Marietta, GA – The business built from the ambitions of a young Portuguese immigrant is celebrating 20 years in operation. Joe Dos Santos, the Founder and President of Dos Santos International, was brought to the land of opportunity in 1959. He dreamed of starting a family company. That dream became a reality on July 7, 1997 when he started DSI.
Not our world famous DSI Snake Sandwich High Angle Conveyor, but an overland conveyor this time. I’ll just go ahead and cut to the chase. Diamonds got me last time. So what goes best with diamonds? Well of course the precious metals that holds those gorgeous stones. The stuff that’s going to diversify your portfolio because it’s worth so much now. That’s right…GOLD!
So here’s what’s been going on. Dos Santos International is currently finishing up the Los Filos Project that was awarded in cooperation with M3 Engineering of Tuscon, AZ. Goldcorp’s Los Filos Project is in the Nukay mining district of central Guerrero State in southern Mexico. It promises to be one of the largest open-pit mines in the country. It reminds me of our diamond mine project in Canada. Those systems are contributing to projects that are projected to overtake South Africa as the new primary source of diamonds for the world. See, we like to do things bigger and better around here!
Originally, there was a system that conveyed the ore from the crushing plant to the leach pads via a glory hole ore pass and an underground conveyor, through the hill. An agglomeration drum mixed in the agglomerate before final delivery to the leach pads. The system experienced material flow problems right from the start, especially during heavy rains. The sticky ore tended to plug up the ore pass. Geological instability ultimately collapsed the ore pass, putting the transport system out of service after only four months of operation.
So to keep it worth its weight, Goldcorp had to find another alternate to truck haulage which is way too expensive. That’s when they asked M3 Engineering to develop an alternate conveying route. M3 put their trust in DSI and we figured out the most logical, most direct and of course economical path. Instead of going under that hill, we planned to go right over it because….well…frankly…WE CAN! That path required a down-hill high angle conveyor. We called it the DSI G.P.S. (Gently Pressed Sandwich) High Angle Conveyor. We were ready in March 2009 to proceed, but wouldn’t you know it…the instability on that hill wouldn’t allow it. Back to the drawing board!
This time a conventional conveyor system was developed, following the already developed truck ramps. DSI expertise proved particularly advantageous on this project. The original ten-conveyor-flight system was rationalized to only seven flights by amalgamating with horizontal curves. The third conveyor flight is specially engineered to accomplish the agglomeration by mixing through five intermediate tripped transfers. This route agglomeration, conceived by Goldcorp, resulted in substantial savings by eliminating the need for the additional agglomerating drum.
The overland conveying path is mostly downhill. While this presents the normal controlled starting and stopping problems, it also creates great savings opportunities. The downhill flights are decisively regenerative. Also, the drive motors, now generators, will feed power back into the grid which can be used to power other mine equipment. These carefully engineered conveyors will be equipped with variable frequency drives to ensure operations at maximum efficiency (by pryor). There we go being “green” again!
So my interests have gone from diamonds to gold and Dos Santos International continues to hold my attention into 2010. Can’t wait to see what they do next!
If you want more technical information on this project, visit our NEWLY UPDATED web site at www.dossantosintl.com.
I am happy to submit a guest blog for Joe Dos Santos. This is to lighten things up from the technical stuff engineers like so well and frankly…I just don’t understand. Until now!
Spending most of my college life in public relations and marketing classes, engineers and engineering seemed a world away…even though I could walk to the engineering building on my campus in under five minutes. That’s actually strolling. Still, the dynamics of what they did, the math, the figures, the equations! It was way over my head. After all, it was all I could do to get through my remedial math courses much less pursue a higher level of math. Now don’t think I didn’t feel the pressure. My father, a Cornell graduate said he learned to love the thing that really challenged him. Yep….math! And of course, we can’t forget my brother the MIT graduate. Of course I felt the pressure. After all…they are both…you guessed it, Engineers!!!
Well after being with our family company, Dos Santos International, in a full time, official capacity for a year now, I’m going to let my dad and brother in on a little secret. I’m intrigued! I’ve finally found my niche in engineering! I can make it simple…one word! No need for equations or protractors! DIAMONDS!!! That’s right. Diamonds…you know the phrase…a girl’s best friend. Well this girl has finally found a lot of interest in the math behind this sparkling, much sought after wonder! See, it turns out, it takes engineering (math and science…UGH!) to get these dazzling beauties to a jeweler near you. I’m proud to say, that Dos Santos International is responsible for helping to bring these gems to the surface and through the separation process. See, we just completed two projects in Canada. These mines, along with others in the planning process, may soon propel Canada to the number one position in diamond production.
Now not only did that catch my eye because of what is being unearthed, but also because of the high-tech DSI Snake Sandwich Belt Conveyor…wait make that two DSI Snakes. Snap Lake incorporates two, each elevating at the building’s opposite ends… but there’s more. This project, from the beginning, was intended to be environmentally friendly as well. The area where these diamonds are being mined is frozen solid throughout much of the year. I mean the conditions are pretty harsh. Because of this, the project would have to be under cover. No, not secretive but enclosed and heated so people aren’t freezing to death. Sure I’d stand out in freezing temperatures for just a chip of that gorgeous rock, but there are others to consider. Still, they had to make sure they could contain this whole project in a small space (by brandon). That’s where our Snake Conveyors came in. Because of our high angle capability and our system’s gentle yet firm hugging of the kimberlite (diamond ore) in the sandwich between the belts, we are able to bring these beauties up safely without using too much of Canada’s precious land. Because of our Snakes, the process building’s foot print is small, minimizing the environmental impact and reducing both capital and operating costs, especially the cost of heating. The project maintains the land around it without disturbing much of Mother Nature, while at the same time, unearthing one of nature’s most beautiful treasures. Conveyors…well they’re not the most beautiful sight to me but let’s face it. Diamonds look good on everyone…or anything!
For those of you, who enjoy the math and understand the equations, please visit dosssantosintl.com for the logistics of these systems. We have a detailed list of our installations. For the rest of you, just remember DSI Snake Sandwich Belt Conveyors. They are now this girl’s best friend.
Through study analysis and experience the writer will attempt to continuously rationalize and expand the conventional conveyor technology revealing the link between theory and practical issues and in the process, through a deeper understanding, take the technology beyond its presently perceived limits. This approach has, in the past 20 years, yielded a greater understanding, a broader application of the principles, and even new technologies to the market place.
Experiences/Frustrations with Conveyor Belt Specs:
Why don’t Belt Manufacturers understand what they publish?
At Dos Santos International we are experts in the Sandwich Belt High-Angle Conveyor Technology. The Sandwich belt system works on the principle of hugging bulk material continuously in a sandwich between two smooth surfaced rubber belts. Hugging pressure on the bulk material develops its internal friction, which resists any back sliding tendencies, allowing the material to convey at any high angle up to vertical. The writer rationalized this technology as an expansion of the conventional conveyor technology during the period 1979 thru 1982. This work culminated in the landmark article “The Evolution of Sandwich Belt High-Angle Conveyors” by Dos Santos and Frizzell.
All Dos Santos Sandwich Belt Conveyors start with a troughed bottom belt that receives the bulk material load in a conventional manner. The bottom belt is joined by a top belt which sandwiches the bulk material between. The belt sandwich is then supported along a convex curve of inverted troughing idlers along which the conveying angle is increased up to the ultimate high angle. In the case of the DSI Snake Sandwich System, shown on Figure 1, the profile is made up of alternating convex curves where the inner belt is supported on the convex curve of troughing idlers and the outer belt hugs itself and the conveyed material up against the inner belt according to the relation:
Pr = T/R,
where Pr is a radial load, T is the belt tension and R is the radius of curvature.
A moment is induced at the troughed belt section according to the equation:
M = EI/R,
where M is the moment on the troughed belt section, E is the elastic modulus of the belt in the warp direction, I is the belt section moment of inertia.
Belt stress due to the induced moment is:
Fb = My/I = Ey/R,
where y is the distance from the troughed belt section’s neutral axis.
Since a conveyor belt cannot be subjected to compression, as it will buckle, at a minimum the belt tension must counter the compressive bending stresses, at the inside of the curve. Furthermore, when the belt tension is added to the tensile bending stresses, at the outside of the curve, the combined stress must not exceed the belt’s tension rating.
So, the induced bending stresses are directly related to the belt’s elastic modulus. The lower the elastic modulus the lower the induced bending stresses, permitting tighter convex curves and a more compact transition from the low (conventional) loading angle to the ultimate high angle. Nylon warp fabric belting offers the best solution for tight convex curves.
Indeed, these curvature constraints apply to all convex curves along the DSI Snake Sandwich conveyors. These curvature constraints also apply to convex curves along conventional conveyors though in this case there is typically no great incentive to make such curves tight.
The curvature constraint equations for troughed belt conveyors, based on the basic equations above, are published in the engineering manuals of all major belt manufacturers. The all important Belt (elastic) Modulus is determined for the belt’s long term behavior according to the ISO 9856 Belt Modulus test.
Because of its importance, Dos Santos International always strictly specifies the belt modulus (not to exceed) value. Such specified values are typically comfortably above those already published by the belt manufacturers.
In this light it is frustrating to find, after its manufacture, that the belting we ordered exceeds the specified belt modulus and even more frustrating when the manufacturer claims that they guarantee its performance. Indeed performance is guaranteed to fail in such a case unless measures are taken to compensate for the higher modulus, such as increasing tension to offset the higher induced compressive bending stresses. Higher tension however, may not be possible if such, when combined with the already higher tensile bending stresses, exceed the belt’s tension rating. Indeed DSI design criteria attempts to allow ample margin in case of such mishaps which occur all too often.
Such a mishap, recently, is the source of my frustration and prompted this writing