" the pipelines in lieu of using them.

Thanks for any input!

Unless it's defined differently in the grant of an easement, you would normally use the dictionary definition.