Outside of Trove & DIGS, which you're already using, I'm not sure Dron.
My family held Gold Leases around Hill End & Windeyer during the first gold rush period then early 1900's but apart from some gazette notices on Trove when various leases were granted (or in some cases not) I can't find much other info. I did find a hand drawn map on DIGS showing the rough location of some of the GL's but nothing yet on yields etc. The best I could find on their yields was things like "a good amount of gold bearing material was brought to grass today" or "a large parcel of gold was taken to Mudgee for sale" etc.
On DIGS some of the various mines that did report are captured on reports on the whole area. You may have to search under the whole goldfield then wade through the reports - time consuming I know but it may lead you to what you're after.
Keep in mind that some mines/miners didn't report a lot, if any, of the "required" information. There is many a goldfield where the exact gold yield will never be known due to the lack of reporting. Would have been hard to keep a fairly wild bunch of nomadic gold seekers in line at the best of times let alone get them to submit their paperwork.
Good luck with it & if I find another way I'll let you know (& vice-versa please :Y: )