Cheep traditional forge idea

Ok im setting up my first forge and i had an idea about how to do it cheep. im going to dig a 6ft X 8ft. hole about mid thigh deep. then im going to wall it in and make a box in the corner with ply wood. im going to back fill the corner back with dirt and pile all the dirt in the same corner to make a mound. leaving a trench for a pipe for air im going to form a space for my forge and pound down the rest of the dirt.

next i would fill the floor with gravel then fill the forging area fire brick and put in my air pipe.
know im like 99.99% shore it will work but i want some input from someone that has set up a forge before. im using a hair dryer for air or maybe a shop vac on reverse.

what do you all say.