Tack & Hammer: After getting some reports about this cache, I checked on it tonight. They are doing some serious construction work on this area of the park. The wall where the cache was located is still there, but they have re-mortared all the cracks, holes, etc in the wall. The specific cavity in the wall where the cache was hidden is completely sealed over now with new mortar. I'm pretty sure the cache may now be a permanent part of the wall.
Of course, because of everything being sealed up, all the areas to place the cache are gone. Therefore, I am archiving this cache.