Comments:BP: Plug for underwater oil leak in Gulf of Mexico fails
I believe crude but maybe effective way of eventually containing the BP Gulf of Mexico oil leak would be to create a ”sarcophagus" containment around the leak site just as the Russians did with the Chernobyl nuclear accident, some years ago.
My idea is to build a rock cap (granite or otherwise) made up of progressively smaller boulders (automobile-size at first) over the leak site on the sea bed. Do this by using a robot-assisted-lowering by crane method. This cap would need to be substantial enough by its own weight to contain the oil leak, once the remaining steps are taken.
The remaining steps would be to continue building this sarcophagus in height encasing the leak site adding more and more boulders until the site is covered in boulders at least 20-meters thick. Once the initial cap is built covering the site at least by 20 meters of boulders, the oil leak will disperse into many channels, each with less pressure. The lessened pressure will allow for easier containment.
Containment would begin by filling in the initial cap layer with progressively smaller boulders interspersed amidst the bigger boulders. Do this until ultimately an effective seal is made using concrete as an additive. During this process crane-robot assist of "plastic sealed bags of concrete" that could be depth-charged-ignited or ripped open by robot or some other trigger when in position above the boulders. The concrete would solidify eventually among the smaller boulders, where successively smaller boulders leave gaps in the sarcophagus. Also, the mud-jack pumps that BP was using in their first containment effort, might also are a method of delivering concrete slurry.
The plan is to build a cap base and as you are building it making it a solid wall. Plus the site may have to be substantial in height and thickness to build up under-water weight-sealing pressure to stop the oil flow. I believe the concrete slurry would solidify even under water as it does on land, when for example making a sidewalk and even standing water does not prevent the concrete from setting-up.
I would imagine the height would have to be maybe 40-meters above the leak site to be effective. And important part of this procedure would be that as the cap is built it adds strength and resistance in terms of a side-wall and "heavy lid" so to speak.