CO(2-1) and 
CO(2-1)
observations of the HL Tau/HH 30 region are presented. These observations
have high sensitivity and spatial resolution, and allow a large scale study
of the kinematics of the gas in this complex stellar group. The main
result is that HL Tau drives a powerful extended molecular outflow that has
probably blown out of its parental core on its blueward side. The red part
of the flow is currently pushing its way into the denser remaining core
gas. The mass of outflowing gas is of the order of 
and 2/3 of this mass in the red part of the
flow. The outflow rate is very high: 
, a value consistent with FU Orionis accretion rates. We
also propose that the complex molecular outflow field that we have
discovered is the result of several other molecular outflows that are
possibly associated with the optical jets in this stellar group. We deduce
from our data that the current consitution of this group consists of 
in gas and 
in stars, implying a high star formation efficiency which
approaches 
. We compute the
gravitational energy of the core and find that the HL Tau system probably
remains bound in spite of its current outflow activity. Consequences of
this for the evolution of stellar groups and clusters are discussed.
Keywords: Accretion disks - Line: profiles - circumstellar matter - Stars: pre-main sequence - ISM: jets and outflows - Radio lines: ISM