the Dam(n) Valve

The saga goes on.....
As you recall, last Fall after playing with the upstream (underwater) main valve for too long, it was decided, by the valve company's representative, to remove the valve to inspect and reset it.
This sluice gate valve was leaking approximately 60 gallons per minute (GPM). Industry standards for a valve of this type and size is closer to one GPM.
The valve was removed and moved to the Borough building. A representative of the valve manufacturer (Rodney Hunt) subsequently inspected the valve and reset all adjustments.
It was 'suggested', by the valve manufacturer, that the problem was the flatness of the mounting flange on the dam headwall, 50' below normal lake level. This mounting flange is part of a thimble shaped piece that is bolted and grouted to the headwall. While removal of the thimble is not impossible, it is a major project, one best done above water. The suggested solution was to make a machined flange, flat to 0.010 inches, and bolt this between the valve and thimble. These are 30” diameter flanges.
We were unable to coordinate schedules to reinstall the valve prior to Winter setting in. The first attempt to install the machined flange, with an underwater setting epoxy, to the thimble, failed in May. The epoxy was to take up the imperfections in the thimble leaving the other surface of the machined flange to mate with the valve. The second suggestion was to use the machine flange in a sandwich with a thin gasket, supplied by the valve manufacturer, between the flange and the valve. A thin rubber gasket to be used between the flange and the thimble. All bolts then torqued to the same tightness with the rubber gasket doing what the epoxy was suppose to.
Finally on Thursday June 16th the dive company (Marion Hill), assisted by our engineering firm CME, Borough personnel, and the marina, put the valve into the water, transported it to the dam and reinstalled it under 50' of water utilizing the second method. The valve manufacturer was not present, their representative, who actually sold the valve, Learco, was on site.
Friday, June 17th, the divers torqued the bolts holding the valve in place and started testing. Initially when the downstream valve was opened and the pipe drained the leakage was about ½ GPM. The gate was raised a few inches and lowered, the leakage upped to about 2 GPM. The gate was fully cycled several times and when closed was leaking approximately 28-30 GPM. Neither the valve manufacturer nor their representative were on site. As it was the end of the day and the valve manufacturer was not there to give advise, work was stopped and the divers left.
After several days the flow had dropped to 12 GPM.
There are discussions ongoing between all parties involved. Some of the questions being explored are:
-does Learco or Rodney Hunt have any further suggestions?
-should the down force closing the valve be increased to be sure the valve is properly seated?
-further adjusting the valve wedges?
-see if closing the upstream valve without flow going through it would allow it to seat tighter?
-approach the DEP with what we have?
To be continued.............