Добрый день, Коллеги. Важное сообщение, просьба принять участие. Музей Ферсмана ищет помощь для реставрационных работ в помещении. Подробности по ссылке
Sublevel caving (SLC) has previously been regarded as a high dilution and low recovery mining method requiring specific orebody geometry and rock mass conditions to be successful. Progress in the past 20 years at numerous operations has broken this misconception. A wide range of challenges have been encounteredand mitigated at operations around the world, including high stress and seismicity, fines, inrush hazard, remnant mining and interaction with open pits and other caves.
In 1988, at the request of members of the Society for Mining, Metallurgy, and Exploration (SME), Inc., the President of SME formed Working Party #79, Ore Reserve Definition, with the mission to develop guidelines for the public reporting of exploration information, resources, and reserves. A Subcommittee was appointed by the Working Party to draft these guidelines and submit recommendations to SME. The Subcommittee’s recommendations were published by SME in the April 1991 issue of “Mining Engineering”, and as a document entitled “A Guide for Reporting Exploration Information, Resources, and Reserves” in January 1992. Work continued on an ad-hoc basis until 1996, when Working Party #79 was renamed the SME Committee on Resources and Reserves and became a standing committee. <...>
Foraminifera have an evolutionary history that extends back to the Cambrian, more than 525 million years ago. Since then, they have radiated and evolved. To date, approximately 60,000 fossil and modern species have been validly recognized (LANGER, 2011), and an estimated 10,000 species (including only 40-50 planktonic species) are still living (VICKERMAN, 1992), constituting the most diverse group of shelled microorganisms in modern oceans (SEN GUPTA, 1999). These small-sized organisms, usually 0.1 to 1 mm, may be very abundant, and tens of thousands living specimens per square meter may be found in some environments (WETMORE, 1995). Their mineralized tests (shells) usually get preserved in the sediment after the death of the organism and may constitute a major, sometimes the dominant, part of many modern or fossil sediments (fig. 1). They are easy to collect, and their high-density populations provide an adequate statistical base, even in small volume samples, to perform environmental analyses, making them a powerful tool for environmental assessment. <...>
Geologists, also known as Geoscientists, are trying to understand the constitution of the earth. The surficial portion, which is directly visible to the geologists, is made up more of water bodies (the seas, the oceans, and the lakes, together constitute nearly 2/3rds of the entire surface of the earth) than the land masses (Africa, America, Asia etc.). Large area of land around the north and the southpoles, is covered with a thick blanket of ice sheet, throughout the year.
The Earth is approximately spherical, with a mean radius R = 6370km, a very small flattening (+7/ − 15km), mass 6 × 1024kg, and an average density 5.5g/cm3; the law of gravitational attraction is F = GmMr/r3, where F is the force directed along the separation distance r between two point bodies with mass m and M; and G = 6.67 × 10−8cm3/g · s2 is the gravitation constant.
The history of life is written in the rocks, or more precisely in the fossils contained within the rocks. Fossils are the remains of ancient animals and plants, as well as fungi and microbes, preserved by natural processes of burial and entombment. Without the existence of fossils it is doubtful whether Charles Darwin would ever have devised his theory of evolution by natural selection.
Oui choice of title for this book deliberately echoes Dseison’s A Hillary ofBritiih Earthquake!, which was published by the Cambridge University Press early in the 1920s. This was one of the first in recent tiroes to make a systematic study of seismic activity in a particular country, which we have tried to emulate for Iran. By calling our study a history we wish also to emphasise the importance оf time in the unfolding of geologic processes, and of investigating the past when attempting to under-&tand the present.
