Startup and Shutdown Procedure -Merrill Crowe
In Preparation for Startup, the following items must be checked before the equipment in the filtration circuit is started. Check that the filters, repulpers, filtrate pumps, vacuum pumps, flotation blower, and transfer pumps are ready to run. Check that the cooling water compressant system is functional. The selected cooling water filter must be clean, and reclaim water must […]
Merrill Crowe Slurry Filtration Circuit Post-Agitated Leach
The object of the post agitated leach drum filtration circuit is to recover as much of the dissolved gold and silver as possible. The efficiency of recovery can be increased significantly by utilizing two successive stages of filtration such as the two stage system applied in this plant. Recovery of the precious metals is also improved […]
Agitated Leaching Circuit Operation
Ground slurry from the trash screen enters this EXAMPLE Agitated Leach circuit at a rate of 35.5 cubic meters per hour, and 45% solids. The slurry passes through each of the four tanks, and should remain in each tank for a period of approximately 12 hours. Each tank is 8 meters in diameter by 8.5 […]
Dissolve Gold and Silver with Cyanide
The addition of gold or silver to an alkaline sodium cyanide solution will cause the gold and silver to react with the cyanide and dissolve into the solution in a process called cyanidation. This process is more frequently referred to as leaching. As well as reacting with the precious metals, the cyanide will react with […]
Thickener Startup & Shutdown Procedure
An EXAMPLE Startup of the thickener may occur under two sets of very different circumstances: After a major plant shutdown or the initial plant start-up, when the thickener is completely empty OR/AND After a shutdown whereby the thickener has been left full of pulp, and rakes and underflow pumps have been inoperative (such as after a […]
Mill Feed Thickener Operating Principles
Under normal conditions our EXAMPLE mill feed thickener rake drive will operate with the gear mechanism lowered, regardless of grinding or leaching operations. Operating lights on the mill control panel indicate whether the rakes are fully lifted, fully lowered, moving up or down, turning or stopped. An exact intermediate rake position is not indicated on […]
Grinding Circuit Startup and Shutdown Procedure
Grinding and Classification Circuit
Our EXAMPLE Grinding and Classification Circuit is designed to grind 500 tonnes of ore per day, operating 24 hours per day, with an availability of 95%. This circuit will grind -5/8″ material from the Crushing Plant, classify the slurry in one of two cyclones, and pass 70% of the minus 200 mesh material to the […]
Calculating DWi from Axb Drop Weight Test Results
The drop weight test is a common laboratory measurement used to determine the comminution characteristics of rock samples. A common metric derived from a drop weight test is a value “A×b”. Another common metric that is derived from the SMC Test™ variant of a drop weight test is a “Drop Weight Index”, abbreviated as DWi. […]
Why Oxygen is Important in Cyanidation
The Rule and Function of Oxygen in Cyanidation.—Oxygen appears to be an indispensable factor, either directly or indirectly, in the dissolution of gold and silver by cyanide solutions, except in the case of the haloid compounds of silver. Whether the action of oxygen in the dissolution of gold be a direct one, as illustrated by the […]