The desert landscape of the al-Kayara district, located to the south of Mosul, is dotted with dozens of harraqas – large cisterns with several pipes attached to each, which the locals used as improvised furnaces to refine crude oil and produce straight-run gasoline.
"The first such furnace was bought in Syria and installed in the village of Azba. People from other areas learned about it and started making similar contraptions. Any blacksmith can make a furnace like this. And the terrorists also started commissioning harraqas," Mustafa said.
He added that the furnaces cost no more than $800 each, and that they were either brought here from Syria or made by local craftsmen.
To get the harraqa to make fuel: first crude oil is poured in and gets heated for 24 hours; when the process is complete, about 220 liters of high-quality gasoline is pumped out of the furnace via a special pipe; the remaining substance is heated further, allowing the furnace’s operators to extract low-quality gasoline and diesel fuel; and the remaining viscous liquid was used as incendiary compound.
According to Mustafa, the terrorists sold crude oil to for processing via the harraqas for $20-30 per barrel, allowing the latter to earn up to $200 for each barrel purchased.
Essentially, each harraqa furnace earned Daesh about $30,000 per month, Mustafa explained.
By the time the oil fields were liberated from Daesh control, most of harraqas were rendered inoperable due to extremely active use, and the locals repurposed them for other domestic needs, he added.
