Simple Active Cyanidation Plant

This is a proposal only. We have not yet built this system. We are submitting it to get feedback and suggestions from people before we do build it. If there is an organization that would like to help fund this we would be happy to talk with them. A conventional CIP system consists of several large tanks with agitators and air pumps. The ore slurry consists of finely ground ore, cyanide solution and carbon. Our proposed system has several key areas that differ from a CIP system. These are: 1. The agitation of the ore/cyanide slurry is done in a rotating drum mixer. Specifically, this is a concrete mixing unit that is normally mounted on a Redimix delivery truck. This mixes and aerates the slurry using a single motor. These units are available in most countries, either new or used. 2. The flow of the slurry and leachate through the system is by gravity. The gold producing area in Masara, Kenya is rolling hills so this system uses the natural slopes to operate. 3. The carbon is placed in a separate, secured chamber and the pregnant leachate passes through it by gravity feed. The leachate can be tested before and after it goes through the carbon chamber to determine how the system is working. This eliminates the need for a mechanism to separate the carbon from the slurry. 4. The leachate is separated from the ore using a simple gravity filter. The filter can be fabricated locally from steel. It is intended to hold a complete load from the mixer. It consists of a main tank to hold the slurry/tailings and a second tank below the main tank to hold the leachate. The leachate flow to the carbon chamber is controlled by a valve to provide a steady feed into the carbon chamber. Using a gravity filter to separate the tailings from the leachate is slower than a mechanical system. However, our experience with tank leaching is that this should be effective on a 24 hour cycle. 5. The tailings are removed from the filter manually. This is normal in this area and the costs for this are low. For example, a 75 tonne tank costs 3,000 ksh (about US$25 to empty or fill.) This can be mechanized if the operator feels it is economically advantageous. 6. The system has only two mechanical/electrical units. These are the motor turning the mixer and a small pump lifting the cyanide solution to the elevated leach tank. A conveyor belt to lift the ore into the rotating drum may be added as well which would add one more motor. All of these motors could be electric or diesel depending on the availability of electrical power. 7. The Carbon chamber and in-ground leachate tank, are constructed using locally made bricks and plaster. This is the local standard for constructing these at tank leaching operations in the area. 8. This system can be “twinned” with an existing leach tank operation to use the same carbon chamber, in-ground leachate tank, leachate pump and elevated leachate tank. This can reduce the capital cost significantly. OPERATION It is intended that the plant will operate on a 24 hour turnaround. We anticipate that the operation will require 3 or 4 people to operate it. This will be a technician / operator and 2 or 3 laborers to shovel ore and tailings. It is anticipated that it will operate as follows: 1. A premeasured amount of ore and cyanide leachate is loaded into the mixer. The leachate is gravity loaded from the elevated tank via a metering valve. The finely ground ore is either loaded by hand or by conveyor belt. 2. The mixer is run for a predetermined period of time. This will need to be determined experimentally and will depend on the type of ore etc. 3. The mixer is reversed. This will eject the slurry from the mixer into the chute so it flows into the filter. 4. The slurry sits in the filter and the cyanide solution runs out into the catchment tank below the filter. A flow valve controls the flow into the carbon chamber so that the leachate runs at a controlled rate. 5. After the flow of leachate ceases (probably overnight), the tailings are manually removed from the filter and dumped at the tailing site. 6. The leachate with the gold removed runs to the in-ground leachate tank. It is then pumped to the elevated tank for the next batch. 7. When the carbon is fully loaded with gold as determined by testing, it is removed to elution. The timing of this will depend on the size of the carbon chamber, the amount of ore processed and the concentration of gold in the ore. BUDGET We are still developing the capital budget for this system. Our target is to have the capital cost under US$30,000. CONTACT For more information, please contact Peter Lattey at peter@peterlattey.com or on Whatsapp at +1 310-968-3252.

Simple Active Cyanidation Plant - Technology Assessment

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Categories	Sub-categories	Assessment questions	Assessment
Properties of the ore	Type of deposits	Is the technology suitable for hard rock deposits?	None
		Is the technology suitable for alluvial gold deposits?	None
		Is the technology suitable for eluvial gold deposits?	None
	Type of ore	Is the technology suitable for free milling ores?	None
		Is the technology suitable for oxide ores?	None
		Is the technology suitable for sulphide ores?	None
		Is the technology suitable for carbonaceous ores?	None
		Is the technology suitable for refractory ores?	None
		Is the technology suitable for sand rock bearing ore?	None
		Is the technology suitable for ore with clay material?	None
		Is the technology suitable for ore bearing nuggets?	None
		Is the technology suitable for ore in desert areas?	None
		Is the technology suitable for ore in wet conditions?	None
		Is the technology suitable for ore in coarse gravels?	None
		Is the technology suitable for ore in fine gravels?	None
	Grade/gold content	Is the technology suitable for high grade ores?	None
		Is the technology suitable for low grade ores?	None
	Grain size of the gold)	Is the technology suitable for fine grained gold?	None
		Is the technology suitable for course grained gold?	None
		Is the technology suitable for mixed fine and course material?	None
		Is the technology suitable for very/ultra fine grained gold?	None
	Feed volume (batch volume)	Is the technology suitable for large quantity of feed material?	None
		Is the technology suitable for small quantity of feed material?	None
Operationals requirements	Cost of equipment	Are the costs of procuring the technology affordable to artisanal miners?	None
		Are the costs of procuring the technology affordable to small-scale miners?	None
		Are the costs of operating the technology affordable to artisanal miners?	None
		Are the costs of operating the technology affordable to small-scale miners?	None
		Are the costs of maintanance and replacement affordable to small-scale miners?	None
		Are the costs of maintanance and replacement affordable to artisanal miners?	None
	Utilities and inputs required	Does the technology require water?	None
		Is the amount of water required suitable to processing by individual miners?	None
		Does the technology require electricity or power source?	Yes
		Is the amount of electricity required suitable to processing by individual miners?	None
		Does the technology requre diesel?	No
		Is the amount of diesel required suitable to processing by individual miners?	None
		Does the technology require reagents during processing?	None
		Is the amount of reagents suitable for processing by individual miners?	None
		Does the technology require any other infrastructure?	None
	Type of organisation	Does the technology allow operation by individual miners?	None
		Does the technology allow operation by group of miners?	None
		Does the technology allow operation by organisations?	None
		Does the technology allow operation by processing plants?	None
		Does the technology work only with a continous system?	None
		Does the technology work with batch and continous systems?	None
		Does the technology work only with a batch system?	None
Processing flowsheet and performance of the techology	Processing flow	Does the technology work as a standalone?	None
		Does the technology work as part of a process system?	None
	Gold recovery	Does the technology offer high recovery rates compared to the amalgamation process?	Yes
		What are the typical gold recoveries for this technology?	None
		Does the technology produce gold directly?	None
		Does the technology produce gold directly but in a different form to be converted to gold?	None
		Does the technology require other processes to recover the gold?	None
		Are there potential gold losses during processing with this technology?	None
	Processing time	Does the technology offer less processing time compared to the amalgation process?	None
	Tailings	Can the technology re-process tailings?	None
	Recovery of other minerals	Can the technology recover other minerals in addition to gold?	None
	Visual tracking and monitoring	Does the technology allow visual tracking and/or monitoring?	None
Local considerations	Availability of the equipment	Does the technology make use of equipment that is locally available?	None
	Availability of the inputs	Does the technology require inputs that can be locally sourced?	None
	Scalability of the technology	Can the technology be scaled up or down to suit the spectrum of ASGM activities?	None
	Adaptability of the technology	Can the technology be used in remote areas?	None
	Ease of use/learning (skills requirement)	Is the technology easy to use or learn?	None
		Does the technology require knowledge /skills on metallurgy to use?	None
	Capacity to maintain	Is the technology easy to maintain?	None
Health, safety and environment Risks	Health and safety hazards	Does the recovery of gold using this technology pose any health and safety hazards?	Yes
	Environmental risks	Does the recovery of gold using this technology pose any environmental risks?	Yes