Part of the reason I was able to find the abattoir is because Slyestjester has actually been there. He said it was an hour bus ride from the airport. The elevation change from the airport to the abattoir is about 7,000 feet to nearly 9,000 feet in altitude (2,100 meter to 2,700 meters).
Xining Airport / City is located on the Tibetan Plateau and was/is a hub of the silk road.