Home / Adventures / 2004 / El Oso Mine Loop

El Oso Mine Trek 2004
Date 6/19/2004
Trail Time 4-6 hours
Location Four Peak, south of Hwy87 from FR143
Mapping / GPS / Waypoint File

.gif Map Image (main) / Topo 100k , 7.5' (Difficult loop) / .MPS File / .TXT File

Trail Rating: 2.5 (1-5 scale)


A high clearance SUV is required with low range gearing, very narrow in spots

Major Obstacle There is a 1/2 mile climb at the end of the loop that will challenge vehicles with open differentials, with one short ledge being the most difficult
Brush (minor, moderate, severe) Severe
Scenic Value (1-5 scale) 3: The area around the El Oso mine is very nice

Scott Brady- 1998 Isuzu Trooper
Eric- Gen 1 Isuzu Trooper
Shan- 2001 Isuzu Vehicross
Nathan-2000 Mitsubishi Montero Sport LS

The Four Peaks area and the El Oso Mine trail is a great place to explore within a short drive from Phoenix. I wanted to lead a trail for the 4x4wire Arizona Isuzu and Mitsubishi group, and felt that this trail would make the perfect introduction. We met at the start of the El Oso (four peaks) road, with everyone showing up at about 9:30. We made introductions and started to air down in preparation for the 18 mile drive on the graded road (designated FR143). This area is popular for all OHV users, so quads and trail bikes are to be expected, especially close to the highway.

We made good time as we climbed in elevation in the Mazatzal Mountains on FR143. This road eventually ends at Punkin Center NW of Theodore Roosevelt Lake. The trail rises to over 5,000' and reaches a saddle at Pine Mountain. This is where FR422 heads north leaving FR143. This road is still tame and has a few steep climbs, but traction is good. At FR463 (N33 44.741 W111 22.175 NAD83) we left the main the El Oso mine trail (FR422) and start on the Joline Mine trail. This is where all of the challenges are encountered.

Within a few hundred yards of FR463, the trail yields some challenges, including some nice slabs that will test the suspension travel of the vehicle. This portion of the trail runs along a ridge overlooking Big Pine Flat, with some nice views. This area was damaged by fire many years ago, and is now just recovering. The brush here is very tight, and is the worst you will find throughout the loop.

As the trail descends into the canyon, the rocks become larger and proper wheel placement and clearance is more of a factor. The first major rock section requires dropping down a hill over a rock outcropping and making a tight right hand turn into a series of loose boulder areas, the last being cambered and narrow. This section would be much more challenging if it had to be climbed.
The trail continues to descend towards Bull Basin, winding through dense trees and several dry creek beds. The El Oso mine horizontal shaft is located on the west side of the trail within several feet of the track. This is a very well preserved mine, with ore cart tracks still nailed to 100 year old timbers.
The mine should be entered with caution and at your own risk, but the impressive support timber structures, multiple shafts and rich quarts veins are worth the look. After checking out the mine we continued towards the Joline mine spur. There are a few more crossed axle challenges along the way with close brush, and some cambered sections. At ~2.4 miles, the trail turns west or straight. The trail straight ahead (NE) leads to the Joline Mine (horizontal shaft). There is not much parking at the mine, which is also the end of this section of trail, so turning around is somewhat difficult. There are a few trees around, so we decided to have lunch there. After turning around we worked our way the 150 yards back to the main trail and the turn west. The trail immediately begins to climb, with several loose, crossed axle and cambered obstacles. The open diff vehicles really struggled here requiring several attempts.
1998 Gen II Trooper Climb
Gen 1 Climb
VX at the start of the hill
After the loose start of the climb the hill gets even steeper, with several gully's to straddle and more crossed axle holes. About 2/3 of the way to the top the major challenge of the climb is encountered in a 2 foot ledge with several 8-12" rocks embedded in the surface. The Montero with it's open diffs and stiffer suspension struggled the most, but made the obstacle without a strap. Nathan did a great job of listening to his spotter. Eric climbed the ledge with very little wheel spin, taking advantage of his 33" tires and flexible suspension. Eric's many hours on the trail were a great advantage to him, as he did a great job driving and spotting. The Vehicross was the last to attempt the ledge and cleared the obstacle after some minor line changes.

After the ledge, the trail becomes much easier and soon rejoins FR422 (N33 46.417 W111 23.211). We had a great day, with perfect weather and a few challenges to keep things interesting. All of the vehicles and drivers performed great, with none requiring recovery or repair.
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