Gold Project
The company has initiated the production of gold by gravity separation. The
mine is Located at Bondo -Kwaluala village, Handeni district in
Tanga
Region, about 36km from Handeni town in the Tanga Region of Northeast Tanzania and 287km from Dar es Salaam city in Tanzania.
ML No. 00858 & 00856
Area of Project : 20.00 sq. km ( 5000 Acre)
Phase I : Gravity separation by Trommel
Dharti has implemented gravity separation using a trommel for processing alluvial gold, which is an effective method for extracting free gold from sand, gravel, or river deposits. This process involves several key steps:
- Washing away mud and clay
- Screening out large stones using the trommel
- Concentrating gold particles using centrifugal concentrators, shaking tables, and gold carpets
The trommel screen plays a crucial role in this process by efficiently separating materials based on size while washing the ore1. It provides a simple, efficient, and economical solution for upgrading a wide range of material and optimizing subsequent process steps10.
Trommel screens for gold mining are designed to be hard-wearing, high-impact, and abrasion-resistant2. They can handle feed rates up to 5,000 m³/hr and are particularly effective for alluvial gold mining operations8.
Phase II: Chemical Gold Processing Technology
Dharti is planning to install a Carbon in Leaching (CIL) plant for processing oxide-type gold ores, especially when recovery rates from flotation or gravity circuits are not satisfactory. The CIL process combines leaching and adsorption steps, offering several advantages over other methods23.
Carbon in Leaching (CIL) Process
The CIL process involves the following steps:- Thickening: Slurry containing uncovered gold is pumped to a thickener to adjust density.
- Leaching: The thickened slurry is pumped to leaching tanks where gold is dissolved in an aerated sodium cyanide solution.
- Adsorption: Dissolved gold is simultaneously adsorbed onto coarse granules of activated carbon.
- Recovery: Gold-loaded carbon is separated and processed to recover the precious metal24.
CIL is particularly effective for processing oxide ores and can achieve gold recovery rates of up to 99%24.
Carbon in Pulp (CIP) Process
While Dharti is planning for CIL, it's worth noting the similar Carbon in Pulp (CIP) process:- Leaching: Gold ore is first leached in cyanide solution without carbon present.
- Adsorption: The gold-bearing solution is then brought into contact with activated carbon in separate adsorption tanks.
- Carbon separation: Gold-loaded carbon is screened from the slurry and sent for elution and regeneration