Only a couple of shipkiller mines? To cover a entire (very large) planet?

Sounds like a one-use system, to me. Also one that's rather more complex and interdependent.

My idea for such a minefield was that it's components be relatively simple, thus making them cheap to build and maintainable at even comparatively low tech levels. I also wanted them to be effectively independent of each other, so that taking out part of any field leaves the rest of it fully functional. This makes it impossible for an enemy to ever be certain that a field has been cleared, so their forces must still exercise caution, thus slowing the tempo of operations. This effect gives the concept tactical value even when - unknown to the enemy - a given field has been effectively neutralized. So while my individual mines can share data (via conventional tightbeam) when this is beneficial and prudent, that isn't required and all units can function in standalone mode.

FYI: 90% my denial minefield mines are only a small step above your "small observation sats." Roughly the size of basketballs, their armament consists of a single Stinger-scale missile. These tiny mines are intended for use against the refueling shuttles of enemy capital ships. A hit from such a mine probably won't destroy even such a minor vessel. But it would likely be enough to mission-kill that vessel. After enough fuel shuttles are lost or crippled, an enemy force must either turn back or else commit major units to skimming . . . and thus face the capital-shipkiller mines* which form the final 10% of the field.

*Capital-Shipkiller Mine = A heavily-stealthed rack of MUCH larger missiles (e.g. an instant salvo) programmed to engage higher-value targets. This mine uses a combination of internal gyroscopes and cold gas thrusters to keep its narrowest cross-section orientated toward any close active sensor source. These same low-signature thrusters are also used to alter it's orbital vector toward interception of an incoming target, when said target meets certain parameters relating to value as well as probability of successful intercept. The mine only precesses to optimal launch orientation at the last possible instant prior to missile ignition.