(Adds context, details on private placement) Sept 10 (Reuters) - The Metals Co (TMC) was trading down around 17% after listing on the Nasdaq on Friday following its creation from the merger of deep-sea mining exploration firm DeepGreen and a blank-check company. TMC opened at $11.0535 a share but started falling soon after, hitting a low of $8.31. In a filing on Tuesday, TMC said it had received only $110.3 million of the proceeds from a private placement of Sustainable Opportunities Acquisition Corp (SOAC) shares, having entered into agreements with investors for a $330 million placement. “SOAC intends to continue to seek to enforce the funding obligations of the non-performing investors under the subscription agreements, but there can be no assurances that it will be successful in those efforts,” it said. The Metals Co has exploration licenses for parts of the Pacific Ocean seabed, where it - along with other deep-sea mining prospectors - hopes to mine potato-sized rocks rich in cobalt, nickel, and other battery metals. The fledgling deep-sea mining industry has come under fire from environmentalists who call for a moratorium on the practice, saying too little is known about the harm it may cause to deep-sea ecosystems. The Metals Co has argued that mining the seabed will be less harmful to the environment overall than mining on land. (Reporting by Helen Reid; Editing by Edmund Blair and Susan Fenton) Our Standards: The Thomson Reuters Trust Principles.