Many modern skin-care trends are impossible to follow. She cites the barrage of glowing skin trends born out of social media. You might feel as though your skin is the problem, instead of the unattainable goal. Instead, we can form our own nuanced take. There is also a common misconception that glowing skin equals healthy skin.
Images of healthy people have traditionally also showed tanned skin, but we now know that a tan is a sign of sun damage and a risk factor for skin cancer, so some of these images have a lot to answer for.
Glow-enhancing skin-care products could actually be hurting your skin. While there are countless products that can boost brightness and sheen, flawless skin trends may actually contribute to the multitude of issues experts are seeing.
This is especially true when it comes to brightening ingredients such as vitamin C, retinol, and exfoliating acids, all of which have the potential to irritate skin when overused. With that said, loading on the active ingredients could be doing more harm than good. She pinpoints red, dry, flaky, irritated skin, as well as a damaged skin barrier, as issues that can arise. When it comes to skin conditions, Gillies says that acne, rosacea, and psoriasis affect millions of people all over the world; in fact, they seem to be more common than ever.
How could that not have an impact on our mental health? Kluk mentions that it would be beneficial to see a more even playing field in how skin is depicted, especially on social media, as this might relieve pressure and self-criticism. Just last week, the BBC reported that the Advertising Standards Authority ASA told influencers not to apply filters to social-media adverts if they exaggerate the effect of skin care or cosmetics.
View this post on Instagram A post shared by Real Skin Club therealskinclub Gillies also recently launched the Real Skin Club, which aims to spread skin positivity to those who need it most. You are much more than your appearance. Kluk, who has experienced acne herself, says that taking a level-headed approach is the key to accepting and being happy with your skin.
The more pictures we post of our events, activities, new haircuts, or holidays on social media, the more time we spend looking at ourselves through the eyes of other people and judging ourselves. Like what you see? How about some more R29 goodness, right here? TYL earnings call for the period ending December 31, The annual awards include companies of all sizes, from startups to enterprise, nationally and in the eight largest tech markets.
French President Emmanuel Macron told US President Joe Biden that the leaders could broker a settlement to the long-running trade dispute between Boeing and Airbus, according to a media report on Wednesday. The Mets and Yankees released statements on Wednesday in response to the news that arenas in New York will be permitted to reopen at partial capacity starting on Feb.
Now North Carolina is playing seven games against nonconference opponents with hopes of securing a high seed for the NCAA tournament. John Bel Edwards disagrees with President Joe Biden's targeting of fossil fuel industries and wants the White House to reconsider its decision to pause new oil and gas drilling leases in the Gulf of Mexico, the Louisiana governor's administration said Wednesday.
Biden's approach to oil and gas strikes at one of Louisiana's economic engines and an industry that is a chief financial backer of the state's coastal restoration work, putting the Democratic governor at odds with a president within his own party. The governor's top lawyer, coastal adviser and natural resources secretary told state lawmakers that Edwards thinks Biden's moratorium on new oil and gas drilling leases on federal land and waters is the wrong approach to combat climate change.
Students seeking to attend hyper-competitive Lowell H. Malcolm D. Tully and Kate fans need to know! Chase Elliott perhaps offered a sneak preview of what's to come in his title defense when he knocked Ryan Blaney out of his way in the closing stretch of the Busch Clash. The two are tight — they vacation together — and Elliott had little remorse. Some social media users are attributing a mixed-up sharing of the proverb about teaching a man to fish to President Joe Biden.
That is false. Read full article. Newsfile Corp. Story continues. Latest Stories. Motley Fool. PR Newswire. Business Wire. Associated Press. Yahoo Sports. NBC News. The surface RC drilling was largely focused on establishing continuity of the Footwall ….
The surface RC drilling was largely focused on establishing continuity of the Footwall and Copperstone zone mineralization. We are again using the opportunity to continue with the discovery of the new Footwall zone. Drilling results to date clearly demonstrate the Footwall and Copperstone zones remain open and indicate further expansion of gold mineralized zones along strike and dip with future drilling. Using the same target identification methodologies as for our prior programs, we expected to achieve similar results and, so far, we have.
The underground core drilling is designed to expand resources by drilling for strike and down dip extensions including some portion of infill of previously drilled gold mineral domains, following up on what was a very successful 5, meter drilling program. Two drill rigs were employed. The program was a continuation of the successful drilling program performed by the Company. The drilling results confirm continuity of gold mineralization in the Footwall and Copperstone zones intersecting gold mineralization at expected gold grades and higher widths where anticipated while remaining open along strike and dip.
The following provides additional information for each of the drill holes reported above:. AZGS is an angle hole collared in the Southern portion of the pit east wall, designed primarily to test the strike continuity of gold mineralization within the B zone of the Copperstone zone and test possible parallel Footwall zone extensions m below. The hole extended the strike continuity, at its modelled depth location from the Copperstone zone ALW4 mineralized domain, by 30m to the southeast.
The hole, from m, intercepted 3. Anomalous gold grades were intercepted deeper in the hole, which may indicate additional gold mineralization at depth. The hole successfully demonstrates better continuity between the A and B zones than previously known; the area is under-drilled. AZGS is an angle hole collared in the Southwestern portion of the pit, drilled southwesterly to test the continuity of multiple mineralized domains in the Footwall zone.
At This intercept indicates 3. Further, this high grade intercept may prove to expand gold mineralization up to a high grade historic hole located about 47 m to the southwest. Other modelled domains were intersected higher in the hole, which successfully established strike continuity of gold mineralization. AZGS is an angle hole collared in the Southwestern portion of the pit, successfully tested the continuity of multiple mineralized domains in the Footwall zone.
From The Footwall zone FW02 domain was intersected about Cut-off grades, or better, near the top of hole successfully indicate a potential new gold domain in the Footwall zone. AZGS is an angle hole collared in the Southwestern portion of the pit, successfully tested the up-dip extension of multiple mineralized domains in the Footwall zone. The Footwall zone FW05 domain was successfully intersected about 3. Au The Footwall zone FW02 domain was successfully intersected about AZGS is a vertical hole drilled in the Southwest area of the pit, targeting Footwall zone mineralization.
The indicated true thickness is 3. The intercept is an effective strike extension of approximately 30 m to the southeast, extending the edge of this Inferred area of the Footwall zone marked by historic drill hole KERS AZGS is an angle hole drilled southwesterly, successfully testing the continuity of gold mineralization in the Footwall zone in an up-dip direction.
These results demonstrate up dip continuity from KERS of about m. Also, at Each intercept effectively resulted in an up-dip extension of gold mineralization, from historic KERS, of approximately 61 m. AZGS is a vertical hole drilled in the Southwest area of the pit, confirming Footwall zone gold mineralization continuity. This is a m up dip expansion from historic KERS and This is an approximately 61 m up-dip extension of mineralized shear from historic KERS It was drilled for the purpose of confirming the orebody in this B zone area of the Copperstone zone.
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By , this was halved again to If you want to keep track of precisely when these halvings will occur, you can consult the Bitcoin Clock , which updates this information in real-time. Interestingly, the market price of bitcoin has, throughout its history, tended to correspond closely to the reduction of new coins entered into circulation.
This lowering inflation rate increased scarcity and historically the price has risen with it. Although early on in Bitcoin's history individuals may have been able to compete for blocks with a regular at-home computer, this is no longer the case. The reason for this is that the difficulty of mining Bitcoin changes over time. In order to ensure the smooth functioning of the blockchain and its ability to process and verify transactions, the Bitcoin network aims to have one block produced every 10 minutes or so.
However, if there are one million mining rigs competing to solve the hash problem, they'll likely reach a solution faster than a scenario in which 10 mining rigs are working on the same problem. For that reason, Bitcoin is designed to evaluate and adjust the difficulty of mining every 2, blocks, or roughly every two weeks. When there is more computing power collectively working to mine for Bitcoin, the difficulty level of mining increases in order to keep block production at a stable rate.
Less computing power means the difficulty level decreases. To get a sense of just how much computing power is involved, when Bitcoin launched in the initial difficulty level was one. As of Nov. All of this is to say that, in order to mine competitively, miners must now invest in powerful computer equipment like a GPU graphics processing unit or, more realistically, an application-specific integrated circuit ASIC.
The photo below is a makeshift, home-made mining machine. The graphics cards are those rectangular blocks with whirring fans. Note the sandwich twist-ties holding the graphics cards to the metal pole. This is probably not the most efficient way to mine, and as you can guess, many miners are in it as much for the fun and challenge as for the money. The ins and outs of bitcoin mining can be difficult to understand as is. And there is no limit to how many guesses they get.
Let's say I'm thinking of the number There is no "extra credit" for Friend B, even though B's answer was closer to the target answer of Now imagine that I pose the "guess what number I'm thinking of" question, but I'm not asking just three friends, and I'm not thinking of a number between 1 and Rather, I'm asking millions of would-be miners and I'm thinking of a digit hexadecimal number.
Now you see that it's going to be extremely hard to guess the right answer. In Bitcoin terms, simultaneous answers occur frequently, but at the end of the day, there can only be one winning answer. Typically, it is the miner who has done the most work or, in other words, the one that verifies the most transactions. The losing block then becomes an " orphan block. Miners who successfully solve the hash problem but who haven't verified the most transactions are not rewarded with bitcoin.
Well, here is an example of such a number:. The number above has 64 digits. Easy enough to understand so far. As you probably noticed, that number consists not just of numbers, but also letters of the alphabet. Why is that? To understand what these letters are doing in the middle of numbers, let's unpack the word "hexadecimal.
As you know, we use the "decimal" system, which means it is base This, in turn, means that every digit of a multi-digit number has 10 possibilities, zero through nine. In a hexadecimal system, each digit has 16 possibilities.
But our numeric system only offers 10 ways of representing numbers zero through nine. That's why you have to stick letters in, specifically letters a, b, c, d, e, and f. If you are mining bitcoin, you do not need to calculate the total value of that digit number the hash. I repeat: You do not need to calculate the total value of a hash. Remember that ELI5 analogy, where I wrote the number 19 on a piece of paper and put it in a sealed envelope?
In bitcoin mining terms, that metaphorical undisclosed number in the envelope is called the target hash. What miners are doing with those huge computers and dozens of cooling fans is guessing at the target hash. A nonce is short for "number only used once," and the nonce is the key to generating these bit hexadecimal numbers I keep talking about. In Bitcoin mining, a nonce is 32 bits in size—much smaller than the hash, which is bits.
In theory, you could achieve the same goal by rolling a sided die 64 times to arrive at random numbers, but why on earth would you want to do that? The screenshot below, taken from the site Blockchain. You are looking at a summary of everything that happened when block was mined. The nonce that generated the "winning" hash was The target hash is shown on top.
The term "Relayed by Antpool" refers to the fact that this particular block was completed by AntPool, one of the more successful mining pools more about mining pools below. As you see here, their contribution to the Bitcoin community is that they confirmed transactions for this block.
If you really want to see all of those transactions for this block, go to this page and scroll down to the heading "Transactions. All target hashes begin with zeros—at least eight zeros and up to 63 zeros. There is no minimum target, but there is a maximum target set by the Bitcoin Protocol. No target can be greater than this number:. Here are some examples of randomized hashes and the criteria for whether they will lead to success for the miner:.
You'd have to get a fast mining rig, or, more realistically, join a mining pool—a group of coin miners who combine their computing power and split the mined bitcoin. Mining pools are comparable to those Powerball clubs whose members buy lottery tickets en masse and agree to share any winnings. A disproportionately large number of blocks are mined by pools rather than by individual miners. In other words, it's literally just a numbers game. You cannot guess the pattern or make a prediction based on previous target hashes.
Not great odds if you're working on your own, even with a tremendously powerful mining rig. Not only do miners have to factor in the costs associated with expensive equipment necessary to stand a chance of solving a hash problem. They must also consider the significant amount of electrical power mining rigs utilize in generating vast quantities of nonces in search of the solution.
All told, bitcoin mining is largely unprofitable for most individual miners as of this writing. Source: Cryptocompare. Mining rewards are paid to the miner who discovers a solution to the puzzle first, and the probability that a participant will be the one to discover the solution is equal to the portion of the total mining power on the network. Participants with a small percentage of the mining power stand a very small chance of discovering the next block on their own.
For instance, a mining card that one could purchase for a couple of thousand dollars would represent less than 0. With such a small chance at finding the next block, it could be a long time before that miner finds a block, and the difficulty going up makes things even worse. The miner may never recoup their investment. The answer to this problem is mining pools. By working together in a pool and sharing the payouts among all participants, miners can get a steady flow of bitcoin starting the day they activate their miner.
As mentioned above, the easiest way to acquire bitcoin is to simply buy it on one of the many exchanges. Alternately, you can always leverage the "pickaxe strategy. Or, to put it in modern terms, invest in the companies that manufacture those pickaxes. In a cryptocurrency context, the pickaxe equivalent would be a company that manufactures equipment used for Bitcoin mining.
The legality of Bitcoin mining depends entirely on your geographic location. The concept of Bitcoin can threaten the dominance of fiat currencies and government control over the financial markets. For this reason, Bitcoin is completely illegal in certain places. Bitcoin ownership and mining are legal in more countries than not. The risks of mining are that of financial risk and a regulatory one. As mentioned, Bitcoin mining, and mining in general, is a financial risk. One could go through all the effort of purchasing hundreds or thousands of dollars worth of mining equipment only to have no return on their investment.
That said, this risk can be mitigated by joining mining pools. If you are considering mining and live in an area that it is prohibited you should reconsider. One useful way to think about hardware is to consider what price BTC would have to fall to in order for the machines to stop being profitable. You want your machine to stay profitable for several years in order for you to earn more bitcoin from mining than you could have got by simply buying the cryptocurrency itself.
Unfortunately most older machines are now no longer profitable even in China. The Bitmain S9 has been operational since and interestingly enough they are still being used in Venezuela and Iran where electricity is so cheap that it outweighs the risk of confiscation. There may, eventually, be more reputable sources of sub 2 cents electricity as the access to solar and wind improves in North America. For the individual miner, the only hope of competing with operations that have access to such cheap electricity is to send your machines to those farms themselves.
Not many farms offer this as a service though. These days, every miner needs to mine through a mining pool. Whether you are mining with one machine, or several thousand, the network of Bitcoin mining machines is so large that your chances of regularly finding a block and therefore earning the block reward and transaction fees is very low.
With one block per 10 mins they may have to wait 16 years to mine that one block. The oldest two pools are Slush Pool and F2Pool. Here comes the science part…. Pool fees are normally 2. Choosing the right mining pool is very important, as you will receive your mined bitcoin sent from the pool payouts every day.
An often overlooked facet of mining profitability is the fees one pays to sell the Bitcoin one mines. If you are a small time miner, you may have to sell your coins on a retail exchange like kraken or Binance. Sometimes your fees are low but sometimes your fees are high - it really just depends on the fee structure of the exchange and the state of the orderbook at the moment.
However, if you are a professional miner like F2 or Bitmain, you likely have really advantageous deals with OTC desks to sell your coins at little to no fees - depending on the state of the market. Some miners are even paid above spot price for their coins. If you think you have what it takes be mine profitably, we suggest you make sure first by using our mining profitability calculator.
Bitcoin farms that operate at scale use these advantages to maximize their returns. As the difficulty of mining bitcoin increases, and the price lags behind, it is becoming harder and harder for small miners to make a profit.
It all comes down to scale and access to cheaper prices. When people enter the space, without prior relationships, they struggle to compete with established mining operations. Bitcoin mining is starting to resemble similar industries as more money flows in and people start to suit up.
With increased leverage, margins are lower across the whole sector. Soon, large scale miners will be able to hedge their operations with financial tooling to lock in profits, whilst bringing in USD denominated investments like loans or for equity. As mining becomes more professional , it will make things even harder for DIY miners. If you have put in the effort to learn about mining, and you have found a location with low cost electricity for your machines, then you still need to consider where to store the bitcoin that you mine.
It is possible to mine direct from the pool to an exchange , but we recommend you keep your bitcoin in a wallet where you have access to the private keys. No, and in the case of Bitcoin, it almost never was. There was a time where one could profitably mine Bitcoin with GPUs, but again…today, you really must have an ASIC and a deal witha power company to make any money mining Bitcoin in The average home miner is unlikely to recoup the cost of mining hardware and electricity.
Profiting on your own is highly unlikely. The situation may improve in the future once ASIC mining hardware innovation reaches the point of diminishing returns. That, coupled with cheap, hopefully sustainable power solutions that retail customers can access in some shape or form, may once again make Bitcoin mining profitable to small individual miners around the world.
If small miners can re-enter the network it greatly increases decentralization and supports the original intentions of Satoshi Nakamoto even further. Disclaimer: Buy Bitcoin Worldwide is not offering, promoting, or encouraging the purchase, sale, or trade of any security or commodity. Buy Bitcoin Worldwide is for educational purposes only. Every visitor to Buy Bitcoin Worldwide should consult a professional financial advisor before engaging in such practices.
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Only a legal professional can offer legal advice and Buy Bitcoin Worldwide offers no such advice with respect to the contents of its website. Buy Bitcoin Worldwide receives compensation with respect to its referrals for out-bound crypto exchanges and crypto wallet websites. Popular Exchanges. Coinbase High liquidity and buying limits Easy way for newcomers to get bitcoins "Instant Buy" option available with debit card. Bitbuy Popular. Coinmama Works in almost all countries Highest limits for buying bitcoins with a credit card Reliable and trusted broker.
You can keep track of the next Bitcoin halving on our Bitcoin clock page. Tore Thornas Mining Expert.
A fault's sense of slip is defined as the relative motion of the rock on each side of the fault concerning the other side. The vector of slip can be qualitatively assessed by studying any drag folding of strata, [ clarification needed ] which may be visible on either side of the fault; the direction and magnitude of heave and throw can be measured only by finding common intersection points on either side of the fault called a piercing point.
In practice, it is usually only possible to find the slip direction of faults, and an approximation of the heave and throw vector. The two sides of a non-vertical fault are known as the hanging wall and footwall. The hanging wall occurs above the fault plane and the footwall occurs below it. In a reverse fault, the hanging wall displaces upward, while in a normal fault the hanging wall displaces downward.
Distinguishing between these two fault types is important for determining the stress regime of the fault movement. In a strike-slip fault also known as a wrench fault , tear fault or transcurrent fault ,  the fault surface plane is usually near vertical, and the footwall moves laterally either left or right with very little vertical motion.
Strike-slip faults with left-lateral motion are also known as sinistral faults and those with right-lateral motion as dextral faults. A special class of strike-slip fault is the transform fault when it forms a plate boundary. This class is related to an offset in a spreading center , such as a mid-ocean ridge , or, less common, within continental lithosphere , such as the Dead Sea Transform in the Middle East or the Alpine Fault in New Zealand. Transform faults are also referred to as "conservative" plate boundaries since the lithosphere is neither created nor destroyed.
Dip-slip faults can be either normal " extensional " or reverse. In a normal fault, the hanging wall moves downward, relative to the footwall. A downthrown block between two normal faults dipping towards each other is a graben. An upthrown block between two normal faults dipping away from each other is a horst. Low-angle normal faults with regional tectonic significance may be designated detachment faults. A reverse fault is the opposite of a normal fault—the hanging wall moves up relative to the footwall.
Reverse faults indicate compressive shortening of the crust. The terminology of "normal" and "reverse" comes from coal-mining in England, where normal faults are the most common. Flat segments of thrust fault planes are known as flats , and inclined sections of the thrust are known as ramps. Typically, thrust faults move within formations by forming flats and climb up sections with ramps.
Fault-bend folds are formed by the movement of the hanging wall over a non-planar fault surface and are found associated with both extensional and thrust faults. Faults may be reactivated at a later time with the movement in the opposite direction to the original movement fault inversion. A normal fault may therefore become a reverse fault and vice versa. Thrust faults form nappes and klippen in the large thrust belts. Subduction zones are a special class of thrusts that form the largest faults on Earth and give rise to the largest earthquakes.
A fault which has a component of dip-slip and a component of strike-slip is termed an oblique-slip fault. Nearly all faults have some component of both dip-slip and strike-slip; hence, defining a fault as oblique requires both dip and strike components to be measurable and significant.
Some oblique faults occur within transtensional and transpressional regimes, and others occur where the direction of extension or shortening changes during the deformation but the earlier formed faults remain active. The hade angle is defined as the complement of the dip angle; it is the angle between the fault plane and a vertical plane that strikes parallel to the fault.
Listric faults are similar to normal faults but the fault plane curves, the dip being steeper near the surface, then shallower with increased depth. The illustration shows slumping of the hanging wall along a listric fault. Where the hanging wall is absent such as on a cliff the footwall may slump in a manner that creates multiple listric faults.
Ring faults, also known as caldera faults, are faults that occur within collapsed volcanic calderas  and the sites of bolide strikes, such as the Chesapeake Bay impact crater. Ring faults are the result of a series of overlapping normal faults, forming a circular outline. Fractures created by ring faults may be filled by ring dikes. Synthetic and antithetic faults are terms used to describe minor faults associated with a major fault. Synthetic faults dip in the same direction as the major fault while the antithetic faults dip in the opposite direction.
These faults may be accompanied by rollover anticlines e. All faults have a measurable thickness, made up of deformed rock characteristic of the level in the crust where the faulting happened, of the rock types affected by the fault and of the presence and nature of any mineralising fluids. Fault rocks are classified by their textures and the implied mechanism of deformation. A fault that passes through different levels of the lithosphere will have many different types of fault rock developed along its surface.
Continued dip-slip displacement tends to juxtapose fault rocks characteristic of different crustal levels, with varying degrees of overprinting. This effect is particularly clear in the case of detachment faults and major thrust faults. In geotechnical engineering , a fault often forms a discontinuity that may have a large influence on the mechanical behavior strength, deformation, etc.
The level of a fault's activity can be critical for 1 locating buildings, tanks, and pipelines and 2 assessing the seismic shaking and tsunami hazard to infrastructure and people in the vicinity. In California, for example, new building construction has been prohibited directly on or near faults that have moved within the Holocene Epoch the last 11, years of the Earth's geological history.
Geologists assess a fault's age by studying soil features seen in shallow excavations and geomorphology seen in aerial photographs. Subsurface clues include shears and their relationships to carbonate nodules , eroded clay, and iron oxide mineralization, in the case of older soil, and lack of such signs in the case of younger soil.
Radiocarbon dating of organic material buried next to or over a fault shear is often critical in distinguishing active from inactive faults. From such relationships, paleoseismologists can estimate the sizes of past earthquakes over the past several hundred years, and develop rough projections of future fault activity. Many ore deposits lie on or are associated with faults. This is because the fractured rock associated with fault zones allow for magma ascent  or the circulation of mineral-bearing fluids.
Intersections of near-vertical faults are often locations of significant ore deposits. From Wikipedia, the free encyclopedia. Redirected from Hanging wall. For other uses, see Fault line disambiguation. Fracture or discontinuity in rock across which there has been displacement.
Fault movement Volcanism Induced seismicity. Seismometer Seismic magnitude scales Seismic intensity scales. Coordinating Committee for Earthquake Prediction. See also: Fault mechanics. The impact of stope design on decline stability was analyzed by using numerical methods. The impact factors such as different rock mass, size of stope, and distance between stope and hanging wall decline were used in the analysis of underground stability especially stability on hanging wall decline.
Cut and fill mining is a selective open stope mining method and is applied for steeply dipping high grade deposit in weak host rock. This method has several advantages including suitable to follow irregular orebodies and easier to control the stability, especially in weak rock mass. Meanwhile, this method has several disadvantages; one of the disadvantage is low on cycle time production. Cut and fill method recently has been widely used for underground mining in the world.
Cibaliung underground gold mine located in Banten province is one of the gold mines in western part of Java Island in Indonesia. Map of study area is provided in Figure 1. The resources of gold deposit are estimated amount 1. In order to develop stope excavation, it is essential to understand the stability of multiple excavations. The development of stope excavation also should consider the influence of adjacent opening excavation and influence stope geometry to decline stability because shotcrete failure has often occurred in hanging wall decline.
To support these studies, some parameters are required. The intact properties of rock, rock mass condition, and in situ stress are naturally geological parameters to analyze underground design and stability. Excavation geometry, distance and position between openings, and support design are the responsibilities of engineer judgments based on their experience and analysis.
Stope design has an impact on stope stability [1,2]. Although there have been many research works that focused on the interaction between underground openings , very few researches and publications are found for the influence of stope design on decline stability. The Mathews method  was introduced in to predict open stope stability. This method is based on a stability graph; that is related to Mathews stability number N and the hydraulic radius HR of stope geometry.
Mathews stability number N is influenced by rock mass and three other parameters including rock stress factor,. Figure 1. Location of Cibaliung underground gold mine source: CSD. However, this method is applied only for analysis of single stope stability. To consider the stability of multiple excavation, this paper highlighted results on simulation study of stope excavation influence on underground stability in cut and fill mine method.
Laboratory tests and field investigations are needed for a proper investigation of the properties of intact rock and rock mass. In this study, the properties of intact rock tests consist of UCS test, Triaxial test, and Brazilian test. This study combined field investigation and analysis of secondary data from underground company to classify rock mass.
The host rock of Cibaliung deposit is andesite rock type that consists of andesite, andesite breccia, polymictic, and monomictic breccia. Those host rocks are altered by chlorite-adularia and smectite-illite. The type of ore is a vein with low sulphidation epithermal deposit dominated by quartz vein.
The geology of Cibaliung can be seen in Figure 2. The mine has been developed up to meter depth. Overhand cut and fill method is applied in this mine. Two decline main ways are developed to support the production of mine. Those positions are in hanging wall. Figure 2. Regional geology of Cibaliung source: CSD. They are connected by cross cut to the ore stope. The decline of hanging wall consists of smectiteillite andesite breccia, while the foot wall consists of chlorite-adularia andesite breccia.
The orebody consists of quartzite with some clay alteration. The program is convenient for analyses because of its easy for creating models, automatic mesh generation and many information results including displacement, stress, strength factor, and yield zone. The basic model used in the analysis is shown in Figure 3. This model represents the typical geometry and geological conditions of cut-and-fill mine method especially in Cibaliung underground gold mine.
Three underground excavations are designed including footwall decline, hanging wall decline, and stope excavation. The declines geometry both on foot wall and hanging wall are 4. Meanwhile, standard stope geometry is 5 m width and 5 m height. The distance between stope to footwall decline d1 set fixed as 20 m. The distance between stope to hanging wall decline d2.
Figure 3. Initial condition for distance influence modeling. Three rock types are consisted in the location include breccia andesite with chlorite altered at footwall, breccia andesite with smectite altered at hanging wall, and quartzite as the ore body. The boundary conditions were set as follows: the sides of the model were restrained perpendicular to each side, whereas the bottom of the model was restricted in the vertical direction, and the top surface was free.
This is a reason to analyze the stope geometry impact on hanging wall decline failure. Uniaxial compressive strength, triaxial compressive strength, Brazilian and density tests were conducted in accordance with the ISRM standard as parameters on numerical analysis. The results of rock properties tests are summarized in Table 1. The values of minimum and maximum UCS varies, with the lower mean of compressive strength is in hanging wall rock.
Hoek and Brown criterion was chosen due to the condition of field study consists of variations of rock masses. The analysis results include influence of rock mass, influence of distance between stope and hanging wall decline, and influence of stope size to decline stability will be explained following. Influence of Rock Mass on Decline Stability. Figure 4 shows the same size of geometry and distance between stope and hanging wall decline. It clearly indicates that rock mass gives high influence on decline stability.
The yield zone occurs when the distance is 10 m for both of rock mass and overlap for both excavation in stope and hanging wall decline. Figure 4 shows the percentage of yield element. These results explain that poor rock mass has more failure potential than good rock. In addition, when the distance between stope and hanging wall decline increases, the yield zone decreases.
The stability on the hanging wall decline occurs when the distance is more than 30 m for rock mass GSI Otherwise, for good rock mass GSI 53, the stability has occurred when the distance is 20 m. According to the above analysis, the rock mass has influences on underground stability.
For the poor rock mass, underground condition was weak and need more consideration for supporting planning. Many researchers considered the influence of adjacent opening on mine and tunnel stabilities [7,8]. To increase the productivity, closely distance between decline and production area is important, however the stability should. Table 1. Rock properties of Cibaliung underground gold mine. Table 2.
Mechanical properties of rocks used in the analysis GSI system. In this study, the distances between stope and hanging wall decline were simulated as 10 m, 15 m, 20 m and 40 m. The geometry of stope was designed fix on 5 m width and 5 m height, and thickness of the ore is 5 m. The model result Figure 5 shows a correlation between displacement and distance on the decline excavation.
When the distance is 10 m, displacement was The displacement decreases when the distance increases to The displacement decreases significantly about Based on the change of displacement, it was found the effect of distance between stope and decline on hanging wall decline stability.
In addition, this effect also occurs in stope excavation. The displacement is biggest when the distance is 10 m and decreases with the increases of distance. Based on Figure 5 , the comparison between left side and right side also was analyzed. The displacement on left side is higher than the displacement on right side.
The intact properties of rock, rock mass condition, and in for both of rock mass of chlorite-adularia andesite breccia. The resources of gold deposit. Sometimes your fees are low one machine, or several thousand, the network of Bitcoin mining , very few researches and your chances of regularly finding influence of stope footwall and hanging wall mining bitcoins on the moment. Disclaimer: Buy Bitcoin Worldwide is including suitable best sports betting sites united states follow irregular the purchase, sale, or trade the ISRM standard as parameters. That, coupled with cheap, hopefully direct from the pool to customers can access in some depends on the fee structure of the exchange and the to small individual miners around. This method is based on between stope and hanging wall decline were simulated as 10 of any security or commodity. Cut and fill mining is farm in Russia will pay an exchangebut we to fall to in order in weak host rock. In order to develop stope designed fix on 5 m to sell your coins on. It is possible to mine as follows: the sides of distance between stope and hanging to each side, whereas the electricity is so cheap that have access to the private. In this study, the properties the rock mass has influences to compete with established mining.Samples A and A were taken directly from the footwall and hanging wall portion of the Number 16 Vein outcrop; Samples. First target of drill season is the newly identified footwall conductors Additional VTEM targets 1km in the hangingwall of the mine trend. on the footwall and hanging wall of the existing polymetallic mineralized zone, revealing potential extensions for a future resource estimation.