Diamond projects have been my geological soul mate ever since I studied geology in high school. I have always been intrigued by diamonds and the whole coloured gemstone sector.
I don’t think I was fascinated with geology, I was fascinated by coloured stones and how they appear in their crystalline forms in nature. Emeralds were my favourite, followed by coloured diamonds. White diamonds are beautiful, but they are just too vanilla.
Natural Emerald crystal (Source: Wikipedia).
My Honours thesis was on the topic of diamonds. It was after doing my Honours year in Geology that I got interested in diamond geology which was very different from the other commodities. Although I should have done better with the thesis, I did learn a lot from the research with the help from my supervisors, Dr Rob Ramsay, Dr Wayne Taylor and the late Dr Nick Rock. Without Rob and Wayne, there would not have been a thesis.
What has happened with diamond exploration?
The last time I remember a diamond exploration IPO was that by Cambridge Gulf Exploration Limited in the early 1990s. They had a plan to mine the diamonds in the Cambridge Gulf. The theory was that the action of weathering and erosional would transport diamonds from the Argyle pipe into the gulf.
There was Striker Resources which was exploring the North Kimberley Ashmore pipes in the 1990s and then went and tackled the Merlin Diamond Project. Striker changed its name to North Australian Diamond Company, and I think, later became Merlin Diamonds.
An 8.43-carat Fancy Yellow diamond (left) recovered from Blina project alluvials. This stone is valued at US$44,482 (Source: Gibb River Diamonds). An antique ring with a Blina Yellow Diamond (right).
Lucapa Diamond Co Ltd (ASX:LOM) is probably the most recent successful ASX-listed diamond Company. Lucapa is mining high-value diamonds from the Lulo (Angola) and Mothae (Lesotho) mines. They are uncovering some huge stones from their projects.
A collage of Lucapa diamonds (Source: Lucapa Diamond Company).
The Webb Project
(Source: GeoCrystal Limited IPO Prospectus)
In 2018, GeoCrystal was unsuccessful in an attempt to list on the ASX and is still an unlisted public Company. The Webb Diamond Project is approximately 500 kilometres due south of Halls Creek and 630 kilometres west of Alice Springs (Figure 1) in the remote West Arunta region of the Gibson Desert of Western Australia.
The Webb tenements contain a large cluster of bulls-eye, magnetic dipole features interpreted to be pipe-like intrusions. These geophysical targets compare to geophysical features of mantle-derived rocks found associated with swarms of kimberlite and lamproite pipes in Archean cratons and Proterozoic mobile belts that host known diamond occurrences.
Figure 1: GeoCrystal project location.
Initial modelling of the magnetic features was based on government aeromagnetic surveys flown on 400-metre line spacings. However, additional modelling took place following an aeromagnetic study carried out by Meteoric Resources in 2010 over part of E80/4235.
More detailed modelling took place following an aeromagnetic survey carried out by the company in 2014. A total of 12,574 line kilometres was flown on 100-metre line spacings, and 280 magnetic dipole features were interpreted.
Detailed modelling of selected magnetic targets indicates vertical pipe-like bodies with depths to the unweathered top of the modelled bodies ranging from 50 to 150 metres below surface and diameters varying from 180 to 300 metres.
Recent exploration by GeoCrystal
In 2013 and 2014, the company carried out the first exploration and drilling programs (7,713 metres) over these magnetic features and drilled 64 targets on tenements E80/4235, E80/4407 and E80/4506, discovering 51 kimberlite bodies. There remain 216 untested kimberlite targets at Webb.
In the period 2013 to 2015, the company undertook extensive loam (surface concentrate) sampling programs of the desert sands (totalling 42 tonnes) to determine the presence of Kimberlitic indicator minerals and microdiamonds. A total of 27 micro-diamonds were recovered with the majority within a broad surface microdiamond dispersion anomaly 150 square kilometres in area.
The surface microdiamond anomaly is characterised by a high incidence of microdiamonds and with larger dimensions up to 0.4 millimetres at its eastern margin.
During 2016 and 2017, the company applied ground penetrating Lozar radar, ground magnetic and gravity geophysical surveys on selected kimberlite magnetic targets within the Webb project area, especially over targets lying within the large surface microdiamond area. These surveys aimed to obtain a better understanding of the size, shape and depth extent of the targets and, therefore, prioritise the targets for future drilling.
A new diamond province
The Webb Project is one of the best exploration stories that I have heard. The unfortunate part is that it's a diamond story.
Looking for diamonds is as raw as you are ever going to get in the exploration industry. It is a long and slow process and, in my opinion, an intellectual tease as you have to look at geomorphology, geochemistry and damn hard work.
My experience in this industry came from my time with Ashton Mining Limited. Ashton was eventually taken over by Rio Tinto Limited (ASX:RIO). Those years were the most memorable as I got to work at the Merlin Diamond Project which later became Merlin Diamond Mine. It was great to have been involved with the discovery of the Bronzewing Gold Mine and the Merlin Mine in the first five years of my geological career.
I was the lucky one as I was supervising the drilling and not doing the stream and loam sampling, which was backbreaking work. After learning what they had to do, I was thrilled to stick to my mustard. I was like the resident at what was then called Boomerang Creek. Living in five-star accommodation and cooking five Michelin star meals as you can see below.
Boomerang Creek at Merlin Diamond Project - five-star accommodation.
Why is the Webb Diamond Project prospective?
The Webb Project may have given Australia the diamond province that has eluded great explorers since the late 1970s when Argyle was discovered. The closest project that came close to a province like Webb was the Coanjula Pipes, which was my Honours Thesis.
Ashton Mining owned the project. There was a sizeable microdiamond field that led many thoughts that the pipes were potentially a field of kimberlites or lamproites. However, analysis of the pipes showed that they were alkaline pipes and not from the mantle which produced diamonds.
GeoCrystal has been working on Webb for several years and the evidence is throwing up some very compelling evidence that one or more of the pipes are bearing diamonds. The project is now at the point where drilling will show either they are on the verge of discovering a diamond bearing field or another false hope.
Figure 2: Microdiamond field and untested magnetic targets in the Webb Project (Source: GeoCrystal Ltd IPO prospectus).
The GeoCrystal exploration is headed by Thomas Reddicliffe, who is the technical director and described the Webb project as one of the more exciting current diamond exploration projects. Mr Reddicliffe was involved in the Kimberley diamond exploration teams that discovered both the Ellendale and Argyle diamond deposits.
He also worked as the Australian exploration manager for Ashton Mining in the 1990s and continued to be prominent, working in Striker Resources and Merlin Diamond Limited - a wise 'old' man who is a probably one of the few actively working diamond geologists that has seen that much experience.
The Webb geology
As you can see in Figure 2, GeoCrystal has identified approximately 300 discrete magnetic targets. Drilling and sample analysis have confirmed the pipes show characteristics to a kimberlite. Both gravity and magnetic modelling show some of the kimberlite pipes to be potentially as large as 12-15 hectares in surface extent, at depths of circa 100 metres.
Exploration by the company has now highlighted an area to the northeast, where the most prospective untested targets need to be drilled. The discovery of larger microdiamonds has led the company to believe that this region (highlighted in pink) is the area of most significant interest.
What is interesting to me is that the hundreds of discrete magnetic targets form a series of linear NNE trending dyke–like anomalies. The relationship between these linear anomalies and the discrete magnetic anomalies has not been established.
However, you learn in exploration that nature never produces a pattern for no reason. When you have items being injected up from the mantle (a long way down), it always seeks the path of least resistance, and if there is a linear feature that allows you to come up, you do that.
What that means is that potentially, these linear features could be part of the whole endowment story for diamonds in the area.
Simplistically, what all the evidence is saying is that Webb is a Kimberlitic province that has a cluster of pipes with varying mineral geochemistry indicating that they are tapping different parts of the mantle material that are from the 'zone' of interest. Diamonds are only stable at 900–1300C and pressures between 45–60 kilobars (kB), so to identify that particular pipe from that point inside the mantle, you require statistics.
The first good news in Webb is the identification that a cluster of kimberlite, the source of the mantle (the medium in which potential diamonds are to be hosted) exists. The second is the presence of diamonds and Webb has a microdiamond trail. The third is the presence of indicator minerals which show the chemistry from that diamond formation region of the mantle.
When you have all that geochemistry sorted, you need the geomorphological factors, such as the trialling of the diamond and indicator minerals towards the northeastern region. The discovery of microdiamonds that are still showing the crystal forms means that they have not travelled that far from its source. This is an important feature. The photo of the diamond discovered by exploration activities, as shown in Figure 3, is a critical aspect.
"This small macle is one of 30 microdiamonds recovered from surface sands overlying the Webb field. Eighty per cent of these microdiamonds are concentrated in the northern part of the kimberlite field within a coherent and repeatable surface anomaly.
"Webb is a vast kimberlite field, with the pipes tested to date being sourced around the theoretical diamond-graphite transition depth. The deepest sourced pipes tested to date occur in the northern part of the field, so it is not a big stretch to imagine that the source for the microdiamonds will be found in the northern part of the field.” – Thomas Reddicliffe, GeoCrystal Limited.
Conclusion – my thoughts
I admit I love the excitement of diamond exploration. Real exploration has not been done for a long time. There have been a few companies that have gone into 'near mine' projects and then moved into production, but there has not been a discovery of sorts, especially in Australia.
The late Maureen Muggeridge led the last person or group that had any profile looking for diamonds. I may have graduated as a geologist, but I am in awe of the thing done by the likes of Maureen.
I had an insight into what is required to find diamonds and how much it cost. The most important part of diamond exploration is money and time. Both of these items are in short supply in the equity markets and especially the catch cry today is 'near-production'.
The reward for finding a producing diamond mine today is the fact you will be the one and only diamond producer in Australia. Quality stones still see a high price as companies like Lucapa will tell you. Merlin Diamonds was fetching up to $300/carat.
The Webb Project is the only project that will give you that option of spending $2-3 million and drill those targets. If you hit a diamondiferous pipe and the results are favourable, you will know immediately. There is no need to spend years looking at the trail, looking for the trail or analysing the geochemistry. This is the only diamond project that you literally can walk up to it and drill. A well-executed exploration program is also supporting the optimism.
The cluster of kimberlite pipes in a confined space with microdiamonds that are consistent with a lack of transportation is what gives me the confidence that this could be the elusive diamond province that everyone has been looking for since the discovery of Argyle and to a lesser extent, Ellendale, Merlin and Blina.
I was the supervising geologist when the Merlin Diamond Field was discovered. Although I did not realise that I had just drilled through the pipe, named Ector but really should have been named Noel, I knew I had drilled something different.
The thrill of knowing that I played a part in the discovery hole (after Excalibur which was discovered 1-2 years prior) that proved the concept of a field of pipes will be etched in my memory till I am too old to tell the story. That is what Webb can provide after all these years.