Most geoengineering schemes proposed to combat Greenhouse Warming by artificially cooling the planet are really just scaled up versions of natural processes. For instance, plants use CO2 to grow so one geoengineering idea is to encourage the planting of tree farms to pump down CO2. Clouds block sunlight, so perhaps creating artificial clouds would be beneficial. Volcanoes cool the planet, so artificially putting volcano-like aerosols into the upper atmosphere could replicate and expand upon this effect, and so on.
The chemical weathering of rocks also involves processes that take CO2 from the atmosphere. So of course there are geoengineering schemes based upon artificially enhancing the natural weathering of rocks. At first glance this seems like a great idea, but there is one serious flaw intrinsic to this particular geoengineering plan. Rocks must undergo a process known as "physical" or "mechanical" weathering before they are chemically weathered and interact with CO2. The mechanical weathering processes produces cracks and fracture and breaks the rock apart. Without mechanical weathering only the outermost skin of rocks will be subject to chemical weathering, as water and air will only be able to come into contact with the rock's outermost surface.
Unfortunately, rocks are stubborn things and are't easy to break into pieces. Mining operations typically have huge facilities dedicated to milling, crushing, grinding, and processing rocks, and climate geoengineering based on artificially inducing rock weathering would have to rely heavily on these kinds of industrial facilities to crush the rocks. This geoengineering scheme would involving scaling up something far, far larger than the entire modern mining industry to mine rocks and crush the rocks. Only after millions of tons of rocks were mined and crushed could an artificial natural chemical weathering processes even be started on the broken rock fragments.
But wait a cotton-picking minute here----isn't one of the reasons we've have so much human-generated CO2 in the atmosphere in the first place that factories and industrial facilities around the planet release huge amounts of CO2? How is creating thousands of new mines dedicated to mining millions of tons of rocks, and then crushing the rocks in thousands of industrial facilities actually going to reduce CO2?
Clearly you would have to create a huge alternative carbon-fee energy system to power the huge mines, and this would be in addition to the creation of a huge alternative carbon-free energy system to power society, or this shame would wind up producing far more carbon then it pumps down.
I think mining for carbon reduction is an oxymoron.
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