Making leaf mold

I stored leaves in a bin for 2-3 years, thinking it would turn into leaf mold.
I have crumbly leaves, but no leaf mold.
I am wondering what can I do to the piles to turn them in to leaf mold?
The bins are 3 feet high, and 2 feet in diameter. I don't have room to make one bigger bin. The leaves were not mown before storing, I don't have that option. (I am in zone 6b)

thanks..

sprinkling some high-nitrogen material on the heap as it is fabricated is one more method for speeding the change of crude leaves into leaf shape. High-nitrogen materials I've once in a while utilized incorporate soybean feast and grass clippings,