Hugh Pickens writes: "Earlier this summer when three Chinese scientists descended to a depth of more than 0.6 leagues under the sea in a craft the size of a small truck and planted their nation’s flag on the dark seabed at 3,759 meters, they signaled Beijing's intention to take the lead in exploring remote and inaccessible parts of the ocean floor which are rich in oil, minerals and other resources that the Chinese would like to mine. "They're in it for a penny and a pound," says Dr. Don Walsh, a pioneer of deep-ocean diving. "It's a very deliberate program." The global seabed is littered with what experts say is trillions of dollars' worth of mineral nodules as well as many objects of intelligence value: undersea cables carrying diplomatic communications, lost nuclear arms, sunken submarines and hundreds of warheads left over from missile tests. The small craft that made the trip — named Jiaolong, after a mythical sea dragon — is meant to go as deep as 7,000 meters, or 4.35 miles, edging out the current global leader but China is moving cautiously, its dives going deeper in increments. "They're being very cautious," Walsh adds. "They respect what they don't know and are working hard to learn."""