Good evening,
I already follow all steps added in article. Unfortunately doesn't work for me. I have installed the latest version of GUI from Minergate and now I can only mine with CPU (i5 CPU latest model).
After I try to start to mine ETC, and I use in terminal specific command I obtain 2 message:

1. [OPENCL] No OpenCL platform found
2. No GPU device with sufficient memory was found. Cna't GPU mine. Remove the -G argument
   I must to specified that on my rig I have 4 GPU's NVidia (Gigabyte 1060 6Gb) and 2 GPU's AMD (Gigabyte RX580 8Gb). As operating system I use Ubuntu 16.04.3 on 64 bit.
   Other info which can be useful for you: NVidia X Server Settings appear as "Prime Profiles" Intel (Power Saving mode).
   Regarding to AMD, I cannot install the latest driver (dedicate to mining) because doesn't recognize the command: ./amdgpu-pro-install -y

I hope that you can help me to make it my rig work. Also I am sure that other people receive the same problem. I think missing from somewhere some very important step (only my opinion).

I waiting with higher interest your feedback.
Keep in touch.
Kind regards.