size = 10
 
function tablelength(T)
    local count = 0
    for _ in pairs(T) do count = count + 1 end
    return count
  end
  
 
  function refuel()
    print(turtle.getFuelLevel())
    if turtle.getFuelLevel() < 200 then
        found = find("minecraft:coal")
        if found then
            turtle.select(found)
            turtle.refuel(4)
        end
    end
end
 
intebajs = {'minecraft:diamond', 'minecraft:iron_ore', 'minecraft:gold_ore', 'minecraft:emerald', 'minecraft:obsidian', 'minecraft:coal'}

function in_list (tab, val)
    for index, value in ipairs(tab) do
        if value == val then
            return true
        end
    end

    return false
end

function throw_shit()
    for i = 1,16 do
        sname = turtle.getItemDetail(i)
        if sname then
            if not in_list(intebajs,sname.name) then turtle.select(i) turtle.dropDown() end
        end
    end
end

function find(name)
    for i = 1,16 do
        sname = turtle.getItemDetail(i)
        if sname then
            sname = sname.name
            if name == sname then
                return i
            end
        end
    end
    return false
end 
 
function mine()
    turtle.dig()
    turtle.digUp()
    turtle.digDown()
    suc = turtle.forward()
    return suc
end
 
function walk (len)
    x = 0
    while x < len do
        if mine() then x = x + 1 end
    end
end
 
 
 
for i = 0,size do
    walk(size - i)
    refuel()
    turtle.turnRight()
    throw_shit()
    walk(size - i)
    turtle.turnRight()
    throw_shit()
end