3924 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
fractures radiating out from a remnant central inclusion pit
(Figure 4o) which may have provided internal weak points
for further fracture propagation and breakage. This dodeca-
hedron exhibits a complicated history of diamond growth
and resorption events (Figure 4p) as well as rare striation
marks or ‘deformation micro-twins’ running the length
of the cleaved surface. These striations result from plastic
deformation at relatively low temperatures 900–1300 °C
or impact stresses (shock loading) associated with the late
stages of diamond transportation to the surface (e.g., Titkov
et al., 2012).
Diamond Fracture Patterns Associated with
Ore Processing
Breakage patterns associated with comminution can be
broadly classified into three categories as illustrated in
Figure 4. Diamond breakage associated with geological processes. Photographs are in colour and grey-scale figures are
secondary electron (SE), back-scattered electron (SEM), or X-ray computed tomography (CT) images. (a) typical ‘chipping’
of octahedra diamonds. (b) uneven fractured surface. (c) cleaved surface. (d) serrated lamellae and typical negative trigons
produced by secondary resorption in the mantle. (e) rare triangular serrations on the octahedral vertex. (f) breakage associated
with an internal sulphide inclusion, trigons and ‘tram-line’ abrasion pits are present on the {111} face. (g) uneven breakage
surface surrounding inclusion remnants juxtaposed with the smooth, highly resorbed outer surface of the diamond. (h) SE
image depicting the flat-bottomed and truncated negative trigon pits on the surface of the octahedron. (i) BSE image showing
the compositional contrast between the inclusion and diamond. (j) an illustration of macel twin formation adapted from
Pavlushin and Konogorova (2023). (k) conchoidal fracturing at the corners, takes advantage of the twin re-entry angle planes.
(l) step features in the fracture zone run along the {111} cleavage plane. (m) brown dodecahedral diamond (photograph), with
cleavage along the inherent {111} plane (SE image). (n) dodecahedral fragment depicting cleavage along the {111} octahedral
and {110} dodecahedral planes. (o) micro-CT image of the same dodecahedral fragment (Figure 4n) in showing a remnant
inclusion pit with associated internal radial fracturing. (p) under SE microscopy, various growth zonation and resorption
features can be seen in addition to rare striation marks which crosscut the cleaved surface
fractures radiating out from a remnant central inclusion pit
(Figure 4o) which may have provided internal weak points
for further fracture propagation and breakage. This dodeca-
hedron exhibits a complicated history of diamond growth
and resorption events (Figure 4p) as well as rare striation
marks or ‘deformation micro-twins’ running the length
of the cleaved surface. These striations result from plastic
deformation at relatively low temperatures 900–1300 °C
or impact stresses (shock loading) associated with the late
stages of diamond transportation to the surface (e.g., Titkov
et al., 2012).
Diamond Fracture Patterns Associated with
Ore Processing
Breakage patterns associated with comminution can be
broadly classified into three categories as illustrated in
Figure 4. Diamond breakage associated with geological processes. Photographs are in colour and grey-scale figures are
secondary electron (SE), back-scattered electron (SEM), or X-ray computed tomography (CT) images. (a) typical ‘chipping’
of octahedra diamonds. (b) uneven fractured surface. (c) cleaved surface. (d) serrated lamellae and typical negative trigons
produced by secondary resorption in the mantle. (e) rare triangular serrations on the octahedral vertex. (f) breakage associated
with an internal sulphide inclusion, trigons and ‘tram-line’ abrasion pits are present on the {111} face. (g) uneven breakage
surface surrounding inclusion remnants juxtaposed with the smooth, highly resorbed outer surface of the diamond. (h) SE
image depicting the flat-bottomed and truncated negative trigon pits on the surface of the octahedron. (i) BSE image showing
the compositional contrast between the inclusion and diamond. (j) an illustration of macel twin formation adapted from
Pavlushin and Konogorova (2023). (k) conchoidal fracturing at the corners, takes advantage of the twin re-entry angle planes.
(l) step features in the fracture zone run along the {111} cleavage plane. (m) brown dodecahedral diamond (photograph), with
cleavage along the inherent {111} plane (SE image). (n) dodecahedral fragment depicting cleavage along the {111} octahedral
and {110} dodecahedral planes. (o) micro-CT image of the same dodecahedral fragment (Figure 4n) in showing a remnant
inclusion pit with associated internal radial fracturing. (p) under SE microscopy, various growth zonation and resorption
features can be seen in addition to rare striation marks which crosscut the cleaved surface