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#caving

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'Feasibility study and optimal #Coal drawing process for fully mechanized #Caving in close-distance extra-thick coal seams' - a #Research article in the Journal of #MineAutomation on #ScienceOpen: scienceopen.com/document?vid=b

ScienceOpenFeasibility study and optimal coal drawing process for fully mechanized caving in close-distance extra-thick coal seams<p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" dir="auto" id="d107733e122">Research on optimal coal drawing parameters for working faces with significant variation in seam thickness, where the thickness exceeds the standard mining height in close-distance coal seams, has been limited. This study focused on the feasibility and optimal coal drawing process for fully mechanized caving in the 011N1 <sup>-1</sup> working face of the Xilutian Coal Mine, Pingzhuang Coal Industry (Group) Co., Ltd., Inner Mongolia. First, theoretical analysis determined that the maximum damage depth of the floor caused by mining in the overlying 021N2 working face was 3.88 m, which was less than the distance between the 011N1 <sup>-1</sup> and 021N2 working faces. This finding confirmed the feasibility of fully mechanized caving for the underlying 011N1 <sup>-1</sup> working face. Subsequently, using a combination of theoretical analysis and field measurements, the study employed a fuzzy mathematics method to quantify the effects of uniaxial compressive strength, seam burial depth, seam thickness, coal fracture development, roof grade, and interlayer gangue thickness on the caving characteristics of the top coal. Membership function evaluation indicated that the top coal caving tendency of the 011N1 <sup>-1</sup> working face were at a moderate level. Finally, a coal drawing numerical model was established using the PFC 2D discrete element particle flow software to analyze the effects of different cutting-to-drawing ratios and coal drawing methods on the recovery rate of the top coal. The results revealed that, when the seam thickness exceeded the standard mining height, setting the cutting-to-drawing ratio to 1:4.5 effectively accommodated thickness variations with minimal impact on top coal recovery. Moreover, a three-cycle coal drawing process significantly improved the recovery rate. Field observations demonstrated that, after optimizing the coal drawing process, increasing the instantaneous cutting-to-drawing ratio with seam thickness better adapted to geological conditions and significantly enhanced top coal recovery in the working face. </p><p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="first" dir="auto" id="d107733e137"> <b>摘要</b>:目前针对近距离煤层厚度变化范围较大、煤层厚度超出正常开采高度的工作面的合理放煤工艺参数研 究较少。以内蒙古平庄煤业(集团)有限责任公司西露天煤矿011N1 <sup>-1</sup>工作面为研究对象,开展了近距离特厚煤 层综放开采可行性及合理放煤工艺研究。首先,通过理论分析计算出近距离特厚煤层上方021N2工作面开采后 底板最大破坏深度为3.88 m,小于011N1 <sup>-1</sup>工作面与 021N2 工作面之间的距离,表明对下煤层011N1 <sup>-1</sup>工作面进 行综放开采是可行的。然后,结合理论分析与现场实测,采用模糊数学方法量化了煤体单轴抗压强度、煤层埋深、 煤层厚度、煤体裂隙发育程度、顶板级别及煤层夹矸厚度对顶煤冒放性的影响,基于隶属度函数评定 011N1- <sup>1</sup>工 作面顶煤冒放性为中等水平。最后,基于 PFC 2D 离散元颗粒流软件建立了放煤数值模型,分析了不同采放比和 放煤方式对顶煤采出率的影响,发现当煤层厚度超过正常开采高度时,将工作面采放比定为 1:4.5 可有效适应煤 层厚度变化,此时对顶煤采出率的影响较小,且采用三轮放煤工艺可有效提高顶煤采出率。现场放煤效果表明, 优化放煤工艺后,随着煤层厚度的增大,增大采放比能够较好地适应地质条件变化,显著提高工作面顶煤采出量。 </p>

For everyone in the world outside the US starting up the isolation process...remember how well that worked in the 1930's. It left tens of millions to die, turning back refugees sent them to their deaths, and fascism still came for their countries anyway. Isolation & abandonment is not a great policy. The world is even more globalized now than it was 100 years ago. The faster we realize we can rise or fall together, the better off everyone will be.

Politics can be complicated, but empathy is not. Empathy demands that we look at what is going on in all oppressed nations and peoples, and bear witness. And no one with empathy can then refuse to help. This is why empathy is being made to be the enemy. This is why individualism is being touted.

So. Let's all climb out of this pit now, and together, as the people of the Earth.

#cave#caves#caving

There is a cave which (was) accessed through a pipe culvert. Due to housing development, it is no longer there. It was a historic record site for cave crayfish and I think cave fish as well. The directions to where the culvert intercepts the cave are accurate, but the bottom of the pipe turns to stone, and it appears the cave was filled in.

This is obviously a horrible idea for many reasons - the selfish reason being "your house may literally cave in" as chucking limestone rock into a solution cave that is carving out limestone is obviously not going to work. In the nearby city there is a law against filling a cave because they learned quickly this is horrible structurally. But this is the county where no such regulations exist.

A classic example of how it may sound good in theory to have fewer regulations and oversight so you can "get shit done easier", but the reality is, regulations are there so you don't fuck shit up. Of course, if one also just ignores rules & regs and does whatever they want to whomever they want, we have a different kind of problem. :blobthinking:

I think I am going to get some stickers made. IYKYK. Don't spoil it in comments. Any interest? I'm trying to determine if I need to do a really low volume or if I should just go for 50 or something. I'd ask for $2-$3 which should cover cost + mailing. Vinyl, quality, 3" circle. Pls comment if interested so I have a decent way to get an idea of interest. Thanks!

#art#design#cave

Keep fighting for the Earth, it is our only home.

Caves are a space highly at risk, and many species in them can be "canaries in the coal mine". The water in them tells the tale of the surface above: pollution, fertilizer, pesticides, microplastics, and more. Too bad wealth doesn't trickle down like pollution into ecosystems. We should really swap those two...

Today went out to an Alabama cave preserve my husband manages and put up some new signs at the parking area then hiked around to look at the cave entrances. One entrance with a waterfall was really nice. There's a 400+ foot pit not too far inside. We ran into some guys who had just rappelled to the bottom and climbed back up. #Caving #Hiking

GIS Corps Is Looking To Help Phreatic With Remote Spatial Volunteers
--
phreatic.org/ <-- shared home page
--
giscorps.org/become-a-voluntee <-- shared link to volunteer with GIS Corps
--
[want to be a part of some super interesting (remote) GIS volunteer work?!]
#GIS #spatial #mapping #volunteer #phreatic #explore #protect #seacaves #Sardinia #cave #caving #Phreatic #GISCorps #Italy #Supramonte #GulfofOrosei #model #3dmapping #environmental #speleology #hypogene #groundwater #waterresources #marine #marinecaves #coast #coastal
@GISCorps @Phreatic

A year ago this week I was with a team conducting research in the Scărişoara Ice Cave, #romania. This spectacular place contains #ice dating back more than 10,000 years! This unique archive holds valuable information about past #climate variability in this region. Some of the interesting work that has been done in this cave is reported here: nature.com/articles/s41598-017 Photo by M. Blatnik. #caves #caving #geology #earthscience #environment

Happy Valentine's Day from a gypsum heart in a cave.

Speaking of hearts, let's have some Real Talk! About hearts! Today I re-certified in CPR & First Aid. Did you know that socialized as female folk are far more likely to die from a heart attack / cardiac event than men? It's true! A large cause of this is due to the fact that symptoms are often not as-seen-on-TV; instead being brushed off as nausea, acid reflux, or indigestion. And what do we do when we feel ick? We go to the bathroom. So when we collapse, no one is around to see, much less administer CPR. So: check on your friends who disappear to the bathroom for a long time!

Sadly, there is also a huge disparity between races in survival as well. Not only does lack of medical access and environment & social factors mean there is higher risk (systematic racism), but overt racism also prevents bystanders from stepping in to help. Black & Latinx people suffer the most. (newsroom.heart.org/news/cardio)

CPR is not that difficult! It is more the mental challenge of being prepared to step in and help. If you can't get to a class (hands on with the training manikins is certainly recommended if you can!) still learn about it. All 50 states have Good Samaritan laws.

I personally know two people who are alive thanks to a normal everyday person knowing CPR, and intervening. This is community building, y'all! Take care of each other out there.

Some additional tips:
1. If someone has a medical emergency and you end up leading the way, always point and directly tell people what to do (ex: you in the blue shirt *pointing at them* call 911). If you just shout things, people will not jump into action. Be specific & direct.

2. Always check for a pulse on the same side you are kneeling on, you don't want to reach across their neck.

3. If there are enough people, direct folk not involved in helping to form a circle looking *out*. This gives some privacy, very important in these days of cell phone cameras and the fact that say, once the AED shows up, their chest will be made bare. Help protect the patient's privacy!

4. Good Samaritan laws generally have caveats such as never accept anything as a thank you (not even flowers, *nothing*) and stay with the person until someone of equal or greater training arrives. So if you say, start CPR then just get tired and stop with no one equal or higher taking over, then you are liable.

#heart#love#valentine
Replied to Sunguramy :nb_lily:

@sunguramy This is brilliant, as usual.

On a tangent: I've done most of my caving in the UK and France, and the scene is about 100% white (including me). I don't know if this is just a reflection of the demographics of the local (rural) area where the caves are or what. I have no idea how things look like at the uni / big city clubs.

Black Adventure Crew goes caving! Good start for #BlackHistoryMonth - making new memories :)

I approached this group about caving what now feels like a lifetime ago...an outdoor group focused on getting Black and Brown people outside into nature. They were interested in trying it, and now they do trips every year.

While it sucks that DEI is getting canned federally and in some states (why trying to equally include everyone is a bad thing I'll never understand), that doesn't mean we as individuals can't pick up the slack. There are so many stories from folk who say their white friends just never ask them to join for xyz activity...so check yourself. Ask your friends to join you. If you don't have diverse friendships, ask yourself why that is. Then go forth and foster community!

#caves#cave#caving