vtsnowedin wrote:A couple of points. Some rocks get broken down to sand ,others become clay. It is a matter of grain size. When it comes to defining sand, it is the particles that fit through a quarter inch screen and won't go through a #200 screen. A #200 screen has 200 fine wires per inch each way and the holes between the wires measure just .0029 inches or .07366 millimeters.
What falls or can be washed through those small holes is silt or clay and interferes with the cements (of whatever type) ability to bond the stones /gravel and sand together. A specification sand for concrete or asphalt paving will have five percent or less passing the #200.
What is retained on the quarter inch screen is stone and that maybe gravel stone polished round by water or crushed rock with sharp fractured faces. High strength concrete or pavements use crushed rock or crushed gravel stone as the fractured faces increase the ultimate yield strength of the product.
You can make sand by crushing rock fine enough but you have to screen out or wash out stone dust finer the #200 and in most locations natural sand deposits are still cheaper.
Hot mix pavements today often use recycled pavement that has been ground off the old road or crushed excavated pavement , and that can be half of the new mix with only a very small amount of new sand added along with enough new crushed stone and liquid asphalt cement to get to the desired proportions.
Most of your concrete mixes vary around 50% stone 50% sand plus or minus ten percent each way. The cements today often have a high portion of fly ash in them and along with chemical additives called super plasticizers and have obtained strengths and work-ability unimaginable when I started in the industry in 1975.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Tanada wrote:
So question definitely sand related, if I were to buy some bulk fill sand what screened size would you recommend? I had some trees removed and as the unground portions of the stump have decayed I now have a couple craters in my yard I need to peel the sod off of, fill and replace the sod. I took care of one last year with bag sand, but it was the hole from a relatively small tree, the remaining locations need around a yard of fill dirt each.
It is the economic and cultural toll of sand mining that has finally persuaded the city to address the issue. This summer, sand was imported to a handful of Asilah’s beaches in an attempt to make them more accommodating and presentable for the tourist season. The measure, however, is only a temporary fix to a larger problem.
'It has always been about money, and that won’t ever change'
Subjectivist wrote:Stumbled over the just now, seems like this issue is more severe than I had realized.
http://www.middleeasteye.net/in-depth/f ... -475164766It is the economic and cultural toll of sand mining that has finally persuaded the city to address the issue. This summer, sand was imported to a handful of Asilah’s beaches in an attempt to make them more accommodating and presentable for the tourist season. The measure, however, is only a temporary fix to a larger problem.
'It has always been about money, and that won’t ever change'
vtsnowedin wrote:Subjectivist wrote:Stumbled over the just now, seems like this issue is more severe than I had realized.
http://www.middleeasteye.net/in-depth/f ... -475164766It is the economic and cultural toll of sand mining that has finally persuaded the city to address the issue. This summer, sand was imported to a handful of Asilah’s beaches in an attempt to make them more accommodating and presentable for the tourist season. The measure, however, is only a temporary fix to a larger problem.
'It has always been about money, and that won’t ever change'
I have to wonder what they are using for the stone component of the concrete and how the seawater contamination of beach sand effects the structural strength of the finished project.
Just one earthquake away from a disaster?
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
ROCKMAN wrote:Boys - "...sand was imported to a handful of Asilah’s beaches in an attempt to make them more accommodating and presentable for the tourist season." I think y'all missed the point. They don't have a sand problem per se. The problem is the long shore current washing the beach away. IOW they are trying to maintain a beach where Mother Earth doesn't want a f*cking beach. LOL.
“The Price of Sand” is a documentary about the frac sand mining boom in Minnesota and Wisconsin. Due to a rapid increase in demand, pure silica sand has become a valuable commodity, and mines are opening here at a rapid rate.
The silica used in hydraulic fracturing (aka : “fracking”), has other uses– glass manufacturing and toothpaste, for instance — and a few established mines have been in operation here for decades. But now, new companies have arrived, and land with accessible silica deposits is selling for high prices.
In addition to a bonanza for a few lucky landowners, the new mines promise jobs and economic stimulus for the small towns and rural areas nearby.
The Film
In 2010, an oil company bought a tract of land in near my mother’s house, in rural Goodhue County, Minnesota. The prospect of an open pit mine led to the formation of an opposition group, a series of public meetings, and a temporary county moratorium on frac sand mining.
I’m a filmmaker, so I visited people who live near existing mines and interviewed them. They told me stories–intense truck traffic, plummeting property values, toxic silica dust–a catalog of complaints that surprised me with its variety and intensity. I made clips from the interviews and posted them on YouTube.
YouTube shorts can provoke discussion (56,000 views so far), but the story of this mining boom is more complex. Good people are on both sides of the issue, and sometimes the facts aren’t obvious. “The Price of Sand” is a 1-hour documentary film that grew out of my short YouTube video project–more extensive, with new stories–a more comprehensive look at what’s happening.
UPDATE 2016
We’re working on a follow-up. The film will be a short, under 30 minutes in length. This time around, I have a partner, Producer Wendy Johnson. There’s more information on our Facebook page: The Price of Sand
The goal of this project: find the real price of frac sand. Not just in dollars, but in friendships, communities and the future of our region.
Jim Tittle • St. Paul, MN • director
Watch it on Amazon Prime: THE PRICE OF SAND
In the dead of night we've come to film a mafia at work.
We know the dangers. We've been told our lives could be at risk.
But this is the vision we must have to expose an extensive network of underworld criminals, known as the "sand mafia", which is destroying beaches and riverbeds across India.
Foreign Correspondent travelled to the drought-stricken Bundelkhand region in central India to film them at work, stealing sand — a resource that's now so valuable it's been dubbed "India's gold".
Sand is vital for India's booming construction industry, which is tipped be in the top three in the world in less than a decade. It employs over 35 million people and is valued at well over $126 billion per annum.
It's hard to move unnoticed through the primitive surrounding villages. As a foreign crew, we really stand out, but an element of surprise is vital for what we want to do. We retreat to a safe house, and wait for the go-ahead.
Hours later as an evening quiet descends across the hills, we hear the tractors moving in to a nearby river bed. That's our cue to move too.
It's pitch black as we drive closer on a sandy, windy path. We're whispering, we're unsure.
Before we know it we see what we've come for. We scramble out of the vehicle and film as a tractor-load of sand drives past us. It's sand mafia men with their booty.
We need to get closer, but with sand everywhere we risk our car being bogged. We can't be left without a way to quickly escape. So we begin to walk in on foot. But as we approach we notice a shadow ahead. There is someone there — and it's too dangerous for us to keep going.
We've blown our cover now and the remaining tractors begin to leave at speed. One almost rolls over, careering around the bend as it tries to escape our camera.
It's time for us to go too, but the sand mafia want to make sure we won't come back. So they send an escort — a couple of men on a motorbike. They follow us for a while, but when they're sure we are heading out of the area, they take off and we manage to leave safely.
Deadly and corrupt — India's 'largest scam ever'
The people at the heart of these illegal sand-mining operations can be incredibly dangerous, and will stop at nothing to get their hands on this valuable and diminishing resource.
Those who've tried to stop it have been beaten, maimed and in some cases murdered — accidental activists whose lives have been turned upside down by these criminals.
In the satellite city of Noida on New Delhi's outskirts, Akaash Chauhan is fighting for justice. His father, 52-year-old Paleram Chauhan, was shot dead as he fought to save communal village land from being completely stripped of sand.
"When I reached the hospital and I saw my father's dead body, I have never been able to forget that sight. Even today, it flashes in front of me," Akaash says.
"My father's fight has become my fight.
"Sand mining is ongoing — my father was against it, I am against it and so is my family."
Sumaira Abdulali, a genteel unassuming woman, is one of India's foremost campaigners against illegal sand mining and the sand mafia.
She spends much of her time travelling around the country gathering data on how much illegal sand mining is taking place and how much money it generates. In the process she has been insulted and threatened.
Her public profile gives her a degree of protection now, but in the early days of her activism she was beaten and hospitalised when she tried to save Kihim beach, near Mumbai, from being stripped bare by sand gangs.
"It's probably the largest scam ever in our country," she says.
Powerful politicians and their business allies stand accused of allowing the illegal trade to thrive in return for generous financial kickbacks. But riverways and beaches are being destroyed — their eco-systems changed forever.
Foreign Correspondent also succeeds in capturing an illegal sand tractor operating in broad daylight. The workers shovel sand into the tractors by hand. They're from the lower rungs of the black market trade.
"I feel bad that I do this job but there's no other work I can do," the tractor driver said after being blocked by our car.
"I get a little extra money that is why I do it. Everybody does what they do for their stomachs."
Illegal sand mining is the dirty secret at the heart of India's booming economy. Conservatively worth $250 million a year, there's little political appetite to stop it.
The theft of sand occurs in a range of ways, from high tech dredging, to digging with bare hands, to free-diving.
On Mumbai's Thane river, local fishermen plunge to depths of 40 to 50 feet to gather sand from the riverbed.
With no safety apparatus and up to two minutes of air in their lungs, they fill a tin bucket with black muddy sand. It's an illegal act, but we have convinced them to allow us to film.
Incredibly, the men are often drunk. It's the only way they can calm their nerves to succeed in filling the bucket up to 200 times a day.
Sumaira Abdulali regards these men as victims of the sand mafia, not criminals.
She is full of praise for her fellow activists because she knows they are mostly isolated and must act alone without the protection of the media spotlight, putting themselves and their families at risk.
"I think their bravery is really astounding," she says.
"Unlike me, they have no real way of reaching out and telling their stories when they start. So they must feel so strongly about the issues and their lands."
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Sand, spanning miles of beaches, carpeting vast oceans and deserts, is a visual metaphor for limitless resources. Yet researchers in this week's journal Science seize another metaphor - sand in an hourglass, marking time running out.
Sand is the literal foundation of urban development across the globe, a key ingredient of concrete, asphalt, glass, and electronics. It is cheap and easily extracted. Scientists in the United States and Germany say that easy access has bred a careless understanding of the true global costs of sand mining and consumption.
Sand mining across the world is being linked to coastal erosion, habitat destruction and the spread of invasive species. Standing pools of water created by sand mining become breeding sites for malaria-carrying mosquitoes. The negative consequences of mining are not felt at the point of consumption, but rather in poorer regions where sand is mined. Tempting profits from large-scale sand trade spawns organized crime and international conflict. There are indications that attempts at regulation have inspired more illegal and unscrupulous profiteering.
The biggest worry, the authors say, is that the true impact and economics of sand mining isn't even clearly understood. The simple anecdotes which have received some publicity make it clear solutions can't be delivered to only one spot. The transactions of sand, and the toll of obtaining the natural resource, span the globe in a web of supply, demand and power.
"As with many natural resources the world depends upon, sand is a perfect example of transactions that seem simple, but in reality, are deeply complex and rife with inequity and risk," said co-author Jianguo "Jack" Liu, Michigan State University's Rachel Carson Chair in Sustainability and director of the Center for Systems Integration and Sustainability. "A system approach is needed to avert disasters and achieve sand sustainability."
Sand and gravel are the world's most extracted resource, and like water, sand falls into a category of a "common-pool" resource, meaning it is easy to get, and difficult to regulate. But while some sources of sand replenish themselves, the paper's authors note that the current combination of skyrocketing demand and unfettered mining to meet that demand is a recipe for shortages.
"Sand becoming a scarce resource is a key emerging issue for the global environment and society, but not yet fully recognized or understood," said first author Aurora Torres, a research fellow at the German Centre for Integrative Biodiversity Research (iDiv) and the Martin Luther University Halle-Wittenberg. "Classifying suitable sand as abundant or renewable is not the right way to proceed unless replenishment rates match or exceed extraction rates. Unfortunately, the global sand budget is still missing. Until now, research on sand issues has been largely fragmented and has mostly followed conventional disciplinary lines."
The authors, who also include Jodi Brandt at Boise State University and Kristen Lear at the University of Georgia, point out that what is most certain is the glaring uncertainty of the global sand supply and the true costs of obtaining sand. "A looming tragedy of the sand commons" threads sand extraction through Earth's key environmental and sustainability issues - transportation, trade and the possibility of harm to both people and nature. The group is launching the first international effort to systemically examine the scope of sand supply and demand.
Sand's big picture needs scrutinizing, they say. Understanding what happens at the places sand is mined, the places sand is used and the many points in between which experience loss, benefits or harm is within reach using research frameworks like telecoupling - which allows researchers to understand socioeconomic and environmental interactions over distances.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Return to Environment, Weather & Climate
Users browsing this forum: No registered users and 17 guests