TSX Venture: TDC

VANCOUVER, April 3 /CNW/ - Tyhee Development Corp. (TSX Venture, TDC) (the "Company") today announced a revision to the August 2007 NI 43-101 estimate of the Nicholas Lake gold resource. The new resource reflects a change in approach to allow for bulk mining techniques, as well as the complete assaying of the archival drill core. The Measured and Indicated gold resource has increased by 27% to 311,000 ounces, and the Inferred gold resource has increased by 22% to 120,000 ounces of gold. The Ormsby and Bruce Zones have not been revised in this report.

	    ------------------------------------------------------------------------- 	    Category          Ormsby          Nicholas          Bruce          Total 	                        Zone         Main Zone           Zone       Resource 	    ------------------------------------------------------------------------- 	    Measured 	    ------------------------------------------------------------------------- 	      tonnes       2,617,000         1,249,000                     3,866,000 	    ------------------------------------------------------------------------- 	    gold grade 	     (gpt)              3.38              3.81                          3.52 	    ------------------------------------------------------------------------- 	      ounces of 	       gold          284,000           153,000                       437,000 	    -------------------------------------------------------------------------  	    ------------------------------------------------------------------------- 	    Indicated 	    ------------------------------------------------------------------------- 	      tonnes       5,620,000         1,484,000        252,000      7,356,000 	    ------------------------------------------------------------------------- 	    gold grade 	     (gpt)              3.61              3.32           2.67           3.52 	    ------------------------------------------------------------------------- 	      ounces of 	       gold          652,000           158,000         22,000        832,000 	    -------------------------------------------------------------------------  	    ------------------------------------------------------------------------- 	    M&I 	    ------------------------------------------------------------------------- 	      tonnes       8,237,000         2,733,000        252,000     11,222,000 	    ------------------------------------------------------------------------- 	    gold grade 	     (gpt)              3.54              3.54           2.67           3.52 	    ------------------------------------------------------------------------- 	      ounces of 	       gold          936,000           311,000         22,000      1,269,000 	    -------------------------------------------------------------------------  	    ------------------------------------------------------------------------- 	    Inferred 	    ------------------------------------------------------------------------- 	      tonnes       2,004,000           955,000        661,000      3,620,000 	    ------------------------------------------------------------------------- 	    gold grade 	     (gpt)              3.02              3.92           2.79           3.21 	    ------------------------------------------------------------------------- 	      ounces of 	       gold          195,000           120,000         59,000        374,000 	    ------------------------------------------------------------------------- 	    Ormsby and Bruce at 1.25 gpt cut-off  	    Nicholas Lake at 1.1 gpt cut-off 	    Figures are rounded for presentation 	    

Dr. Dave Webb, Tyhee's President and CEO said, "the increase in the gold resource of 66,000 Measured and Indicated ounces, and 21,000 Inferred ounces of gold is significant and will contribute to the overall project economics. We anticipate initiating a revision of the Ormsby Zone resource later this month, incorporating the nearly 25,000 m of new drilling completed throughout 2007. Today's announcement is the first part in our revision of the resource for 2008 as none of the drillholes completed in 2007 have made their way into the Ormsby/Bruce Lake resource."

The Nicholas Lake Main Zone resource was calculated using inverse squared estimations of 1.5 x 5 x 5 m blocks located in two domains. A search ellipsoid of 50 x 34 x 5 m at elevations above 100 m and 60 x 40 x 5 m below this elevation was employed. This new search ellipsoid is 22% to 76% smaller than the ones previously used and is believed to provide better control by limiting extrapolations.

The average tungsten content of the deposit (0.022% WO(3)) represents approximately one tenth of the gold value and is material. Initial metallurgical testing reveals gravity recoveries in excess of 70% of the scheelite (tungsten mineral). Further work on the tungsten recovery is required to properly assess its potential to contribute to the overall project economics.

Work on the Preliminary Assessment is continuing. The new Nicholas Lake resource is being incorporated into the study which is planned to be completed by the end of June 2008.

Nicholas Lake Main Zone Geology

A 300m by 200m leucocratic felsic intrusive of quartz diorite to granodiorite composition is the host for the Nicholas Lake gold deposit. Auriferous quartz-sulphide veins occur in a shear zone within, and on the southern margin of the intrusion. Gold is closely associated with fractures and open space fillings in sulphides or alone within quartz. Scheelite occurs throughout the granodiorite in concentrations of up to 20,000 ppm tungsten. Underground development allowed access at approximately 90 metres below surface. This work confirmed the continuity of the mineralization and returned assays that are comparable to nearby diamond drill holes.

Additional Drilling

Diamond drilling has continued on our Yellowknife-area properties using four drills which had been reallocated to advance targets that were only winter accessible (swamp or lake-based targets). For much of March, this meant one drill on BigSky, two drills on Clan Lake, and one drill on the Ormsby Zone. The larger 71 series BBS-25A has recently been released back to our contractor from Clan Lake while the winter road was available for demobilization. Drilling is continuing with the three remaining BBS-25A's which are limited to a maximum 500 m depth.

Tyhee has completed a total of 15 holes at Clan Lake this year, totaling over 2,700 metres. Assays are pending. As of March 24, 34 drillholes have been completed on BigSky totaling nearly 6,450 metres in 2008. These are at various stages of logging, sampling, assaying or compilation.

About Tyhee Development Corp.

Tyhee Development Corp. is a gold exploration and development company currently focused on the historic Yellowknife Gold Camp, NWT, Canada. It is the largest property holder in the belt, and has the largest exploration and development program underway in the region. Its principal asset is the advanced-stage Yellowknife Gold Project, which consists of 6,625 hectares (15,481 acres) of mining leases located 90 km (56 miles) north of Yellowknife, NWT, Canada. Additional gold properties have been acquired within the Yellowknife Gold Belt and exploration of these targets has commenced with the initial results confirming significant gold values over multiple metres on two of the three grassroots properties reported. An aggressive drill program is currently underway on all three grassroots properties and assays will be released as they are received and compiled.

Tyhee completed fire assays on drill core samples using 30 gram aliquots with ICP-ES finish for gold analyses, prepared at Acme Analytical Laboratories Ltd. in Yellowknife, and finished at Acme Analytical Laboratories Ltd in Vancouver. A semi-quantitative multi-element analysis is run on 0.5 gm aliquot samples leached in a hot aqua regia solution and measured using ICP-ES techniques. All elevated tungsten values are then reanalysed on 0.5 gm aliquots digested using phosphoric acid and measured using ICP ES techniques. Tyhee conducts a rigorous QA/QC program of inserting blanks and duplicates in the field and standards in the laboratory. The laboratory also conducted their own independent QA/QC program including inserting their own standards and rerunning samples from pulped material and reject material. These results were provided to Tyhee. All standards, duplicates, blanks and check assays returned acceptable results. Mr. V. Pratico, P.Geol., the designated QP within the meaning of NI 43-101, has reviewed this release and approves of its content.

	    NO REGULATORY AUTHORITY HAS APPROVED OR DISAPPROVED THE CONTENT OF THIS 	    RELEASE. THE TSX VENTURE EXCHANGE DOES NOT ACCEPT RESPONSIBILITY FOR THE 	    ADEQUACY OR ACCURACY OF THIS RELEASE.  	    Tyhee's shares trade on the TSX Venture Exchange under the symbol "TDC". 	    For additional information, please visit the Company's website, 	    www.tyhee.com.