Blina Diamond Project, Ellendale, Western Australia

Ellendale Diamond Project_Record2018/8_GeolSvyWA

For a Project overview watch our field video.

Figure 1:       Location

GIB Blina Diamond Project – Key Points

  • 100% GIB. Four granted mining leases with Native Title Mining Agreements
  • 40km strike of diamondiferous Terrace 5 alluvial gravels
  • Targeting high-grade alluvial trap sites using new Ground Penetrating Radar (GPR) bedrock mapping technology
  • Nine newly defined untested ‘high grade’ target areas (28 hectares), 2-8 metres deep
  • Historic grades from bulk sampling Channels 1 and 2 outside of the new target areas ranges from 4.0 cphm3 to 10.5cphm3
  • GIB Bulk sampling and trial mining in 2018 

8.43 carat Fancy Yellow diamond previously recovered from the Blina Project alluvials (GIB ground) during Terrace 5 sampling (Pit 82). This stone alone is valued at US$44,482.

1.0       Blina Diamond Project, WA                                                                     GIB 100%

The Blina Diamond Project in the Ellendale Diamond Province of WA's Kimberley Region is 100% owned by Gibb River Diamonds Limited (‘GIB’ or the ‘Company’). The project consists of four granted mining leases and two exploration leases within an area of 161 km2, situated 100km east of Derby. 

A diamond bearing alluvial palaeochannel named Terrace 5 extends over some 40km of the GIB project area, with channel widths of 200m to 500m. The largest diamond recovered to date from Terrace 5 weighed 8.43 carats (from Pit 82, Figure 1), with stones larger than two carats common. 

The key to exploring the Terrace 5 diamondiferous channel is to find the best alluvial trap sites which are most likely to host the highest diamond grades, these trap sites usually occur around the sediment/bedrock contact. Gibb River Diamonds Limited has completed a ground geophysics survey using the latest in Ground Penetrating Radar (GPR) technology and the Company believes we now have a fast and inexpensive breakthrough technique which can discover these trap sites and their highly prospective diamondiferous gravels. 

GIB has merged historic drilling, trenching, bulk sampling, trial mining, indicator mineral sampling and geophysical data with the latest state of the art GPR data to generate high-grade alluvial diamond trap site targets on the proven diamondiferous channels. 

These targets will be tested this year via bulk sampling and trial mining, a field program will commence in March 2018: see field video.

1.1       Diamond Valuation 

During the quarter, an independent appraisal on the data from a 1,497.57 carat parcel of diamonds previously mined from Terrace 5 was conducted. This gave a price of US$389 per carat (A$505 per carat). This is a 63% increase on the previous valuation of US$238 per carat made in April 2006. 

This substantial price increase is mainly due to the greatly increased pricing of the fancy yellow component of the parcel which has gone up by 131% to US$3,391 per carat (A$4,403 per carat). The previous valuation of the Fancy Yellows in 2006 was US$1,466 per carat. The Fancy Yellow component now constitutes 62% of the value of the whole parcel (up from 50% in 2006). 

The largest stone in the valuation parcel was a Fancy Yellow stone weighing 8.43cts. This diamond has an estimated value of US$44,482 (A$57,769) which is the equivalent of US$5,277 per carat (A$6,853 per carat). 

1.2       Valuation Composition by Quality 

The valuation parcel had a Gem content of 38%, Near-gem of 55% and Industrial of 7%. The combined Gem and Near-gem content of 93% could be considered high by world standards.  

1.3       Blina Project Diamond Valuation Summary 

The Board is very pleased with this new major increase in the valuation of the Terrace 5 diamonds. We believe it is an extremely significant development for the Company which will also have a positive effect on the economics of the Blina Diamond project. ASX Release  

1.4       Terrace 5 JORC (2012) Exploration Target 

The JORC (2012) Exploration Target for the Terrace 5 alluvials is from 700,000 to 1,000,000 cubic metres at a grade of 2.3 to 4.1 carats per cubic metre, for contained diamonds of 1.6 to 4.1 million carats.

Table 1          Exploration Target Summary

Volume  Gravels


Total  Diamonds


(carats per cubic metre)

(million carats)













Figure 2: Section View of Eroded Lamproite from E9

This Exploration Target is based on estimating the amount of ‘Missing Diamonds’ which have been eroded from the E9 pipe (Figure 2) and have ended up in the Terrace 5 palaeo channel (Figure 1). A full technical summary is detailed in the recent GIB ASX Release

This maiden JORC Exploration Target demonstrates the potential of Terrace 5 to deliver very high grades on what would be a relatively simple, shallow, low capital cost and low operating cost alluvial mining process. 

Previous explorers lacked a method of indirectly mapping the prospective bedrock-cover contact. The highly successful recent GIB geophysical survey using Ground Penetrating Radar may well prove to be a gamechanger for this project by quickly and inexpensively defining the highest quality diamond targets at this contact. The potential for discovering bonanza grades within these newly defined trap site targets presents an exciting and significant upside. 

1.5       Nine ‘High Grade’ Diamond Targets Identified 

By combining GPR and historic pitting and trenching data, GIB has identified two new discrete channels within Terrace 5. These have been named Channel 1 and Channel 2 (Figure 3). Previous testing on Channel 1 indicates it is strongly diamondiferous, Channel 2 is untested. 

Channels 1 and 2 are deeper, and presumably older, than the other defined Terrace 5 gravels in the area. The historic bulk sampling which took place over the newly defined Channel 1 gave some of the best results within the Terrace 5 system, with grades up 10.5 carats per hundred cubic metres (cphm3), see Table 2. 

Table 2: Bulk Sample Results from Channel 1


Volume (m3)

Diamond grade (carats per hundred m3)

Average diamond size (carats)

Largest Stone (carats)






















Within Channels 1 and 2, GIB has identified nine new ‘High Grade’ targets, which the Company believes are the most prospective areas within the entire Terrace 5 system. These nine ‘High Grade’ targets have minimal overburden (2 to 8 metres), lie within proven diamondiferous channels and show up on the GPR as excellent potential alluvial trap sites.

Figure 3:       High Grade Targets 1-9

Figure 4: High-Grade Targets 2 & 3 Ground Penetrating Radar with Interpretation

1.5.1 High-Grade Alluvial Diamond Trap Sites: Examples 

The bonanza grades and returns that can be found within high-grade alluvial diamond trap sites make these systems a highly desirable target for alluvial diamond miners. An example of the type of high-grade pothole trap sites GIB is looking for at Blina is shown in the photo below taken at the Auchas Diamond Mine on the Orange River in Namibia. 

Figure 5: Auchas Diamond Mine, Namibia. Potholes

1.6       Grant of Mining Leases De-Risks Project 

All four of the company’s mining lease applications were granted. This is a major step forward for the Company and reflects the considerable work and preparation which has gone into the Blina Diamond Project to date. 

The grant of these leases was assisted by securing two historic Mining Agreements with the following groups: 

  • The Bunuba Dawangarri Aboriginal Corporation (‘Bunuba’), the Traditional Owners for the southern part of the Blina Diamond Project area. ASX Release
  • The Warrwa Combined Native Title Group (‘Warrwa’), the Traditional Owners for the northern part of the Blina Diamond Project area. ASX Release 

As a result of the grant of these mining leases, the project has been significantly de-risked. The company now has the ability to immediately transition to a full-scale mining operation, should commercial diamond grades be encountered during the upcoming field seasons sampling operations. 

1.7       Lookahead Work Program 

The Company is currently involved in planning and permitting activities with the aim of conducting bulk sampling and trial mining operations at Blina in 2018. For operational reasons, it is planned to only conduct earth moving and treatment during the dry season (April to December). 

The on-site work program will commence in March 2018. Below are some of the action items which are either completed, underway or planned: 

  • Grant of Mining Leases. Completed.
  • Aboriginal Heritage and Mining Agreements in place. Completed.
  • Independent Valuation for Terrace 5 diamonds. Completed.
  • JORC Exploration Target for the Terrace 5 gravels. Completed.
  • Analysis of GPR and historical data to generate detailed alluvial targets for bulk sampling operations. Completed (further studies continue).
  • Fauna and flora survey. Completed.
  • Conduct a heritage clearance survey with Traditional Owners, a detailed notice of this survey has been given to the BDAC group. Planned March 2018.
  • Full operational permitting for bulk sampling and trial mining operations in 2018 includes an on-site alluvial treatment plant. Application lodged on 19 December 2017, follow-up is ongoing.
  • Set up an on-site camp. March/April 2018.
  • Finalise equipment contracts. March/April 2018
  • Commence systematic bulk sampling operations of priority targets. April/May 2018.
  • Set up and commission alluvial treatment plant. April/May/June 2018.
  • Recover diamonds and grade information. May/June 2018.
  • Conduct diamond sales should commercial production be achieved.