Richard Gertsch

Use of TBM muck as construction material

Abstract Tunnel boring machines (TBMis) are widely used in tunnel construction in rock. The rock chips (muck) produced are rarely used for construction applications, however, because the suitability of the material is not well understood. Yet the cuttings appear to be of approximately the correct average size for some applications. If they are suitable in other respects, cost savings can be realized in tunnel construction, where aggregate is a common requirement. A review of standard construction aggregate specifications indicates that hardrock TBM much would be suitable for several construction applications with a minimum of processing: road pavement and structural concrete. Processing options also are discussed for cases where the raw TBM muck is nearly, but not quite, suitable. A 0.65 metric ton (1420 lb) cutting sample generated by a laboratory tunnel boring machine operating in a welded tuff is analyzed for suitability for different construction applications. In addition, numerous tunneling projects that use or have studied TBM waste for construction purposes are described.

Near-earth Resources

ABSTRACT: 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.

Surface Mine Design and Planning for Lunar Regolith Production

Terrestrial surface mine design and planning techniques are applied to the production of lunar regolith for manufacturing makeup gases for the life‐support system of a lunar base. Two scenarios are examined, due to the uncertainty of whether bound hydrogen sensed near the lunar poles is from cometary ice deposited in cold traps (♯1), or to hydrogen implanted within regolith grains by the solar wind (♯2). Scenario ♯1, with a total production requirement of 44 tonne/day of regolith, could be handled with four groups of four 6‐m3 capacity slushers (drag scrapers), each group extending 100 m around a single processing module. Scenario ♯2 (4.382 tonne/day) could be accomplished with three powered bowl‐type scrapers (capacity 24 m3) gathering the regolith into long windrows feeding a large processor. The present orebody model is extremely thin (1 m), although broad in extent: this prevents usage of high production‐rate systems such as large draglines.

Mining Near‐Earth Resources

ABSTRACT: Mining the potentially vast storehouse of natural resources contained within near‐Earth objects (NEOs) could assist mitigation of the danger that a threatening object presents to life on Earth. Properly planned, NEO mining could provide a substantial basis for the exploration and development of space, in addition to providing important tools and opportunities for mitigating impact hazards.

Asteroid/comet Classification for Mining Purposes

New information about the internal structures of asteroids and comets continues to be obtained. Meanwhile, renewed emphasis on exploration of the Solar System is sharpening the focus on extra-terrestrial raw materials to facilitate the process. The overall energy cost will be reduced significantly by maximizing usage of locally available resources. This paper refines a previously proposed classification of asteroids and comets for mining purposes, based on updated information about their mechanical properties. Class 0, ice composites, appears less homogeneous than before. Class 1, friable rock, may be the largest group, at the expense of Class 0 and especially Class 2, hard rock. Class 3 remains metallic, divided according to the amount of rock present. Additional information is needed for complete classification, so asteroid/comet mining operations can be planned realistically.

Total Ore Processing Integration and Management

A new dataset to illustrate ordinary, non-segregated operation of the mine and mill has been collected. Beginning in mid-November, it ended on 31 December, 2004. Drill monitoring data for several blast patterns is being analyzed. Figures 1 through 6 represent one of the patterns. Sample preparation for laboratory rock strength tests is underway, for comparison with the density and point-load test results measured last summer. The relationships among data mined from the databases and the ore segregation tests of both mines are being examined, mainly through use of multiple regression analysis. The study is ongoing.