About 21 cubic feet
0.148 cubic yard for every 3-inches deep
2800 feet of gravel
18 cubic feet 3 inches is 1/4 foot, so the volume is L x W x D = 8 x 9 x .25 = 18 cubic ft.
It needs: 8*4*2 = 64 cubic feet
None. You have only given an area and no depth. Without a depth, the volume is zero and thus the hole does not exist and no gravel will be needed. If you meant a round hole 12 ft by 14 ft it is still unclear as to the dimension of the hole: firstly which is the depth (the 14 ft is the most likely), but when speaking of a round hole would you mean the perimeter, the radius or diameter for the given measurement? They all lead to different volumes and hence difference amounts of gravel needed to fill the hole. Ans 3 - 12 x 14 is NOT round it is rectangular
112 cuft
17.5 cubic feet or about 3/4 of 1 cubic yard.
About 21 cubic feet
10-1/2 cubic yards
0.148 cubic yard for every 3-inches deep
There is a fill plug on the right side. Fill to the bottom of the hole
2800 feet of gravel
18 cubic feet 3 inches is 1/4 foot, so the volume is L x W x D = 8 x 9 x .25 = 18 cubic ft.
It needs: 8*4*2 = 64 cubic feet
If you are referring to a 4 cycle small equipment engine then use SAE 10w30. Pour in just enough to fill it to the full mark on the dipstick. If you have no dipstick then fill it up until it reaches the top of the fill hole.
There is NO dirt, it is a hole! If you want to fill it with dirt, that is 4x6x12=288 cubic feet, weighing about 28,800 pounds