Is there an aircraft which could have landed on that 860 metre strip, carried that number of people, and complied with the fuel requirement for diversion?
Yes -
Dash 7 - my last job was with British Antarctic Survey - our regular route was Falkland Islands to our base on the Antarctic Peninsula, 1000 nm with the nearest alternate a further 400nm. If the weather was not suitable at the alternate (i.e. normally....) we could do it PNR (the last hour of the flight was usually committed).
The runway at our base was 900m of gravel (800 or even less would have done....)
The aircraft had long-range tanks (Standard factory option, not a special installation) - we could only carry about 12 people over that range though (in a 50-seater)
(Apologies for thread drift)