Okla. Stat. tit. 69 § 614
When, in the judgment of the board of county commissioners, the expense of working the convicts upon the public highways is too great, on account of the small number thereof, or for any other reason, then it shall have authority to provide all necessary apparatus for working of such convicts upon a rock pile, or rock crusher, for the purpose of providing material for use upon the public highways of the county. Such authority shall be exercised in the same manner as is provided in the preceding section for the working of convicts upon the public highways, and the board of county commissioners shall have full authority as to how and where such materials shall be used; provided, it shall use same for no other purpose than the betterment of the public highways in the county; provided, further, that in any county where the working of convicts upon a rock pile, or rock crusher, is found impractical for any reason, then the board of county commissioners may provide for the working of the convicts upon any public work in which the county has an interest.
Okla. Stat. tit. 69, § 614