I believe he was among those re-interned in a Chattanooga cemetery.

.....

This piece indicates he was buried in Tennessee, but not exactly where.

Confederate States Of America Veterans Buried in Beauregard and
Vernon Parishes, Louisiana

Cooley, Wesley Allen Oct 4 1838 Sep 20 1863 Wales Cem (monument)

Pvt 16th La Inf Co E Killed at Chickamauga, buried in Tenn

Wesley Allen Cooley ~ Private Company E, 16th Louisiana Infantry.

http://files.usgwarchives.net/la/beauregard/military/veteran.txt

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Pioneers - Soldiers detailed to carry out duties similar to those of mdern combat engineers such as cutting roads, repairing bridges and works, and dismantling enemy artillery, fortifications, and railroads;