MoneroMilk is a XMR mining pool. It has a 1.2% fee (of which 0.2% is donated to the Monero core dev team) and runs on a Prop distribution method. The payout is set at 0.35 XMR.
Obelisk is a wholly-owned subsidiary of Nebulous, Inc., the company behind the creation of Sia, a blockchain-based storage network that operates on top of a decentralized market.
The Obelisk company focuses on building mining equipment for the SiaCoin, a Blake2b-based cryptocurrency. So far, the company has released one ASIC miners dubbed Obelisk SC1.
HydroMiner is a cryptocurrency mining company using green energy drawn from hydro power stations in the Alpine region of Europe. Hydro-power is generally thought to be one of the most effective and lowest-cost renewable energy resources. It is environmentally friendly, carbon-neutral and natural.
Iron Vault offers a variety of straightforward turnkey solutions for individuals to partake in their own crypto-currency mining operations. Their products and services allow all types of individuals to safely operate their own mining hardware in one of their dedicated state-of-the-art data centers.