Comment by matznerd | Hacker News Reader

Comment by matznerd | Hacker News Reader

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Hi, co-founder of Project Vesta here. Based on a CO2 life cycle assessment, to minimize CO2 created during transport, the idea is to utilize mines within 300 km (186 mi) of the destination beach. Including mining, milling, and transport, we can hopefully maintain only a 4% efficiency loss in terms of CO2.[1]

This paper has a few examples of models where it is 93% efficient for mines within 1,000 km. [2]

Fortunately, there are olivine reserves found all over the planet in a formation called dunite (contains 90% forsterite olivine).

Further, for many of the first beaches, we will be looking to use tailings piles (waste rock) from previously dug and developed mines, as well as the infrastructure from those mines, such as rail for transport. Since olivine is found in volcanic rock formations close to the surface, in the process of mining other minerals that are found in volcanic formations such as diamonds, many tons of olivine rock have already been dug up and deposited in large piles on the surface. By utilizing this rock we would not produce any additional CO2 from mining, and only from crushing/transport.

We are definitely taking the CO2 penalty into account in our calculations and strategy for deployment.

[1] https://projectvesta.org/science/#dflip-df_978/1/ [2] https://projectvesta.org/science/#dflip-df_93/2/

Will olivine-covered beaches be still good for recreation? Will olivine sand produce fine dust that would muddy the water?

I bet the first few green beaches would just look cool enough to increase he stream of tourists — as long as walking over an olivine beach feels safe and not unpleasant.

Also, is dumping olivine on rocky but flat enough shores an option? That is, may it not replace existing sandy beaches but form new olivine-only beaches?

Green Sands Beach on the island of Hawai'i is a big tourist attraction. So, yeah, it seems fine for recreation. (Except it won't be cool anymore if every tropical beach is green...)

They mention that only 5% of tropical beeches would need to become green.

Hi, yes the beaches would still be good for recreation and there should not be a noticeable muddying of the water. The existing beaches of olivine (such as Papakolea Beach in Hawaii that is pictured on our website) are safe and have no observed negative effects on wildlife or humans.

If you look at the tabletop shaker experiments on the website, the water is cloudy because it is not being refreshed. In an open-system such as on a beach with water constantly refreshing, that would not be an issue.

The olivine can be placed on any shoreline or coastal area. The "tropical shelf-sea beach" set up we constantly refer to is simply the optimal and preferential solution. The main effects we are utilizing the beach for are that (1) the tumbling motion of the waves causes a constant abrasion that breaks up a silica coating that rapidly forms on exposed olivine and (2) the collision of grains on the shoreline causes smaller slivers to chip off, that themselves rapidly weather.

We want shelf-seas because the grains will be pulled off the beach and will continue to be weathered through underwater shear stress forces on the sea bed. Other locations work as well, but the olivine may take longer to weather if there is less motion, colder water, etc.

Would the olivine actually need to be (rough) sand or would pebbles or, say, fist-sized rocks work almost as well?

How the beach feels mostly depends on the particle size; magnetite sand, quartz sand, and obsidian sand feel about the same. (At some extreme, that would presumably break down; I wouldn't want to walk on a beach made of shredded fiberglass, at least until it had gone through some physical weathering. And sawdust does feel different. But olivine is not such an extreme case.)

Hi Eric,

How do you plan to compensate countries who own the beaches or waters targeted by the project? Do you have an estimate of how receptive a community will be to having their beach turned green, especially if they rely on it for a portion of their income?

A country outside of the world's economic powers might want financial insurance in the event that the the project causes ecological damage and hurts their economy.

Several California cities are already spending millions annually to dump sand and rocks and to build/expand seawalls, to try to stave off the ocean taking prime beachfront real estate (and it's not working, in the long run).

Those cities (though not in the ideal location for this project, I guess) would likely be ecstatic to have subsidized assistance (though who subsidizes it?). They're losing the beaches no matter what they do, the question is how long will it take, what will it cost to push it out a few more years, etc. For cities that don't have the budget to dump millions of dollars worth of sand only to have it mostly wash away in the next storm, a green beach is probably much more appealing than no beach.

My main point was about developing countries. Eric himself noted that "the idea is to utilize mines within 300 km (186 mi) of the destination beach" and "or many of the first beaches, we will be looking to use tailings piles (waste rock) from previously dug and developed mines, as well as the infrastructure from those mines, such as rail for transport". The idea is summarized in this image [1], which shows mines and their associates beaches that the project intends to target due the proximity.

Most of those beaches are in developing countries. If nourishing the beaches with olivine has some unforeseen, negative ecological consequence, those countries might not be financially equipped to deal with the cleanup. How are those beaches going to be insured?

In the case of California, I'm not familiar with their beach nourishing process, but I assume they are using sand that is more similar in content to what was naturally present. If the beaches have been replenished for years, then we at least have some idea about the short-term effects.

1. https://projectvesta.org/wp-content/uploads/2019/04/Image-59...

Shouldn't the thing pay for itself in climate impact costs avoided?

The benefits are global though, while the impacts on beaches are local.

Which is true of all of the costs of climate change. The costs are already being most harshly felt in poorer communities and nations, and that divide will accelerate the more expensive and resource-intensive it becomes to keep living "normally" under climate change. As droughts strike rich regions, they'll build dams to retain water than would have traveled to poorer regions (e.g. as a significant portion of Californians want to do already at even the first hint of climate change striking the area, despite its impact on people to the south).

I don't know what the right answer is on this question, but I know that the pain of climate change will be felt by poor nations more than it will be felt by rich ones, no matter what. It may be that staving off climate change, even if it has its own negatives, is less bad than the alternative of doing nothing for those places and communities. But, maybe not. Hopefully it would get a lot of study and small scale experimentation before going big.

please address the release of nickel into the environment. That stuff can be trouble, especially for people with sensitivities.

He did so here: https://news.ycombinator.com/item?id=20404766

Darn it! I thought I searched for a response first. Thank much!

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