Passage: On May 28, 2013, the Alamogordo City Commission granted Fuel Industries, a Canadian entertainment company, six months of access to the landfill to film a documentary called Atari: Game Over about the burial and to excavate the dump site. Xbox Entertainment Studios planned to air this documentary series as an exclusive to the Xbox One and Xbox 360 in 2014 as part of a multi-part documentary series being produced by Lightbox, a US/UK production company. Though the excavation was momentarily stalled due to a complaint by the New Mexico Environmental Protection Division Solid Waste Bureau citing potential hazards, the issues were resolved in early April 2014 to allow the excavation to proceed.Excavation started on April 26, 2014 as an open event to the public. E. T. the Extra-Terrestrial designer Howard Scott Warshaw, Ready Player One author Ernest Cline and film director Zak Penn attended the event as part of a documentary about the burial, as did local residents such as Armando Ortega, a city official who was reportedly one of the original children to raid the dump in 1983. Ortega stated that although he and his friends found dozens of quality games, they gave the E.T. cartridges away because the "game sucked ... you couldn't finish it". James Heller, the former Atari manager in charge of the original burial, was also on hand at the excavation. Heller revealed that he had originally ordered the site to be covered in concrete. Contrary to the urban legend that claims millions of cartridges were buried there, Heller stated that only 728,000 cartridges were buried.Remnants of E.T. and other Atari games were discovered in the early hours of the excavation, as reported by Microsoft's Larry Hyrb. A team of archaeologists was present to examine and document the Atari material unearthed by excavation machinery: Andrew Reinhard (American School of Classical Studies at Athens), Richard Rothaus (Trefoil Cultural and Environmental), Bill Caraher (University of North Dakota), with support from video game historian Raiford...

Question: What material was it to be obscured by, initially?
concrete