Bin hopper engineering and bulk materials flow : a state-of-the-art report on empirical and theoretical analyses /

Includes bibliographical references (p. 35-36).Mode of access: Internet

In situ stress measurements near the Ross shaft pillar, Homestake Mine, South Dakota /

Includes bibliographical references (p. 15).Mode of access: Internet

Near-Earth Resources

The technologies required to detect, track, categorize, and intercept objects in Earth-impacting orbits can also provide access to their rich storehouse of materials. Mitigation of a clear and present near-Earth object (NEO) threat to the Earth must provide the greatest assurance of success with the least risk to the planet. in some cases, mining a threatening NEO may become a viable alternative or supplement to a deflection or interception scenario. This converts the NEO threat to a near-Earth resource. NEOs can supply materials for a wide range of operations both in space and on Earth, as they are thought to contain large amounts of water, carbon, structural metals, industrial feedstocks of many types, and precious metals. This wealth has low overhead for utilization in space; some known NEOs would require lower transportation energy expenditure than lunar resources. Mining a NEO inherently requires, among other things, altering the mass distribution of the body during exposure, removal, and processing of the ore. These processes can be tailored to facilitate deflection of the body from Earth impact by altering its orbital characteristics. the advantage of NEO mining is that it can mitigate the threat - the primary effort - while converting it into resources for space exploration. This additional effort, within an appropriate time scale, allows sequential mitigation of the NEO in a controlled manner while providing the resources contained within the NEO for use either in space or on Earth. Both goals, to be successful, will require maximum utilization of all sources of knowledge. the two most important are an extensive reconnaissance of the target NEO and the long history of terrestrial mining practice. This paper discusses how current mining technology might be adapted to mine NEOs, whether threatening or not. It summarizes our knowledge of NEO composition, physical properties, and mining and processing methods, and points out areas where further research, especially physical testing in space, is vital. the great potential of NEO resources and the successful mitigation of NEO threats will be best realized if their utilization is considered from the earliest planning of Earth-NEO mitigations