JOHANNESBURG (miningweekly.com) − Aim-listed Paragon Diamonds said the first results from the bulk sampling programme at its Lemphane kimberlite project, in Lesotho, has revealed the recovery of the site’s first large diamonds.
The company completed the processing of the first bulk sample that comprised 2 385 dry tons of volcaniclastic kimberlite taken from its 84%-owned Lemphane kimberlite pipe.
A total of 46.79 ct in 102 diamonds were recovered, at a recovered grade of 1.96 carats per hundred tons and at an average stone size of 0.46 ct.
The high number of larger diamonds sparked particular interest, Paragon stated, with 14 diamonds weighing over one carat and five diamonds weighing over two carats. The largest diamonds ranged from 6.30 ct to 2 ct.
"Recovering five significant diamonds at such an early stage from such a relatively small sample is a positive start for the Lemphane project. The proximity to Mothae and Letšeng, known for being two of the world's most important sources of large diamond gemstones, would indicate that we are certainly in the right place," Paragon chairperson Francesco Scolaro added.
The company reported that the diamond population was heavily skewed towards the larger diamond sizes, with 62% of the total carats being present in diamonds of one carat or larger and 39% in diamonds of two carats or larger.
A preliminary observation from Paragon's independent consultants, MSA Group, was that about 85% of the diamonds were white and clear dodecahedra, with the remainder showing attractive brown and yellow colours and some macle shapes. Stone size, quality and colour were highly encouraging, the consultancy stated.
The company further stated that the results at Lemphane were significant, as they correlated closely with the results seen at other prominent Lesotho kimberlites that were at the same exploration-development stage.
"We have confidence that we will be recovering greater numbers and larger diamonds in the near future. With a potentially coarse diamond size distribution established, completion of the sampling should help secure Lemphane's position as a world-class Lesotho kimberlite," commented Paragon MD Stephen Grimmer.
The infrequent presence of larger diamonds and relatively small sample sizes at the start of a sampling programme typically leads to an initial underestimation of grade and average stone size. Therefore, a further 32 000 t of sample material has been extracted from the Lemphane kimberlite and tested as part of the bulk sampling programme, Paragon said.
With the processing of increased tonnages of samples taken from across the entire kimberlite, Paragon anticipated higher statistical confidence and improved grades, stone sizes and a higher incidence of larger diamonds.
The results do not yet include diamonds from tailings recrush/retreatment, which will be recovered at the end of the programme.