Niewejaarskraal Project

Niewejaarskraal Property Location

Background

The Niewejaarskraal Project is located on the south bank of the Orange River in the Herbert district of the Northern Cape Province, some 57km southwest of Douglas. It is a past producer that was acquired by Rockwell in 2009 and held on care and maintenance until 2013 when it was returned to productive status. Niewejaarskraal has a mine life exceeding 10 years based on current resources.

Rockwell plans to carry out substantial work to refine the geological model at Niewejaarskraal which will inform a new mine plan. In order to complete this, the Company suspended activities on the Niewejaarskraal property in April 2015. The suspension is not expected to have a material negative impact on the financial results as Niewejaarskraal is currently incurring operating losses.

Geology

Three gravel types have been identified on the property. A BIF rich, BIF poor and Massive gravel have been observed on Terrace A. The difference lies in the BIF content, sand content and clasts size to distinguish the Massive and the BIF rich/poor gravels. The BIF rich gravel has a BIF content of between 50% and 70% while the BIF percentage is less in the BIF poor and the Massive gravel. The gravels are poorly sorted in an open to composite framework. The BIF rich gravel has coarser basal gravel. The Massive gravel has a high percentage of cobbles to boulders. The matrix of the gravel is of calcretized sand and in some areas grits is observed. The BIF poor gravel is finer (pebble-cobble dominated) and highly interbedded by sand lenses with thin gravel packages. The BIF rich gravel has an increased diamond grade and value compared to the BIF poor and Massive gravel. All of the units are overlain by a thin, calcretised package of sandy, zeolite-rich, matrix-supported Orange River influence gravel.

Processing Plant

The Niewejaarskraal processing plant has a throughput capacity of 100,000m3 per month. The plant has two processing streams, namely a dense media separation stream that processes the fine gravels with flowsort X-ray machines and a Bulk X-ray to process the coarse gravels.

Ore preparation Ore Enrichment Final/Recon recovery machines
Grizzly Screen De-sanding Screen Scrubber DMS BV Bulk Sorters Flow Sort Machine VE Recovery Machine
1x450tph 1x300tph 1 x 150tph 1x50tph 1x70tph 4x (5tph total) 1x500kg/h

Mining

Mining at Niewejaarskraal is on a contract mining basis. CML Operations is Rockwell’s contract mining partner for this operation. The type of gravel being mined dictates the machinery used and manner which the gravels will be excavated. The Rooikoppie gravels that cap the packages are mined by means of; excavator that loads the fairly loose gravels onto articulated dump trucks and then transported to the plant. The palaeo gravels have a silcreted cap, the degree of hardness dictates if blasting will be required. At Niewejaarskraal, preparation of mining block is carried out by blasting the hard silcreted top. The calcrete cap is drilled and loaded with explosives with the depth and spacings of the holes being dependent on the thickness of the calcrete. Once the silcreted top has been blasted, a bulldozer is used to strip the over lying calcrete; this kind of stripping is possible due to roll over mining that allows for concurrent rehabilitation. At Niewejaarskraal, stripping of the blasted calcrete is loaded onto articulated dump trucks by excavator and transported to rehabilitation area. Once the stripping has been completed mining commences with creation of a slope on current mining block; mining of gravel is always at an angle to allow for the mixing of the low grade middlings with the higher grade basals as well as to allow for liberation due to rolling action of the gravels down the mining slope. When sufficient liberation has been achieved gravels are loaded by means of excavators onto articulated dump trucks and transported to the processing plants. Tailings are transported back to the current mining areas after processing, using articulated dump trucks. A tyre dozer or bulldozer is used to flatten these rehabilitation areas.

Download the Technical Reports

Screen Shot 2015-06-04 at 3.06.04 PM
Niewejaarskraal Resource Summary June 2015

Screen Shot 2015-06-04 at 3.05.32 PM
Technical Report on the Niewejaarskraal Alluvial Diamond Project