7.  Is there such a region that is suitably remote and controllable, and that can handle the logistics of secret nuclear weapons testing?

•  Can secrecy be successfully imposed on all of the people involved in the cross-cutting technologies of a clandestine test program, and on all who need to know of its technical results?

•  Can the tester avoid compromising security by conducting a nuclear test in a region containing a hostile ethnic group or a civil war? Can the test be conducted outside one’s own territory?

8.  Can nuclear explosions of large enough yield be carried out secretly, and repeated as necessary, to support the development of a deployable weapon?

•  Can those carrying out the decoupled test be sure that the yield will not be larger than planned, and thus only partially decoupled?

•  Can a minimum of drill holes, cables, and specialized equipment be used and yet obtain necessary information about the characteristics of nuclear device (s).

•  Can the site be cleaned up before an on-site inspection team arrives?

9.  Can a clandestine test in a mining area be hidden in one of a series of ongoing large chemical explosions?

•  Can suitable rock for a decoupled test be found below coal, other minerals and sedimentary rock in which large chemical explosions are used in mining?

Mine Masking

The 2002 Report briefly described the possibility of evasive nuclear-explosion testing in an active mining region. Many types of mining operations routinely use chemical explosives, sometimes in impressively large amounts (exceeding ten kilotons of chemical explosive for some shots, and annual totals amounting to megatons of explosive per year for the largest industrial countries). An issue of concern in the early 1990s was whether large mine blasts might generate seismic signals in such numbers that efforts at CTBT monitoring for nuclear explosions could be overwhelmed, but it later became understood and accepted that the commercial purpose of mine blasting entails practices that greatly reduce seismic amplitudes and only a small fraction of mine blasts would even be detected. The issue with mine-blast signals then became whether detectable blasting activity could be used to mask or disguise the signals from an underground nuclear explosion. This section provides further details, additional references to papers and a website that describe relevant aspects of the seismic signals from chemical explosions, and some specific mining regions where blasting activity is detected at monitoring networks, and summarizes assessments of the size of the largest underground nuclear explosion whose seismic signals might be successfully masked by mine-blasting.

To estimate the overall scale of mine blasting Richards et al. (1992) surveyed blasting operations in the mining industry (emphasizing the United States, with operations in Russia and Europe being comparable) and concluded: “The main point…from the perspective of those concerned with nuclear explosion monitoring and the question of discriminating between chemical and nuclear explosions, is that a large industrialized country can be expected to carry out large numbers of chemical explosions.” The industry would call a shot larger than 50 tons “large,” and on the order of 30 such shots occur each day in the United States, including one at 200 tons or even larger. Several shots at the kiloton level occur each month, and some amount to more than ten kilotons. A key point is that almost all industrial shots larger than 1 ton are “ripple fired” with the total charge broken up into much smaller units, typically less than 100 kilograms (0.0001 kilotons) of chemical explosive, that are fired in sequence to achieve the commercial purpose of breaking or moving large amounts of rock. For the largest chemical explosions, the sequence of separate blasts typically takes tens of seconds to execute. A net

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