As a donor on Mineverse on op prison you get some good stuff....But in the extra section of buycraft maybe you can add a custom plot mine. With the custom plot mine you can turn your plot into a mine of the blocks of your choice. Heres the thing.....You cant have all diamonds or all emerald. It has to be a mixture of some low cost blocks and some high cost blocks.

 

Although it seems like a good idea, the mine and plot areas probably run off of different plug-ins. I wouldn't know but that's how it seems. Each person who would want to do this would probably have to have their plot coordinates added to the plug-in so it could be reset when all other mines (A-Z) are. Plus item durability acts differently on plots compared to at the mines for certain tools.

It's a neat idea and I would like to support, but I think it's highly unlikely to ever happen.

 

I dont know what plugin they use but with some prison plugins you just have to select a world edit area then type in the blocks you want to put in. Then it does most of the rest automatically