Dear Editor,
I read with a deep sense of concern, in your edition of January 18, a statement, supposedly emanating from the Minister of Natural Resources in the article entitled ‘Bauxite output strong but industry battling depressed global prices, high costs.’ I said, concern, since I am under the impression that the people advising the Minister would have taken the trouble to understand some of the basics surrounding bauxite production in Guyana. There is no 1:1 ratio between crude bauxite ore and the finished product at any stage of the industry. This applies to both Bosai and Rusal though, in the case of Bosai, it is of greater significance due to the production of RASC and AGB.
The article shows Bosai producing, between January and November 2015, the following mix of products;
- RASC 122.219 tons
- AGB 24,154 tons
- Calcined Grade Bauxite 76,247 tons
- Cement Grade Bauxite 92.276 tons
- MA Z 5,892 tons
- Total 320,788 tons
The article then goes on to make the categorical statement that the company mined 320,788 tons of bauxite ore, creating the impression of a 1:1ratio between mined ore and finished products.
While I have a problem with the nomenclature of some of the products and am not sure if the figure for mined ore refers to wet or dry tons, my concern is with the impression being given to the nation and the world that a company could mine 320.788 tons of bauxite ore and produce a mix of products totalling exactly 320,788 tons – an exact one to one conversion. My understanding is that Bosai has been able to improve some of the recoveries, but it is difficult to envisage them achieving the levels suggested.
The production of RASC, for instance involves:
- washing of the mined ore, to reduce free silica levels
- calcination which involves driving out between 30 and 32% combined water
- Dust losses during the calcination process
Under Demba and Guymine, the losses at these three stages resulted in a 20-25% recovery, ie, 4-5 tons bauxite ore for the production of 1 ton finished product. My understanding is that Bosai has improved on the washing and dust losses; there is, however, nothing they could do about the calcination loss (assuming, of course, that they are still producing what is universally accepted as RASC). Under that scenario, I assume they may be able to improve the recovery to around 30% ie 3.33 tons ore to 1 ton RASC which would require 403 322 tons ore to produce 122,219 tons RASC.
I assume that the product classified as AGB is Abrasive Grade Bauxite, which, like RASC goes through the same calcination process except that the losses through washing and calcination may be lower, resulting in approximately 2.5 tons ore to 1 ton finished product, requiring 60,385 ore for the production of 24,154 tons finished product.
Where the other products are concerned, a total of 174,415 tons, I assume these are all dried products. Bauxite ore comes out of the ground with an average of 15% free moisture. While some customers could accept wet bauxite, most customers, because of handling and freight considerations, demand bauxite dried to between 5 and 7% moisture. The free moisture loss, together with dust loss during the drying process, result in losses of 10-15%. Assuming Bosai is able to reduce these losses to the median 12.5% – a 87.5% recovery – they would need a minimum of 193,330 tons ore to produce 174, 415 tons dried products.
While I concede that some of my conversions are based on assumptions, Bosai would have needed approximately 663.000 tons ore, more than double the quantity indicated, to produce the product mix indicated. I must also confess that they could have produced the full mix of products with only 320, 788 tons mined ore by utilizing stockpiled material – tailings, for instance – which they may not classify as mined ore, but the 1:1 ratio between the reported mined ore and finished products creates an element of suspicion.
Yours faithfully,
Sylvester Carmichael
