What is missing is property rights. Mine the ocean floor or the stratrosphere, what matters most is being able to own it. That was the brilliant insight of Hernando de Soto the economist who wrote Why Capitalism Triumphs in the West and Fails Everywhere Else.

Bright ideas that benefit a home, farm, or village burn out for lack of capital to fuel them because the poor have no property rights. That is why they are poor. The consequences are manifold (another mathematical concept). The government's own electrical power utility cannot borrow capital to maintain or expand because the poor steal electricity. It is not the mere tapping of current, but the fact that the users have no legal addresses. Here in America your home will be a good asset for your power company for the next 30 years no matter who lives there because your home address has legal reality. You have a right to the property; when you buy power, you lease that value.

There's a lot of oil under Michigan. When we lived there the last time, I saw a bumper sticker:
EARTH FIRST
We can drill the other planets later.

Dig baby, dig!

Before this discussion goes any further, someone must come up with what property rights inhere in any particular part of the ocean floor, what authority will recognize such rights, and what authority will defend them?

Now for waters that, by international law and convention (i.e., treaties), "belong" to a particular government or governments, the solution becomes obvious. The government at some level must establish a Recorder of Deeds to portions of the ocean floor that lie underneath the "territorial waters" of a particular nation-state.

But what about international waters?

My answer: "The Sea is a Harsh Mistress." In other words, to paraphrase Robert A. Heinlein, the best respecters, protectors, and enforcers of property rights to the floor of the ocean, in waters not belonging to any "landed" government, will be the founders, armies, and navies of independent city-states that people will build on the ocean floor--and on that part of it that they are prepared to defend. The real source of the property rights that "Captain Nemo" (Verne J., Twenty Thousand Leagues Under the Sea) enjoyed, was the armament of his pioneering submarine Nautilus. Likewise, before you can have property rights at sea, you must be prepared to defend a particular patch of water from any actual or potential attackers.

Bearing Sea in Nome Alaska is mined mostly using divers and dredges sucking up the yellow gold. Sections are leased or claims are staked.
Tough and dangerous work.

Me dino thinks that is a great idea. Lib econazis will hate it.
How much sea floor can we actually mine? Think of all the mines on dry ground. I have a stepson who is a coal miner, but I've never seen where he works.
Mines are spaced tiny little dots on a map of any continent. The ocean floor will not disappear should there be mining there.

It will likely play out similar to Offshore drilling rights sold to the highest bidders. But then you will run into this Type of thing just with different names attached.
Obama blocks offshore drilling rights in Arctic, Atlantic
Posted by Bloomberg
Date: December 20, 2016
President Barack Obama banned new offshore oil and gas development in more than 100 million acres of the U.S. Arctic and undersea canyons in the Atlantic Ocean, an announcement certain to provoke a fight with the Republican-led Congress and his successor in the White House.

In a announcement coordinated between two of the world’s biggest oil producers, Canada committed to freeze new offshore leasing in its waters and review the matter every five years.

“These actions, and Canada’s parallel actions, protect a sensitive and unique ecosystem that is unlike any other region on Earth,” Obama said in a written statement. “They reflect the scientific assessment that even with the high safety standards that both our countries have put in place, the risks of an oil spill in this region are significant and our ability to clean up from a spill in the region’s harsh conditions is limited.”

The move — announced a month before Obama leaves the White House — is sure to draw a legal challenge, and there is scant legal precedent on the matter. President-elect Donald Trump may rescind Obama’s order, but the 1953 statute Obama is invoking doesn’t include an explicit provision for reversal and that question could be tied up in court for years.

Although Obama’s decision was cast primarily as safeguarding 31 ecologically precious Atlantic canyons and “fragile Arctic waters,” it was a major victory for environmental activists who have been arguing that even broader climate change concerns should drive the White House to rule out drilling in mostly untouched U.S. waters. Environmentalists said the decision sends a message to the world that the U.S. knows the warming Earth can’t afford to burn “extreme oil” locked under now-protected Arctic and Atlantic waters.

Of course. How else are we going to be able to relive that glorious production called "SeaQuest DSRV"? ;)

Who has the right to sell or lease parcels of the ocean floor is a good question posed by many. Given the many different perspectives posed by many of the world's leaders, it appears that something like this is something wars will be fought over. Considering the progression of mankind and the supposed evolution of our species, we should be able to come up with a solution. What about a global government that has jurisdiction over the globe? The problem is trying to find people who will do the right thing, be impartial, follow natural law. They would not have to be doing it for money other than a reasonable living and would do it to make the world a better place. They would be there not to control or legislate the people, but to protect the people and the environment as well as to guide us into the future. There are more facets to such issues than one could address in a simple forum, but I think a Global Government would be a start.

It's just another frontier, mine it. The environmentalists will always complain, let them eat cake. If it's international waters first come, first served.

privatize and mine away....

Just keep in mind that a lot of what is mined on the ocean floor is manganese nodules, which grow incredibly slowly. Mn precipitates out of the water at a really slow rate, and if we mine them now, they're essentially non-renewable. I have confidence that technology will improve enough to make mining safe for people (and the environment) as well as economical, but there are only so many resources out there.
As everyone has said below, property rights are a huge issue.

There are alternatives, such as this one http://stocksocial.com/petrolithium-n... . The wastewater brought up from oil and gas mining is a concentrated brine, extremely salty and rich in mineral content. While the focus of the article is lithium, I'm certain there are other valuable minerals in the brine, which is referred to as "fossilized" prehistoric ocean water. If this technology becomes widely adopted it kills two birds with one stone: it provides a low cost, low environmental impact way of "mining" scarce minerals; and it solves the problem of wastewater disposal, suspected of triggering earthquakes.

By all means mine the ocean floor and fark the environmentalists. Yes, do the needed homework first but not for their sake but for the sake of the miners.

If it makes sense economically then yes. If not then no.