The mining using web miner is the less effective way how to mine some PLURA.

I suggest to download some mining software e.g.
https://github.com/fireice-uk/xmr-stak/releases

This way you can try to mine on your CPU or GPU = much better results then mining in your web browser.
Also do not mine solo but pick some mining pool with highest hashrate here https://explorer.pluracoin.org/#pools