Referencing sAcH and this the schema documentation, I ended up writing the query below. It can probably be cleaned up a lot, but it functions and that's what I care about right now.
It returns the primary email of all active, non-deleted employees, effectively making an email list for your active users:
select e.email_address
from email_addr_bean_rel eb
inner join email_addresses e
on eb.email_address_id = e.id
where eb.bean_id in
(select id
from users
where deleted = 0 and employee_status = 'Active')
and e.deleted = 0 and eb.primary_address = 1
and eb.deleted = 0 and eb.bean_module = 'Users'
Important to note, is that there are two fields where a user can be active: status and employee_status. This checks the latter; just note that there are two 'status' fields, not one!