Hydroponics: The practical construction of a system to dispose of cyanide solution.

[SaltwaterServr]

Small deposit miners are at a disadvantage in many ways to junior and large mining companies on many different fronts. The biggest is our limited capital and their advantage of economies of scale.

They used cyanide leaching for exceptionally high recovery rates. We can do the same. The problem is they have a few extra hundred thousand or million lying around to set up processing of waste effluent. We don't have that. Well, if you do, I'm open for adoption.

Really, cyanide leaching of gold and then precipitation of the gold out of solution is a pretty easy process. The thing I'm going to deal with here is an inexpensive solution to the problem of having to dispose of cyanide and also the practical aspects of getting the EPA off our collective backs.

This entire system can be built with materials from Lowes/Home Depot, a hydroponics store online, and an aquarium store online. Simple, easy and I'll show you exactly how I've built several hydroponics systems in the past for fruits and vegetables. This will probably be broken up into different posts so it won't be one huge thing.

First we need a quick understanding of hydroponics. No, it's not for growing weed.

Hydroponics is growing plants where the nutrients to the plants are delivered in a pre-mixed solution rather than coming from in the ground. The plants are grown in a variety of inert (unreactive and nutrientless) substrates.

Hydroponics is a lot more costly than traditional farming/gardening since you're doing more than sticking a seed in the ground and watering when it doesn't rain.

The payoff though worth the time and money. First is that plants can be spaced much more densely, the only limitation you have is how much sun you can get to them. Second, plants grow 2-3 times as fast in a hydroponics set up because they aren't burning energy to try and pull nutrients out of the ground. Third, which isn't really important for us, is that you get 3-4x the amount of production from the plants as a traditional in-ground planting. Also, the plants don't have to fight through soil.

Traditionally in soil you have corn plants at a maximum density of one plant every 8 inches between plants and 20" between rows. In my 3rd generation hydroponic system I grew 5 plants per five gallon bucket and realistically those buckets can be touching each other by row and column. To put it another way, where you can grow a maximum of 21 corn plants in a 4'x4' area, I'm well over 60 plants. And I'm getting three crops to your one.

Soil production gets 21 ears of corn, I get 180+. That production is really going to help us out in getting rid of cyanide.

Here's some photos.

This is a low density first generation system I built. 3 plants per bucket, 27 plants total on a 4x4 palet.



An overall view of the kind of density you can plant for a full garden. When it was the end of the season, my okra, which aren't yet planted, were about 5' over the edge of the roof. Cut them down because we were worried about damaging the shingles in a wind storm.



Next up, I'll do a little more show and tell on what you need to get a hydro system running.

 

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[Mad Machinist]

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[SaltwaterServr]

Now I focused on corn plants initially in the first post because our selected plant (so far) to dispose of cyanide is sorghum. Both are row crops that have a heavy vegetative stalk that grows to support a relatively small amount of useful grain. Most people grow tomatoes, bell peppers, cucumbers, hot peppers, squashes, and lettuces in hydroponic system because your paying for each parcel of nutrients you supply so you get way more bang for your buck with those.

I grew corn because someone online said you couldn't. I also love sweet corn. Same person said I couldn't grow potatoes in a hydro system. I grew the best tasting red skin potatoes any of my neighbors had ever had.

To the point, we only moderately care about about the final grain production. Our first and foremost concern is taking cyanide, HCN in solution, and busting apart that C and N to grow a plant. Once we get that carbon atom and nitrogen atom split apart, we win. Simple as that. If we can sell off the grain, use the stalks for animal feed, or get the environmentalists on our side, we're playing with house money at that point.

So then, what does it take to grow anything in a general hydroponic system? You need a reservoir for the nutrient solution, irrigation hoses and a pump to move the solution to the plants. You need something for the plants to grow in because the EPA and BLM will crap out Tiffany gold cufflinks if you tell them you'll be pouring cyanide on the ground. 5 gallon buckets are going to be the best for us. We need to create a drain for those buckets, something for them to sit on, and fill those buckets with something that won't decompose that the plant roots can hold onto. Beyond that, you need a simple pH test kit and a nutrient test meter.

Buy this test meter. Trust me on this, it's by far the best one out there and built tough. Corn grows best at 2.8 to 3.2 on the meter, but will love 3.6 too. That's all you really need to know other than keeping your pH about neutral.

https://www.amazon.com/Bluelab-Commercial-Truncheon-Nutrient-Meter/dp/B005DPCTHE

So let's look at my old systems so that you can see what works and what doesn't. Really, when you're done reading this, you should be able to build a system that can start processing cyanide in about 3 weeks from the day you put it together.

Let's look at an overview of my first system, but we'll focus on the corn plants in the foreground.

This was taken May 9th of 2013 I think. The corn seedlings were started indoors by putting them between two damp paper towels in a gallon ziploc bag on top of the refrigerator. You can also start them in dirt or the Scott's seedling starters you can get online or at Lowes/HD. Remember, everything in this entire system is easily accessible online or at a box store.

May 9th, low density planting system of corn on a 4x4 pallet. I used 2" PVC as a drain pipe that connected together and went into a Sterilite plastic box reservoir.



The white pellet looking stuff is known as perlite. You can get it at most feed stores. It's light, inert, doesn't break down. It's also really fond of percolating down into the drain system and plugging it up. Under about 3" of that perlite is lava rocks like you find at, you guessed it, Home Depot and Lowes. I'll abbreviate Lowes/Home Depot as LHD from here on out.



I found the next time around that using straight lava rocks works much better. Different year, different layout. Just showing you the rocks.



The 2" drain system also doesn't work. I went to a 4" sewer drain line that I cut 3" holes into. The buckets have a piece of 2" pipe capped with a coupling that acts as a drain from the bucket. It does leak on occasion, but I have a fix already in mind. No worries.



The black hoses are standard 1/2" irrigation line from LHD. The brown or black small lines are 1/4" irrigation line from LHD. Don't worry about the green round things on the end of those tubes, we won't be using them. They're really to regulate flow in a large system based on plant needs.



Reservoir and home built manifold system. We may need manifolds if you have multiple plant systems running that are on different inclines. Or you can use different pumps.



I DO NOT recommend using those lightweight containers as the reservoirs. The plastic cracks. You can see the different ones I used on my third system here. Really, I'd want to use the small heavy built black tubs you can get at LHD that have the yellow lids. You want to stay low profile because all of your solution had to drain back to the reservoirs. The taller the reservoir, the taller everything else has to be as well.

These also were linked together, but you can't tell. Both tanks have a 2x4 girdle built around them since the pressure of the water causes them to bow out.



What I think would work best for us is a purpose built water tank like these: Norwesco :: Above Ground Tanks :: Specialty Water Tanks

Not cheap, but they're perfect for what we want to do. Plus they're a helluva lot stronger than the one's I used that worked pretty good.

Next, the pump. Nothing special, a Rio 900 gph pump. I used this exact model. Never had a problem with it either, but it's always good practice to have an extra on hand.

https://www.amazon.com/gp/product/B0009YHRJY/ref=s9_acsd_hps_bw_c_x_6

 

[SaltwaterServr]

Here are some photos of expected growth rates of corn that come from my first system.

May 9th, 2013



May 18th, my notes say I was getting 3/8" to 3/4" of growth per day depending on the cloud cover.



May 23rd, You'll see some light yellow stripes. Added epsom salts in later years and fixed that. I built this rack out of 1/2" PVC to keep the plants upright. I simply added on to the legs as they got taller.





May 28th. Little higher on the rack. I used 3/4" nylon straps and clothes pins to keep the plants from rocking back and forth in the high winds we have in May in the DFW area. This first year I ran my entire system off of one set of reservoirs. The corn eats so much nutrients and needs it really high. I had to switch to isolating the lettuces, strawberries and a few other items into a different solution grade system. Notes from this day say that the plants were processing about .4 on the Truncheon of solution per day.







June 2nd.





June 7th. Not very tall due to edge of field effects. If you've driven by corn fields you'll notice that the edges of the fields always have the shortest plants. Corn and a few other row crops do not like wind. Stunts their growth like it did to my corn. We had a really windy year so that was part of the problem.

Ears already starting to grow. Keep in mind, this is less that one full month of growth from the first picture of the seedlings.





That's it for the photos of the corn growth. The next week I was getting married and going on my honeymoon. Once we got back I'm pretty sure that we had picked all the corn by July 4th.

Now look at that date again. Picked ears by July 4th. You saw the size of the plants on May the 9th. 2 months from seedlings to picked. A more dense system to alleviate edge of field effects would've had a little longer growth time, but still we're removing cyanide the entire time. Multiple crops per year.

A few photos of my second and third system.

four plants per bucket.



Five plants per bucket, and a guard cat.





Next we'll talk about problems with it.

 

[SaltwaterServr]

There are problems with a hydroponic system, namely, water leaks. That's a huge issue if you're working with cyanide. No bueno at all.

I have no photos of my fourth system I built here in Phoenix. It was a different type of system. All of the photos you've seen are what is called a nutrient-film technique. The solution is pumped for about 30 minutes every few hours and coats the roots and rocks with a nutrient film. The fourth version was adapted to the hotter climate so the plants all had their roots immersed in solution 24 hours a day with continual air supply to each container so the roots wouldn't "drown". That type of system will not work for us in this case. There's no way to support the plants fully as they grow. Best suited to bell peppers and such.

The biggest issue I faced is getting a proper seal on the 5 gallon buckets to their PVC drain pipes. I used PVC couplers inside the bucket with a piece of PVC pipe going through the bottom of the bucket and then siliconed the crap out of the seal. Worked pretty dang good. There were some small leaks.

The real issue is that even with a 2" PVC pipe, the roots will fill that hole and then you have overflows out of the top of the bucket. These roots aren't what you expect from corn either. They're not tap roots, they're more like fibrous mats. The plant doesn't need to send down large root systems to find the nutrients, so it doesn't. It grows what looks like a mop of roots and that's good enough for it.

Secondarily, I used milk crates to hold the buckets in a wood frame system. That doesn't work. A lot of the crates broke due to the weight of the plants in the second and third version.

Third, the reservoirs crack sometimes, but if you put them on a sand base they do a lot better because there are no voids causing stress in the plastic points. Still, I had cracks even in my fourth version.

So, how do we fix all of that?

I feel pretty confident that if we cut an 6-8" diameter hole out of the bottom of the five gallon bucket and put a piece of this fluorescent light grid material inside the bucket on top of the hole:



Now fill your buckets with the lava rock. I still like using that stuff because it can be recycled time and time again by burning the old roots out in a fire.

Then there will always be plenty of open area for the roots to grow through and it will never get 100% clogged. Where do you get the fluorescent light grid stuff? Home Depot and Lowes of course. Menards for y'all northern folks.

Now we got the buckets set for draining, but we're going to completely toss aside the way I drained the system with pipes as I did before. Instead, we're going to build a shower. Or rather, we're going to build a shower pan.

Start with this frame. The height will be determined by the height of the reservoirs we use for our cyanide solution. It also needs to be lower on one side than the other for drainage.



Now put a piece of good OSB or plywood on top. Frame the outside edges with 2x4's as well to create a pond effect. Like this. Sorry, best I could find on a quick notice.



Now line that with 40mil plastic shower pan liner from LHD/Menards. Get the 5' wide so there's extra to overlap the sides.

Line that "tray" table top with the plastic. Start at 4:10 in this video to see how to install a shower pan liner.



Now we'll have to put that drain somewhere on one side of our new "pond". The drain location should be set somewhere that it makes it convenient to plumb and drain into the cyanide reservoir. The location of that is specific to your location.

Next step. We need to set the buckets of sorghum on the surface of the shower pan liner, but give a gap so that the buckets can drain. Also, the spacers need to have no sharp edges so the liner isn't punctured. I'm thinking that you could cut 3" long pieces of 2" PVC pipe and use those as spacers. Stand the spacers on their ends (vertically) so the buckets don't roll. Put 4-6 of those spacers under each bucket. I would say to make sure they sit just inside the outer edge of the bottom of the bucket, or set the bucket's edge on those spacers.

Another option would be to use untreated 1x1s or 2x2s as spacers. Not sure if the wood would concentrate the cyanide, so I'm really leaning to going with stubs of PVC pipe or couplings. Cutting pipe is cheaper of course.

Now you can pack as many buckets on that table as need be for your system. Every single drain problem reduced to one single drain and plumbing system. Even if a bucket overflows, you'll catch all the solution and you're good to go.

I will say this. When you run your irrigation feed line into the bucket forest, make sure it loops up higher than the buckets so that the solution doesn't run back down it if there is a leak from your 1/4" feed lines.

When placing the buckets on the table, make sure you can reach into each one. It makes things easier if you need to stand a bucket upright that has fallen over for whatever reason. Also, if you build two tables, leave about 30" between each of them so you can walk between them. This makes sure you can get to any plant bucket on any table.

Really we'll need multiple tables since we'll have harvests of sorghum throughout the growing season. Once one is nearing maturity (note how fast that happened with my corn) you'll need to be bringing another table of seedlings on line.

If you have questions, let's fire away to work through any conceptual problems we might have.