for soft rock and large diameter holes

См. также в других словарях:

• sedimentary rock — Rock formed at or near the Earth s surface by the accumulation and lithification of fragments of preexisting rocks or by precipitation from solution at normal surface temperatures. Sedimentary rocks can be formed only where sediments are… …   Universalium

• tunnels and underground excavations — ▪ engineering Introduction        Great tunnels of the world Great tunnels of the worldhorizontal underground passageway produced by excavation or occasionally by nature s action in dissolving a soluble rock, such as limestone. A vertical opening …   Universalium

• Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics       Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity.       Computer scientist Manindra Agrawal of the… …   Universalium

• Architecture and Civil Engineering — ▪ 2009 Introduction Architecture       For Notable Civil Engineering Projects in work or completed in 2008, see Table (Notable Civil Engineering Projects (in work or completed, 2008)).        Beijing was the centre of the world of architecture… …   Universalium

• Underground mining (hard rock) — A three dimensional model of an underground mine with shaft access Underground hard rock mining refers to various underground mining techniques used to excavate hard minerals, mainly those containing metals[1] such as ore containing gold …   Wikipedia

• building construction — Techniques and industry involved in the assembly and erection of structures. Early humans built primarily for shelter, using simple methods. Building materials came from the land, and fabrication was dictated by the limits of the materials and… …   Universalium

• materials science — the study of the characteristics and uses of various materials, as glass, plastics, and metals. [1960 65] * * * Study of the properties of solid materials and how those properties are determined by the material s composition and structure, both… …   Universalium

• Landslide mitigation — Landslides can be triggered by many often concomitant causes. In addition to shallow erosion or reduction of shear strength caused by seasonal rainfall, causes triggered by anthropic activities such as adding excessive weight above the slope,… …   Wikipedia

• Drilling rig — For a detailed diagram of a Petroleum drilling rig, see List of components of oil drilling rigs. Drilling rig preparing rock blasting …   Wikipedia

• Fossil — For other uses, see Fossil (disambiguation). Three small ammonite fossils, each approximately 1.5 cm across …   Wikipedia

• Tent — For the tetanus neurotoxin (TeNT), see Tetanospasmin. A modern two person, lightweight hiking dome tent; it is tied to rocks as there is nowhere to drive stakes on this rock shelf A tent is a shelter consisting of sheets of fabric or other… …   Wikipedia