I am also leery about spreading mountains of silica dust on fields where it can be blown in the air and end up in our lungs eventually. re phytoplankton/marine

I am also leery about spreading mountains of silica dust on fields where it can be blown in the air and end up in our lungs eventually. re phytoplankton/marine life: I guess basalt particles will sink. But if sinking is slow the top layer will get murky absorbing the light.