  We present 3-D hydrodynamical models of the evolution of superbubbles powered
by stellar winds and supernovae from young coeval massive star clusters within
low metallicity ($Z = 0.02$Z$_{\odot}$), clumpy molecular clouds. We explore
the initial stages of the superbubble evolution, including the occurrence of
pair-instability and core-collapse supernovae. Our aim is to study the
occurrence of dust grain growth within orbiting dusty clumps, and in the
superbubble's swept-up supershell. We also aim to address the survival of dust
grains produced by sequential supernovae. The model accounts for the star
cluster gravitational potential and self-gravity of the parent cloud. It also
considers radiative cooling (including that induced by dust) and a
state-of-the-art population synthesis model for the coeval cluster. As shown
before, a superbubble embedded into a clumpy medium becomes highly distorted,
expanding mostly due to the hot gas streaming through low density channels. Our
results indicate that in the case of massive ($\sim10^7$M$_{\odot}$) molecular
clouds, hosting a super star cluster ($\sim5.6\times10^5$M$_{\odot}$), grain
growth increments the dust mass at a rate $\sim4.8\times10^{-5}$M$_{\odot}$
yr$^{-1}$ during the first $2.5$Myr of the superbubble's evolution, while the
net contribution of pair-instability and core-collapse supernovae to the
superbubble's dust budget is $\sim1200$M$_{\odot}
(M_{SC}/5.6\times10^{5}$M$_{\odot})$, where $M_{SC}$ is the stellar mass of the
starburst. Therefore, dust grain growth and dust injection by supernovae lead
to create, without invoking a top-heavy initial mass function, massive amounts
of dust within low-metallicity star-forming molecular clouds, in accordance
with the large dust mass present in galaxies soon after the onset of cosmic
reionization.
