Changed mine.lua with configurable fuel store amount

mine.lua

@@ -2,11 +2,19 @@
 -- current position and facing
 
 -- +x = right of start, +y = forward of start, +z = up of start
+local FUEL_RESERVE = 800
+
 local FORWARD, RIGHT, BACK, LEFT = 0, 1, 2, 3
 local mode = { x = 0, y = 0, z = 0, facing = FORWARD }
 mode.mine = { forward = true }
 local block = {}
 
+function refuelUntil (amt)
+    while turtle.getFuelLevel() < amt do
+        if not turtle.refuel(8) then break end
+    end
+end
+
 function mineSides ()
     if mode.mine.up then
         turtle.digUp()
@@ -126,7 +134,7 @@ end
 function moveAndCheck (x, y, z)
     move(x, y, z)
     if inventoryFull() then dropOffItems(true) end
-    if turtle.getFuelLevel() < 100 then turtle.refuel(8) end
+    refuelUntil(FUEL_RESERVE)
 end
 
 function generateNextSteps (w, l)
@@ -188,7 +196,7 @@ end
 
 function mine (block)
     -- fuel and go to starting corner
-    if turtle.getFuelLevel() < 100 then turtle.refuel(8) end
+    refuelUntil(FUEL_RESERVE)
     mode.mine = { forward = true }
     moveAbs(block.x, block.y, block.z)
     local z_dir