The first oil wells were dug by hand. Using drilling techniques for oil and gas began in the mid-nineteenth century. Hydraulic fracturing (fracking) uses novel drilling and pressurised extraction techniques using sand and toxic mix of chemicals to draw gas and oil from deep rock formations. In long-settled Pennsylvania and population-sparse North Dakota, only some of the farmers own the mining rights to their land, producing economic winners and aggrieved losers. In Pennsylvania, with its long-established mixed farming, fracking occurs side by side with milk production. Signs at fracking sites show how much water they are allowed to use - usually up to five million gallons, drawn from local rivers, with other trucks removing poisonous liquid waste for processing and burial. In North Dakota,  unwanted gas at the oil fracking pads is released into the air, with signs warning walkers of its poisonous effects. The touristic Custer Trail, at the southern boundary to the Theodore Roosevelt National Park, contains many such pads.  Pennsylvania contains a small, vociferous minority who oppose fracking and which the industry keeps under active observation. 

There is no such outspoken opposition in North Dakota. The oil industry provides taxes and jobs and its influence permeates state politics. Speak privately to many original residents and they complain that the oil boom has brought with it higher living costs but little or no economic improvement. Conventional photographs of oil fracking pads (or more correctly, hydraulic fracturing pads) look almost entirely innocuous at first sight. Perhaps this is because their workings are invisible. One doesn’t see what is occurring beneath them or what is released above, except if one is actually present or when gas releases are set on fire. Gas fracking pads produce no visible releases at all, although a network of ground-based gas transportation pipes, barely visibly except from the air, extend over a distance to the gas compression sites.  Glover’s picture began as digital colour photographs which were then digitally inverted, simulating a negative black and white image. The attempt is to denormalise the taken-for-grantedness of a scene in which everything is open for inspection but nothing can be seen.