1000 resultados para trajectory mining


Relevância:

20.00% 20.00%

Publicador:

Resumo:

While the 1913-1914 copper country miners’ strike undoubtedly plays an important role in the identity of the Keweenaw Peninsula, it is worth noting that the model of mining corporations employing large numbers of laborers was not a foregone conclusion in the history of American mining. Between 1807 and 1847, public mineral lands in Missouri, in the Upper Mississippi Valley, and along the southern shore of Lake Superior were reserved from sale and subject to administration by the nation’s executive branch. By decree of the federal government, miners in these regions were lessees, not landowners. Yet, in the Wisconsin lead region especially, federal authorities reserved for independent “diggers” the right to prospect virtually unencumbered. In doing so, they preserved a comparatively egalitarian system in which the ability to operate was determined as much by luck as by financial resources. A series of revolts against federal authority in the early nineteenth century gradually encouraged officers in Washington to build a system in the copper country in which only wealthy investors could marshal the resources to both obtain permits and actually commence mining operations. This paper will therefore explore the role of the federal government in establishing a leasing system for public mineral lands in the years previous to the California Gold Rush, highlighting the development of corporate mining which ultimately set a stage for the wave of miners’ strikes in the late nineteenth and early twentieth centuries.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

During the second half of the nineteenth century fraternal and benevolent associations of numerous descriptions grew and prospered in mining communities everywhere. They played an important, but neglected role, in assisting transatlantic migration and movement between mining districts as well as building social capital within emerging mining communities. They helped to build bridges between different ethnic communities, provided conduits between labour and management, and networked miners into the non-mining community. Their influence spread beyond the adult males that made up most of their membership to their wives and families and provided levels of social and economic support otherwise unobtainable at that time. Of course, the influence of these organisations could also be divisive where certain groups or religions were excluded and they may have worked to exacerbate, as much as ameliorate, the problems of community development. This paper will examine some of these issues by looking particularly at the role of Freemasonry and Oddfellowry in Cornwall, Calumet, and Nevada City between 1860 and 1900. Work on fraternity in the Keweenaw was undertaken in Houghton some years ago with a grant from the Copper Country Archive and has since been continued by privately funded research in California and other Western mining states. Some British aspects of this research can be found in my article on mining industrial relations in Labour History Review April 2006

Relevância:

20.00% 20.00%

Publicador:

Resumo:

With the insatiable curiosity of human beings to explore the universe and our solar system, it is essential to benefit from larger propulsion capabilities to execute efficient transfers and carry more scientific equipment. In the field of space trajectory optimization the fundamental advances in using low-thrust propulsion and exploiting the multi-body dynamics has played pivotal role in designing efficient space mission trajectories. The former provides larger cumulative momentum change in comparison with the conventional chemical propulsion whereas the latter results in almost ballistic trajectories with negligible amount of propellant. However, the problem of space trajectory design translates into an optimal control problem which is, in general, time-consuming and very difficult to solve. Therefore, the goal of the thesis is to address the above problem by developing a methodology to simplify and facilitate the process of finding initial low-thrust trajectories in both two-body and multi-body environments. This initial solution will not only provide mission designers with a better understanding of the problem and solution but also serves as a good initial guess for high-fidelity optimal control solvers and increases their convergence rate. Almost all of the high-fidelity solvers enjoy the existence of an initial guess that already satisfies the equations of motion and some of the most important constraints. Despite the nonlinear nature of the problem, it is sought to find a robust technique for a wide range of typical low-thrust transfers with reduced computational intensity. Another important aspect of our developed methodology is the representation of low-thrust trajectories by Fourier series with which the number of design variables reduces significantly. Emphasis is given on simplifying the equations of motion to the possible extent and avoid approximating the controls. These facts contribute to speeding up the solution finding procedure. Several example applications of two and three-dimensional two-body low-thrust transfers are considered. In addition, in the multi-body dynamic, and in particular the restricted-three-body dynamic, several Earth-to-Moon low-thrust transfers are investigated.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Cardwell Mining District is part of the greater Whitehall Mining District. The district is situated about four miles to the east and northeast of Whitehall in the southern end of the Bull Mountains which are near the Continental Divide. The first reported production was in 1896 after the dis­covery of the Mayflower Mine. Mining has been carried on in­termittently and on a small scale since that time.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This report includes the results of geological investigation of a small area in the northern part of the Argenta mining district. Approximately two square miles were mapped. The underground working of the three mines only were accessible: the Goldfinch. Golden Era, and Mayday mines.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

It is surprising to learn that so large a variety of igneous rocks is present in the Jardine and Crevasse Mountain mining districts, a region that is generally thought of as consisting principally of schists.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

From 1888 until 1893 the district was a booming mining camp. Seven stamp mills were running and ore was be­ing mined from the Independence, King Solomon, Poorman, Golden, Hidden Treasure and Crown claims. The town of Independence, which was on the Boulder River at the fork of Basin Creek, boasted a population of 400 people.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This report includes the results of geological investigation of the Clinton Mining District and the Hidden Treasure Mine.The Clinton Mining District is an unorganized mining dis­trict situated in the Garnet Range two and one-half miles northeast of the town of Clinton, Montana, which is on the Northern Pacific Railway and the Chicago, Milwaukee, St. Paul, and Pacific Railroad seventeen miles east of the city of Missoula. The district is in the same range of mountains as the Gar­net Mining District and the drainage from the district covered is to the south into the Hell Gate or Clarks Fork of the Colum­bia River. The main stream is known as Trail creek, which runs in a southerly direction from the area studied.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Purpose of this thesis was to investigate the possibility of concentrating scheelite from Wilfley table gold concentrates from the mill of the Jardine Mining Company; and to determine whether such concentration is economically feasible and the product of sufficiently high grade to meet commercial specifications for such a product.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper is a report of a geological survey made of an area of approximately fifty square miles lying Northeast of Whitehall, Montana, in the region of the Golden Sun­light Mine. The survey was made by a field party consisting of twenty-three members of the senior class of the Montana School of Mines.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Koyukuk Mining District was one of several northern, turn of the century, gold rush regions. Miners focused their efforts in this region on the Middle Fork of the Koyukuk River and on several of its tributaries. Mining in the Koyukuk began in the 1880s and the first rush occurred in 1898. Continued mining throughout the early decades of the 1900s has resulted in an historic mining landscape consisting of structures, equipment, mining shafts, waste rock, trash scatters, and prospect pits. Modern work continues in the region alongside these historic resources. An archaeological survey was completed in 2012 as part of an Abandoned Mine Lands survey undergone with the Bureau of Land Management, Michigan Technological University, and the University of Alaska Anchorage. This thesis examines the discrepancy between the size of mining operations and their respective successes in the region while also providing an historical background on the region and reports on the historical resources present.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The purpose of this thesis is to analyze the evolution of an early 20th century mining system in Spitsbergen as applied by Boston-based Arctic Coal Company (ACC). This analysis will address the following questions: Did the system evolve in a linear, technological-based fashion? Or was the progression more a product of interactions and negotiations with the natural and human landscapes present during the time of occupation? Answers to these questions will be sought through review of historical records and material residues identified during the 2008 field examination on Spitsbergen. The Arctic Coal Company’s flagship mine, ACC Mine No. 1, will serve as the focus for this analysis. The mine was the company’s largest undertaking during its occupation of Longyear Valley and today exhibits a large collection of related features and artifacts. The study will emphasize on the material record within an analysis of technical, environmental and social influences that guided the course of the mining system. The intent of this thesis is a better understanding of how a particular resource extraction industry took root in the Arctic.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This lecture discusses monitoring activities of the Berkeley Pit for the past 31 years at the Montana Bureau of Mines and Geology in Butte, Montana.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Tuxedo mining district lies fifteen miles west of Butte on the south east end of Deer Lodge valley. Prospecting and mining has been carried on in this district for about 20 years. As a result many pits have been dug, several adits have been driven, and two or three shallow shafts have been sunk.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVE: A substantial proportion of patients develop posttraumatic stress disorder (PTSD) following myocardial infarction (MI). Previous research on the trajectory over time of PTSD in post-MI patients is scant and refers to self-rated posttraumatic symptoms. The aim of this study was to investigate the longitudinal course of an interviewer-rated diagnosis of PTSD and PTSD symptom severity following MI. METHODS: Study participants were 40 patients (78% men, mean age 54 +/- 8 years) who were diagnosed with PTSD using the Clinician-administered PTSD Scale (CAPS) after an average of 5 +/- 4 months (range 2-16 months) following an index MI. After a mean follow-up of 26 +/- 6 months (range 12-36 months), 24 patients underwent a second diagnostic interview. RESULTS: Two-thirds of patients (n = 16) still qualified for a diagnosis of PTSD at follow-up. In all 24 patients, total PTSD symptoms (p = 0.001), re-experiencing symptoms (p < 0.001), avoidance symptoms (p = 0.015), and, with borderline significance, hyperarousal symptoms (p < 0.06) had all decreased over time. However, in the subgroup of the 16 patients who had retained PTSD diagnostic status at follow-up, symptoms of avoidance (p = 0.23) and of hyperarousal (p = 0.48) showed no longitudinal decline. Longer duration of follow-up was associated with a greater decrease in avoidance symptoms (p = 0.029) and, with borderline significance, in re-experiencing symptoms (p < 0.07) across all patients. CONCLUSION: Although PTSD symptomatology waned over time and in relation to longer follow-up, two-thirds of patients still qualified for a diagnosis of PTSD 2 years after the initial diagnosis. In post-MI patients, clinical PTSD is a considerably persistent condition.