Will
you always find kimberlite if you have indicators? No. The odds are against it.
Will the kimberlite be diamondiferous? Will diamondiferous kimberlite be rich
enough to be brought to a mine? The odds decrease with each step along the way.
Read below about the efforts of some explorers to find kimberlite in Canada's
northwest Territories.
Fire
into Ice
by Vernon Mark Frolick
6 x 9 · 25 b&w photographs
1-55192-232-0
· (Cdn) $19.95 Now available in paperback
The
crews huddled inside the shack built around the drill rig. Inside, it was dark,
deafening and filthy with lubricating oil and rock dust, but Chuck noticed none
of that. He was watching the core. The rig was set up on shore and the drill angled
at 45 degrees to bore down towards the centre of the lake. They could have set
up on the ice, drilling straight down, but that presented the risk that the drill
might cut down alongside the pipe and miss it. The odds of intersecting the pipe
were better if the drill angled across the face.
After cutting through 30 metres
of rock, the tension began to climb quickly. Chuck, Hugo and Ed Schiller were
all inside, mentally counting the distance the drill had gone as the core slowly
came up. Hugo's calculations put them under the lake and into the anomalous zone,
but the rock core didn't change at all. It was all bedrock. Once under the lake,
they should have hit the pipe. But there was nothing there.
At 60 metres they
still hadn't hit kimberlite. Hugo and Chuck looked at each other but said nothing.
They were barely breathing. The drill continued, mechanically, to eat into the
Earth, beneath the lake, the noise in the shack drowning out everything but their
feelings. Deeper. Ninety metres--well under the lake--and still nothing. The anxiety
the men were feeling was intense. The tension was soaring. Everything hinged on
proving a pipe, this pipe--their best target! The years, the effort, the hopes,
the commitment, the technology, their lives, the past, present and future, all
of it was now determined by this core, which continued to rise to the surface
with no change at all in its composition. Grey, cratonic host rock. Deeper and
deeper they went.
The drill bit, now 120 metres away, continued grinding slowly
through the rock. It was impossible they could have missed the pipe--if it was
there. The feelings the men had were complex and deep. At a depth of just over
120 metres, the drill bit suddenly chewed into something different, a softer rock.
In the shack, the noise the spinning rods made changed. The pitch began to sing
To
Chuck, the sight of what followed, of the core from the narrow-bore drill being
lifted to the surface in thin, broken, stone rods,sent him into a state of near-bliss.
The drillers didn't know what it was; they had never seen rock core like it. They
had just intersected kimberlite--potentially diamond-bearing ore."
Just
how many diamonds are needed to make aa pipe economical? Some South African mines
operate at 25 carats of diamond per 100 cubic meters of rock or about 2 grams
of diamonds per 100 tons of rock. Because diamond has a specific gravity of 3.5
grams per cubic centimeter, 1 cubic centimeter of diamond weighs 16 carats. Picture
a giant 100-ton ore truck full of kimberlite - that truck contains only half of
a cubic centimeter of diamonds! Only about 35% of those diamonds are gem quality.
The Story of Indicator Minerals
- Are There Always Diamonds?
"Chuck
Fipke stood with Hugo Dummett at the edge of the ancient crater at Point Lake.
Chuck was reluctant to leave. The days and seasons were simply too short to accomplish
everything he had to do. His inclination was that they should stay and work through
the darkness of winter.
Both men wanted to drill Point Lake. It was their
best target. They knew better than the rest that Point Lake should be a pipe.
It was Hugo's call. Although the year's budget was exhausted, Hugo took a last
look around, and then said firmly, "Drill it!"
________
