Hello everyone! We're ready to publish our mirror, which has been running since some time ago, though I just added the altarch.
This mirror is hosted in Temuco, Chile, sponsored by University of La Frontera. Details below:

HTTP: http://mirror.ufro.cl/centos/
HTTPS: https://mirror.ufro.cl/centos/
RSYNC: rsync://mirror.ufro.cl/centos/

Sync schedule: Every 4 hrs
Bandwidth: 500 Mbps avg.
Location: Chile
Sponsor: Universidad de La Frontera
Sponsor URL: https://www.ufro.cl/
IPv4 address to authorize: 146.83.205.200
IPv6 address to authorize: IPv6 connectivity not available at the moment.
Email contact: jonathan.gutierrez@ufrontera.cl
Mirroring AltArch: Yes! (http|https|rsync)://mirror.ufro.cl/centos-altarch/

Currently syncing from atlantic.net, and from osuosl.org for the altarch.

I'm currently the mantainer of the mirror, which also has other repos to offer. 
Any issues, just contact me.

Best regards!