#open-pit mining

[stone-cold-groove]

A day at the copper mine.

[crimsonpublishersminingscience]

Self-Assembling Photonic Crystals?

Various materials have dominated different human history periods. Some of them are even named by them: the Stone Age, Bronze Age, Iron Age… For example, in 5000 BC chisels made of copper (bronze is an alloy consisting primarily of copper) enabled the construction of Egyptian pyramids and sparked the growth of 1st great civilizations. From this perspective, the last century could be referred to as the Silicon Age. The “king” of this period, the silicon atom, is dressed with the electron cloud described by 1s2 2s2 2p6 3s2 3p2. Among these electrons, the outer four valence electrons, located at the 3s and 3p-orbital, are the most important for its “social” activities. These valence electrons can form a tetrahedral lattice crystal unit (Figure 1) characterized by a specific electronic band gap structure, displaying semiconducting electric behavior. This property is extremely useful, and due to its electronic semiconductors are at the heart of classical computers. The microelectronic revolution of the 20th century is based on sensitive control of electric currents in semiconductors, enabled by their band gap structure. The switching of logic functions relies on the number of electrons and holes below and above the band gap separating the valence and conducting band. Here the electronic band gap corresponds to a forbidden zone of energies that electrons cannot occupy. Among various semiconducting material, doped silicon is most commonly used. In addition to the band gap property, its main advantages with respect to competing materials were its natural abundance, optical transparency, and widespread use. In the 1980s first artificial photonic crystals appeared [1,2]. Crystal structures enabling sensitive manipulation of light beams have been demonstrated. Prototype photonic materials displayed periodic structures on a micrometer scale and possessed a photonic band gap. The latter is characterized by a window of optical wavelengths that cannot propagate through the otherwise optically transparent material. For example, the 1st photonic crystal was made by drilling a closely spaced array of sub micrometer sized cylindrical holes. These holes play a similar role as atoms in semiconductors. The band gap structure depends on the crystal symmetry and geometric parameters determining the crystal lattice. The parameters are tailored to yield the band gap in the visible wavelength regime. Again, as in the case of electric semiconductors, the tetrahedral geometry enabled desired properties, suggesting that this structure is outstanding for making a photonic band gap material. The general aim is to reproduce in photonic crystals analogous phenomena seen in electronic semiconductors. They should function as “semiconductors for light”. The key to this in the band gap structure, which is dictated by geometry. Note that the behavior of i) electrons and ii) light beams in i) electronic semiconductors and ii) photonic materials is governed by different basic equations: i) Schrodinger equation and ii) Maxwell equations, respectively.

Read more about this article: https://crimsonpublishers.com/amms/fulltext/AMMS.000620.php

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[crispywizardtale]

[jaarijani]

✨CUTE✨

[manessha545]

Chuquicamata, Chile: Chuquicamata is the largest open pit copper mine in terms of excavated volume in the world. It is located in the north of Chile, just outside Calama, at 2,850 m above sea level. It is 215 km northeast of Antofagasta and 1,240 km north of the capital, Santiago. Wikipedia

[meriol-lehmann]

chemin saint-claude, val-des-sources

[naritaren]

My haul from today. I also got some other smaller things, but this is the fiber.

I'm super excited about the orange one because it's called Taconite and I spent 10 years living literal miles from taconite mines! I've been to the mines and stuff!

I'm excited

[burningcomputerpersona]

ALL SEVEN MINUTES AND FIFTY ONE SECONDS OF UNTITLED LIVE. AND IT WAS EVEN BETTER THAN I'D EVER EXPECTED

[eopederson]

Morenci Mine, Greenlee County, 2014.

[tilbageidanmark]

What coal mining was like

[freddyyeti]

KITSCHY SCREEN TIME LIMITING APPS ARE BACK ON THE MENU BOYS 🗣️‼️

[crimsonpublishersminingscience]

Estimating Coal Strength Based on Historical Laboratory Tests and Geomechanics Classification

The coal seam strength and the failure criteria that represents the behavior of the coal seam are very important for mine section and pillar design. In addition, the same to roof and floor layers, which will form the roof-pillar-floor system. Therefore, the rock mass characterization is the most important job and it is the beginning of the underground ground control design. Another issue is the distribution or behavior of the coal seam strength for the whole mine area. Sometime, the coal seam strength assumed the same for entire area, but it is not true because the coal seam is heterogenic and anisotropic, and also the coal strength gets some effects due to faults and spacing between fractures. This paper has the objective to demonstrate the use of themethodology for geomechanics characterization to determine the strength for the Bonito coal seam and discuss the coal seam strength distribution around the entire mine area. The intact coal strength considered the laboratory tests that were proceeded during the lasts 17 years, including triaxial and uniaxial strength tests. It was note that there is a strong correlation between all laboratory strength tests with 90% of interval confidence. The explanation for this coal seam strength variation is the presence of the discontinuities and their variation in quantity and quality at each location in the mine area because the coal seam rock classification and its behavior will be affected by the quantity and quality of fractures.

Read more about this article: https://crimsonpublishers.com/amms/fulltext/AMMS.000618.php

Read more about this journal: https://crimsonpublishers.com/amms/

[show-me-hole]

The Big Hole, Kimberly Mine, Northern Cape, Kimberly, South Africa.

In operation from 1871-1914, The Kimberly Mine was an open pit diamond mine with a maximum depth of 240 meters (790 ft). Most of the miners were Bathoso (one of the many ethnic groups oppressed, abused, and dehumanized during the apartheid) men who associated mining with death and danger (as one should). A miner's poem follows:

"Death does not choose; famine chooses.

I was going to my mother quietly:

"Mother, take a letter for me,

I am going to DeBeers (mines).

Scarify me with qetella pele

['finish first' medicine],

So that these multitudes should follow my lead."

Other men's villages are not entered freely,

Lad, the day I'm going, I mount to ride away,

A woman of witchcraft was already hard at work;

I saw her early going to the graveyard,

She puts on a string skirt fastened with knots,

She takes the arm of the corpse and waves it,

A mouthful of blood, she spits into the air,

She says, "Men gone to DeBeers.

They can come home dead from the mines."

To me, Child of Rakhali

I am not dead; even now I still live,

I am a wanderer of the mines; Sootho"

— Coplan 1995: 33

Those who died in the mine were buried in unmarked, mass graves. Their history shall not be erased.

[Feel free to add corrections and additional information concerning apartheid, the Kimberly Mine and/or the Bathoso.]

[gaymarisa]

baby's first battle vest <3 i scraped this entire thing together in 4 days and i have pretty much been wearing it since... i have way more patches and more things i wanna do with it, but it's passable for the festival season in this state and it has already been thoroughly mosh pit tested so i am quite happy with it

[anonymusbosch]

depending on how deranged i feel when i get back from work tomorrow there may or may not be a post about the LA times solar development joshua tree article. it already exists in my head but i would want to do it justice. the article is so misleading I would want to accuse it of being malicious

[meriol-lehmann]

chemin saint-claude, val-des-sources