function getFuelSlot()
	return 3
end
function getDumpSlot()
	return 4
end

function refuel()
	-- get refuel slot
	local slot = getFuelSlot()

	-- dump all junk
	dump()

	-- refuel one stack
	turtle.select(slot)
	turtle.placeUp()
	turtle.select(16)
	turtle.suckUp()
	turtle.refuel()
	turtle.select(slot)
	turtle.digUp()

	-- dump leftover fuel
	dump()
end

function dump()
	-- get dump slot
	local slot = getDumpSlot()

	-- empty all slots after dump slot into chest
	turtle.select(slot)
	turtle.placeUp()
	for i=slot+1,16 do
		turtle.select(i)
		turtle.dropUp()
	end

	-- put chest back in dump slot
	turtle.select(slot)
	turtle.digUp()
end